Nonverbal Imitation

Nonverbal Imitation

Typical individuals acquire many complex behaviours, such as social, recreational, and language skills, by observing and imitating the behaviours of other persons. Individuals with developmental delays, however, often fail to imitate the behaviours of others. This failure to learn through imitation constitutes a major source of developmental delays. Shaping and chaining behaviours (as discussed in Chapters 9 and 10) can help students with developmental delays acquire certain simple behaviours such as sitting in a chair, dropping blocks in a bucket, and following elementary instructions (e.g., 'Come here')- Shaping and chaining will fail, or be too impractical, however, to help the student acquire complex behaviours such as toy play, receptive language, and social skills. Teaching students with developmental delays to imitate is a major step toward helping them overcome their delays.

The ultimate goal of the Nonverbal Imitation Program is to teach the student generalized imitation. Generalized imitation takes place when the student learns to imitate novel behaviours without specifically being taught to do so. The practical advantage of imitation can be seen in one-trial learning, whereby a person merely demonstrates a new behaviour and the student immediately performs that behaviour without any assistance but the model. In an upcoming volume on advanced programs, the Observational Learning Program is presented in which the student is taught how to learn through the observation of other students learning from a teacher in a regular classroom environment. In the technical literature, such forms of newly acquired behaviours are referred to as social learning. It has been proposed that this sort of learning cannot be explained by the use of separate learning principles. However, this appears not to be the case. Research has demonstrated that such imitative behaviour can be learned and that the teacher can rely on operant learning principles (presented as discrete trials in this manual) to teach this skill. As with other matching programs, the perceived similarity in the student's and other person's behaviours may become inherently reinforcing to the student. In popular literature this is referred to as the establishment of an imitative tendency or capacity.

As for all the other programs in this manual, the skills gained through the current program are taught in a stepwise manner. The student is first taught, through prompting and reinforcement, to imitate simple behaviours of an adult, such as dropping a block in a bucket or waving a hand. Slowly and systematically, the student is taught to imitate more complex behaviours, such as playing with toys, writing, and playing preschool games. Specifically, the student is first taught to imitate certain simple gross motor behaviours, when the teacher says, 'Do this,' and concurrently demonstrates an action (e.g., dropping a block in a bucket, pushing a car back and forth, tapping a table top). Newly established imitative behaviours can be extended for learning imitation of basic self-help behaviours (e.g., drinking from a glass, brushing hair, washing hands), early and appropriate play and sports (e.g., Red Light-Green Light, Follow the Leader, shooting baskets, doing somersaults), preschool skills (e.g., drawing, writing, cutting, pasting), and appropriate social skills (e.g., crying when others cry, smiling when others smile). Through this program, the student learns to pay more attention to other people and becomes motivated to learn by watching how others behave. In short, learning to imitate the behaviours of others can do much to enhance the overall social, emotional, and intellectual development of the student.

All students can learn nonverbal imitation to some degree, but there are large individual differences in both the rate of progress and the end product. For example, all students can learn to imitate simple behaviours, such as many self-help skills, and most students with developmental delays can learn to imitate typical children playing simple preschool games, such as Ring around the Rosie. However, a small minority of students will fail to imitate even the simplest behaviours from the program as it is now devised.

Nonverbal imitation training can be started when the student has learned to sit down in a chair without engaging in too much disruptive behaviour. It may also help if the student can visually orient to the teacher. Acquisition of nonverbal imitation is further facilitated by the student's being able to follow certain basic instructions as taught in Chapters 9 and 15. Both the Nonverbal Imitation Program and the Matching and Sorting Program (Chapter 12) may be started during the first 2 to 3 full, 6- to 8-hour days of treatment.

After 1 hour into training of the present program, it should become apparent whether the student is improving or standing still (see Chapter 33). Progress is shown when the student begins to imitate one of the adult's behaviours, or at least when the prompt fading process has begun. If the student does not improve, team members need to help each other identify potential problems in their use of discrete trials, prompts, or reward delivery (see Chapter 35). Lack of progress may also mean that the kinds of tasks being taught need to be revised. For example, a limited motor skill level may not allow the student to perform the behaviours demonstrated by the teacher.

Before moving on, it is important to comment on the need for the teacher to become familiar with discrimination learning procedures (see Chapter 16). The steps involved in teaching nonverbal imitation conform to those specified in the chapter on discrimination learning.

Gross Motor Imitation Using Objects

The teaching of nonverbal imitation should be introduced by using objects (e.g., teach the student to imitate the teacher dropping blocks into a bucket, pushing a toy car, placing rings on a ring stacker, hitting a drum with a drumstick). It does not matter whether the student has already learned to use some of these objects because the Nonverbal Imitation Program teaches the student to imitate the teacher's use of these objects.

We have three reasons for recommending that the teacher use objects when beginning to teach nonverbal imitation. First, most students are reinforced by actions involving toys or come to discover the reinforcing properties after exposure to such actions. Second, behaviours that involve handling an object may be more discriminating than behaviours that involve only the body. Third, actions involving objects often create noise, providing distinct feedback that facilitates discrimination of (attention to) the association between the student's behaviour and the reinforcement provided for that behaviour (technically speaking, distinct feedback helps the student discriminate the reinforcement contingency).

When the student learns to imitate the first few of the teacher's behaviours, it may appear to the casual observer that the student has learned to imitate. However, in the majority of instances, the student has not learned to imitate, as demonstrated by the fact that many new and different behaviours performed by the teacher will probably not be imitated but rather cue already established behaviours from the student at this early stage of learning. With increased exposure to imitation training, however, the student will learn to attend to very specific nuances in the teacher's behaviours.

During the beginning stages of teaching, keep each sitting to a maximum of 5 to 6 trials, and take about 30-second play breaks between sets of trials. Sittings in the early stages of teaching should not exceed 2 minutes between breaks. As the student advances through the programs in this manual, the teacher may extend the length of sittings from 1 to 5 minutes, allowing for more trials. When it is time for a play break, signal the break with the instruction 'All done' and concurrently help the student to go and play. In all programs, signal a play break contingent only on a correct response (unprompted whenever possible). Make certain that the student does not receive a break contingent on non-compliance, a tantrum, or an incorrect response.

In the beginning of training, the student should sit next to the teacher at the table. This seating arrangement makes it easier for the teacher to manually prompt the student to imitate actions with toys. By sitting next to the student, the teacher also can better control the student's behaviour in other ways, such as preventing the student from running away. After both the student and the teacher have acquired more experience, some tasks may be easier taught by positioning the teacher and the student across from one another. Later on, the teacher and student can move away from close physical arrangements, such as sitting by a table, and instead imitation can be taught in the student's everyday environment. An advantage of starting at the table is that it allows the teacher to have better control over the teaching environment. This control helps the student attend to the behaviours the teacher models, thereby facilitating the student's rate of mastery.

The teacher needs the following materials for the first behaviour modelled to the student: two identical blocks and a large bucket made of a material that creates noise when a block is dropped into it. The second behaviour involves use a ring stacker with a flat bottom and two identical rings. Two identical toy cars are used for the third behaviour.

► Step 1

Place two identical blocks about 1 foot apart side by side in front of the bucket and on the table. Place one block in front of you, the other in front of the student. For some students it may be helpful to initially place the bucket between your knees, making it easier for the student to reach (in this scenario, you and the student should be positioned across from one another rather than side by side).

Present SD1, which consists of your saying, 'Do this,' in a loud and clear voice while concurrently retrieving the nearer block from the table and dropping it into the bucket. It may be helpful to present the SD while the student is oriented toward the teaching material. Passing the block in front of the student's eyes may also facilitate this orientation. Immediately after giving SD1, prompt Rl. Since the student already mastered Rl, dropping a block into a bucket during earlier programs, it is likely that only minimal prompting will be needed. You may prompt either by instructing the student, 'Drop block,' or by manually taking her hand, helping her to grasp the block, and moving it to the bucket. After the response is completed, reinforce the student. Repeat the trial and begin fading the prompt by gradually decreasing the amount of verbal or exposure to imitation training, however, the student will learn to attend to very specific nuances in the teacher's behaviours.

During the beginning stages of teaching, keep each sitting to a maximum of 5 to 6 trials, and take about 30-second play breaks between sets of trials. Sittings in the early stages of teaching should not exceed 2 minutes between breaks. As the student advances through the programs in this manual, the teacher may extend the length of sittings from 1 to 5 minutes, allowing for more trials. When it is time for a play break, signal the break with the instruction 'All done' and concurrently help the student to go and play. In all programs, signal a play break contingent only on a correct response (unprompted whenever possible). Make certain that the student does not receive a break contingent on non-compliance, a tantrum, or an incorrect response.

In the beginning of training, the student should sit next to the teacher at the table. This seating arrangement makes it easier for the teacher to manually prompt the student to imitate actions with toys. By sitting next to the student, the teacher also can better control the student's behaviour in other ways, such as preventing the student from running away. After both the student and the teacher have acquired more experience, some tasks may be easier taught by positioning the teacher and the student across from one another. Later on, the teacher and student can move away from close physical arrangements, such as sitting by a table, and instead imitation can be taught in the student's everyday environment. An advantage of starting at the table is that it allows the teacher to have better control over the teaching environment. This control helps the student attend to the behaviours the teacher models, thereby facilitating the student's rate of mastery.

The teacher needs the following materials for the first behaviour modelled to the student: two identical blocks and a large bucket made of a material that creates noise when a block is dropped into it. The second behaviour involves use a ring stacker with a flat bottom and two identical rings. Two identical toy cars are used for the third behaviour.

The manual prompt may be decreased by gradually providing less and less physical assistance until the manual prompt is gradually shifted to a less intrusive visual prompt (e.g., pointing to the block while presenting SD1). The verbal prompt may be faded by lowering its volume or by systematically eliminating words from the prompt, beginning with the last word. Place mastery at 9 out of 10 or 19 out of 20 unprompted correct responses.

With successive presentations of the SD, place the bucket in different positions on the table so that inadvertent position prompts (e.g., the block can only be dropped in the bucket provided the bucket is in a specific location) may be avoided. Eventually try placing the bucket on the floor, on one side of the student's chair, and then on the other side. If the student fails to respond or responds incorrectly, introduce the least amount of prompt necessary to reinstate the correct response. During prompt fading, remember to occasionally probe unprompted trials to determine whether further fading of the prompt is necessary. If the student fails to respond correctly, immediately prompt, reinforce the correct response, and then resume prompt fading. Abundantly reinforce the student if she responds without a prompt, guarding against reinforcing prompt dependency. With the bucket placed in different positions, set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses and then go on to Step 2.

► Step 2

To facilitate the discrimination between SD1 and SD2, the behaviours used as SD should be maximally different from each other. Placing a ring on a stacker is good target behaviour for SD2. Remove the bucket and blocks from the table and place the ring stacker on the table with two identical rings in front of it. Present SD2, which consists of your saying, 'Do this,' while concurrently placing a ring on the stacker. Manually prompt the correct response (concurrently with or no later than 1 second after the SD) by taking the student's hand, helping her to grasp the ring, and moving it to the stacker. Reinforce, and then repeat the presentation of SD2. Again, prompt the response and reinforce. Over the next few trials, gradually fade the prompt by, for example, decreasing the amount of manual guidance over trials until eventually a mere tap on the student's hand oral point to her ring occasions R2. After 9 out of 10 or 19 out of 20 unprompted correct responses, begin a block of trials that involves moving the ring stacker to different positions on the table.

Once SD1-R1 and SD2-R2 are acquired separately, you must help the student discriminate between the two actions by using discrimination learning procedures. Begin by placing the bucket with the two blocks in front of it and the ring stacker with the two rings in front of it on the table in front the student. Allow a 12-inch space between the two sets of objects.

► Step 3

Intermix SD1 (dropping a block in the bucket) and SD2 (placing a ring on the stacker). Because SD2 was mastered last, it is likely that the student will give R2 when SD l is presented. To avoid a no reinforced trial, prompt and reinforce R l when SD l is presented. Present mass trials of SD l while fading the prompt. Place mastery at 3 unprompted correct responses in a row. Within 2 seconds of completing mastery of SD l (dropping a block in the bucket), present SD2 (placing a ring on the stacker) and simultaneously prompt the student's correct response. In an attempt to decrease the number of prompted trials, probe with unprompted trials. Set mastery at 3 unprompted correct responses in a row. Over subsequent blocks of trials, alternate back and forth between the two instructions. If the student makes an error, as in giving R2 to SD l, do not reinforce but rather provide an informational 'No' and immediately present SD l again while prompting the response. Reinforce, and continue presenting the SD until all prompts have been faded.

With subsequent shifts between SD l and SD2, require fewer and fewer successive correct responses before presenting the alternate SD (e.g., 3 in a row, then 2, and then eventually 1). It is important to switch between SD l and SD2 after 1 unprompted correct response to each SD to help establish the discrimination. Over successive intermixed and differentially reinforced trials, the student will make fewer and fewer mistakes and eventually show that she has mastered the discrimination. This comes about because the associations between SD1-R1 and SD2-R2 are reinforced and thereby strengthened, whereas mistakes, such as SD1-R2 and SD2R l, are weakened because they are not reinforced but rather placed on extinction. Eventually the student will respond correctly without prompts the first time the instructions are presented when contrasted with one another.

The student may learn to perseverate (adopt a win-stay strategy) when several trials of a particular SD are presented in a row. Also, the student may acquire a win-shift strategy when SD l and SD 2 are systematically alternated. It is important to introduce random rotation as described in the discrimination learning chapter (Chapter 16) to counteract these and other problems. The student has mastered the discrimination once she correctly responds in 9 out of 10 or 19 out of 20 unprompted trials with the SD randomly presented.

The first discrimination is usually the most difficult and should be considered a major accomplishment by the student. As such, it is important to strengthen it. Therefore, once the student learns to discriminate between SD l and SD2, we recommend generalizing the discrimination as follows: (a) move the position of the objects to different places on the table; (b) have all team members practice giving the SD; (c) practice the discrimination across different environments; and (d) practice the discrimination off and on over the next 4 to 5 days. Be aware that a shift in environments and teachers is likely to result in the student's making errors. To maximize the student's success, change to new teachers and environments in small steps. For example, place a familiar teacher beside a new and unfamiliar teacher during the first trials, and then gradually increase the distance of the familiar teacher from the unfamiliar teacher. When changing environments, slowly move the table and chairs to other positions in the teaching room, then gradually move into other rooms of the house or to the floor.

Given that the student has mastered the SD1-SD2 discrimination, you may want to conduct generalization sessions in a little more playful and informal manner than that in which the training sessions were conducted. If the student loses the discrimination during this time, return to earlier steps and re-establish mastery before going further.

The third imitation, SD3-R3, should be maximally different from the first two imitations. Pushing a car back and forth may be used as SD3. To teach SD3, retain the original setting with you and student sitting next to each other facing the table. Place two identical cars about 12 inches apart in a horizontal line on the table. One car should be placed in front of each person.

► Step 4

Present SD3, which consists of your saying, 'Do this,' while concurrently pushing the nearest car back and forth. While performing this behaviour, manually prompt the student's response by placing her right hand on her car and helping her push the car back and forth. Reinforce the correct response. Fade the prompt by gradually lessening the amount of manual guidance. Then, instead of actually taking the student's hand and directing it toward the car, fade to a visual prompt such as pointing to the car while presenting SD3. If the prompt is faded too rapidly, the student will fail to respond correctly and you will need to go back and introduce the least amount of prompting necessary to reinstate the correct response. Remember to completely fade all prompts and to save the best reinforcers for unprompted trials. Set the criterion for mastery at 9 out of 10 or 19 out of 20 unprompted correct responses.

► Step 5

Once SD3-R3 is mastered in mass trials, teach the student to discriminate between SD3 and SD1 (dropping a block in the bucket) and then between SD3 and SD2 (placing a ring on the stacker). Remember to rehearse the earlier SD1-SD2 discrimination. If this discrimination is partially lost during the teaching of the other SD, go back and re-establish it through prompting, prompt fading, and random rotation. Once the student achieves mastery, responding correctly to the random presentations of SD1, SD2, and SD3 (for 9 out of 10 or 19 out of 20 unprompted correct responses), introduce SD4.

► Step 6

Tapping a drum may be used as SD4. Retain the original setting with the student seated next to you facing the table. Place a drum and two sticks on the table. Present SD4, which consists of your saying, 'Do this,' while concurrently picking up the nearest stick and tapping the drum. Simultaneously prompt the student's correct response by manually helping the student to pick up her stick and tap the drum. Reinforce the correct response. Fade the prompt gradually over the next several trials by decreasing the amount of manual guidance. If the student fails to respond or responds incorrectly, go back and introduce the least amount of prompting necessary to reinstate the correct response. Completely fade all prompts. Set mastery at 9 out of 10 or 19 out of 20 unprompted correct responses.

► Step 7

Once SD4 (tapping the drum) is mastered in mass trials, teach the student to discriminate between SD4 and SD l (dropping a block in the bucket), then SD4 and SD2 (placing a ring on the stacker), and finally SD4 and SD3 (pushing a car back and forth). Once these discriminations are mastered (for 9 out of 10 or 19 out of 20 unprompted correct responses), intermix all four SD at once. If the table size does not allow for simultaneous presentation of all four sets of objects, present two or three sets of objects at a time. Remember, however, to randomly rotate the presentation of all four SD.

Additional Imitations Using Objects

Once the student masters the first four imitations, try adding novel imitations by relying on the experience gained from establishing the earlier ones. The following are examples of possible choices for the next several imitations:

Additional Imitations Using Objects SD  'Do this'

pretend drinking from a cup

pretend eating toy food

throwing a crumpled napkin in a wastebasket placed next to the table

putting a doll in a crib (use two identical dolls)

putting on a hat (avoid the loose, floppy kind)

pushing a toy car down the ramp of a toy garage

galloping a toy horse across the table

turning the handle on a jack-in-the-box

tapping a xylophone (any keys) with drumsticks

shaking a tambourine

banging a toy hammer

placing two animals inside a pen (use four identical animals)

brushing hair

pretending to read a book

vacuuming the floor with a toy vacuum cleaner

The imitations are listed in order of apparent level of difficulty. Given the large individual differences that exist among students, however, what may be easily mastered by one student may be difficult for another student. If little or no progress is made on any particular imitation after 1 hour, try another action and return to the difficult imitation later.

Note that any one of the imitations listed can be used as a springboard for teaching similar imitations. For example, SD5 (drinking from a cup) may be extended to picking up a spoon and placing it in a dish, picking up a napkin and wiping one's mouth, and a host of other actions associated with eating at the table. Given the supply of reinforcers and models of appropriate behaviours readily available at mealtimes, there are abundant opportunities for extending the Nonverbal Imitation Program to this everyday setting (see Chapter 21 on self-help skills).

Just as SD5 provides for an extended range of learning opportunities, SD8 (putting a doll in a crib) may also be extended. For example, teaching the child to imitate kissing a doll, patting a doll on its back, stroking a doll's hair, feeding a doll, and placing a doll in a crib helps establish appropriate play behaviour (see the section on playing with dolls in Chapter 19). Such appropriate play behaviour may be begun by requesting, 'Do this,' while modelling the behaviour. Later this request could be transferred to the instruction 'Play with dolls' as the model is faded out (see Chapter 15).

Another example of how a single SD can be extended to develop new behaviours may be illustrated by teaching the student, through imitation, to push a car down the ramp of a toy garage (SD10). This behaviour may lead to going up the ramp with the car, driving the car onto the car elevator, turning the handle to move the car up to the top of the garage, driving the car up to the pump, and filling up the tank with gasoline (see the section on playing with cars in Chapter 19). This kind of play may later be extended to larger units of play in which the student pretends her tricycle is a fire engine, which she fills up with gas before driving off to put out an imaginary fire.

SD7 (throwing a crumpled napkin into a wastebasket) may easily be extended to teaching the student to tidy up after snacks. SD9 (putting on a hat) could be the beginning of teaching the student to dress independently. SD13 (tapping a xylophone) may be extended to imitating the use of other instruments (e.g., triangle, tambourine, tone blocks, rhythm sticks). SD17 (brushing hair) could be extended to the student's brushing teeth, washing face, and similar personal hygiene behaviours.

Note that it is virtually impossible, or at least highly impractical, to shape each of these behaviours separately; however, shaping comes in handy as an additional step for fine-tuning the student's play and self-help skills so they become closer to those of typical individuals. It should be further noted that if you target several behaviours within one area (e.g., doll play), the student is more likely to acquire generalized imitation of behaviours within the same area. Generalized imitation is less likely to occur with a radical change in the SD, such as moving from self-help to doll play.

You may notice that some imitations require two relatively complex behaviours. These may be referred to as two-part imitations. For example, mastery of imitating your feeding a doll requires that the student retrieve both the doll and the bottle and then put the bottle to the doll's mouth. Given this complexity, some students fail to imitate such behaviours. Students who experience difficulty may be taught in a two-step process: First, the student should be taught to imitate the behaviours separately. Second, the behaviours should be chained together. It is to the student's advantage for you to delay the imitation of complex behaviors until a relatively large number (50 to 100) of simpler imitations is mastered. See 'Chaining Two-Part and Three-Part Imitations' later in this chapter for specifics on how to teach complex imitations.

It may seem to some that training such as that described in this section (e.g., in the case of table manners) is unduly intrusive. However, it must be remembered that typical persons acquire many socially appropriate behaviours through similar procedures, although to a less intense degree. For example, it is not unusual to observe parents of typical children modelling appropriate eating behaviours for their children and correcting and shaping eating, dressing, and similar behaviours for years to come.

Maintenance and Generalization

Keep mastered imitations maintained on a schedule adapted to the student's particular needs. For some students, the various imitations must be worked through at least once per day. Other students maintain their skills when they are practiced once per week. As the schedule is thinned out, the student's performance demonstrates whether mastery of the imitations is maintained.

Generalize imitative skills across objects by introducing non-identical exemplars of target items. For example, imitating drinking with various kinds of cups should be introduced, as should putting different kinds of hats on one's head, pretending to read a number of different books, and so on. Not only does such a procedure facilitate generalization, it also tends to keep students motivated and less likely to become bored and noncompliant. Remember, generalization should be done across persons, environments, and target stimuli.

Gross Motor Imitation without Objects

We recommend starting with gross motor behaviours because they tend to be more discriminable than fine motor behaviours. Examples of gross motor movements include standing up, sitting down, tapping a knee, clapping one's hands, raising a foot, raising one's arms, and waving. We also recommend starting with motions related to parts of the body the student can readily observe, as well as motions that you can readily and manually prompt (e.g., motions that can be demonstrated with one hand and prompted with the other).

Tapping a knee is used as SD1 for illustrative purposes. You and the student should sit facing each other with your knees slightly touching the student's. Note that the table is not necessarily involved in this kind of imitation. Other than that, the teaching procedures for gross motor movements are virtually identical to those presented earlier for imitating actions done with toys.

► Step 1

Present SD1, which consists of saying, 'Do this,' while tapping your left knee twice with your left hand (to allow prompting using your right hand). The hand movements should be exaggerated, as in lifting your hand at least 10 inches above your knee between taps. Exaggerated movements may help the student orient to SD1. Once SD1 is presented, immediately and manually prompt the correct response by taking the student's right hand (with your right hand) and assisting him in tapping his right knee twice. Reinforce the correct response.

Fade the prompt over subsequent trials by gradually reducing the amount of manual guidance provided to the student. Fading may be initiated by merely guiding the student's hand toward his knee. In fading the prompt over the next several trials, let go of the student's hand halfway to his knee, then just pull his hand out of his lap and in the general direction of his knee. If the student fails to respond correctly on any given trial, go back and introduce the least amount of prompting necessary to reinstate the correct response. Remember to eventually fade all prompts and save the best reinforcement for unprompted trials. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses (the criterion for mastery is reduced based on mastery of earlier imitations using toys). If the student is unable to imitate without the use of prompts, use the procedures described in 'Areas of Difficulty' presented later in this chapter

In illustrating the following step, raising a foot is used as SD2. Raising a foot is different from SD1 (tapping a knee) and is therefore likely to facilitate the student's discrimination. Like SD1, raising a foot makes manual prompting and the presentation of the SD possible to do simultaneously. To make the SD and the prompt as clear as possible for the student as well as the teachers, agree as to whether the student should lift the left, the right, or both feet as the correct response (the left foot is used here as the correct response to SD2).

► Step 2

You and the student should sit on chairs facing one another, with the student's left foot on top of your right shoe. Present SD2, which consists of saying, 'Do this,' while simultaneously raising your right foot at least 20 inches off the floor. Immediately prompt the correct response by raising your right foot, thus lifting the student's foot up. By doing this, both your hands are free to reinforce the student or to be used for additional prompting, if necessary. Be sure to reinforce the student while his foot is raised high. If reinforcement is postponed until the student's foot is back on the floor, lowering his foot may be accidentally reinforced behaviour incompatible with raising his foot).

Fade the prompt gradually, by first lifting the student's foot halfway up, then by merely giving his foot a little upward push with the tip of your shoe. If the student fails to respond correctly on any given trial, go back and introduce the least amount of prompting necessary to reinstate the correct response. Remember that all prompts must be faded and the best reinforcers should be saved for unprompted trials. Once the student achieves mastery of SD2 (5 out of 5 or 9 out of 10 unprompted correct trials), go on to Step 3.

► Step 3

Begin discrimination training between SD1 and SD2. Present SD1 (tapping a knee) first. Because SD2 was mastered most recently, it is likely that the student will give R2 (raising a foot) when SD1 is presented. To avoid a non-reinforced trial, prompt and reinforce R l when SD1 is presented. Remember to probe unprompted trials so as to possibly decrease the number of prompted trials and help reduce prompt dependency. Place mastery at 2 unprompted correct responses in a row. Within 2 to 3 seconds of completing mastery of SD1 (tapping a knee), present SD2 (raising a foot) and simultaneously prompt the student's correct response. Set mastery at 2 unprompted correct responses in a row. Over the next few trials, switch back and forth between the two instructions while fading the prompt and differentially reinforcing correct responses (i.e., provide greater reinforcement for correct unprompted trials than for prompted trials, and provide an informational 'No' for incorrect responses). Switch after 2 unprompted correct responses in a row, then after 1. Finally, subject SD1 and SD2 to random rotation. Once this stage is reached, place mastery at 9 out of 10 or 19 out of 20 unprompted correct responses.

Once the discrimination between SD1 and SD2 is mastered, we recommend that this discrimination be practiced across team members and gradually introduced across different locations. This is consistent with our earlier recommendation regarding the first discrimination: The first discrimination should become firmly established so as to facilitate the student's learning of subsequent discriminations.

SD3 is illustrated as raising an arm. Raising an arm is perceptually different from SD1 (tapping a knee) and SD2 (raising a foot) and is therefore likely to facilitate discrimination. Raising an arm also allows for a manual prompt to take place simultaneously with the presentation of the SD. To help make the trial as discrete as possible, agree as to whether the student should lift the left or the right arm, or both, as the correct response to SD3. For illustration, the left arm will be used as the correct response to SD3.

► Step 4

You and the student should sit on chairs facing each other. Present SD3, which consists of saying, 'Do this,' and concurrently raising your right arm while simultaneously prompting the student's correct response. Prompting may be done by taking hold of the student's left hand with your right hand and raising the student's hand up with yours. Remember to reinforce the student while his arm is still raised high, not while he lowers it (which would reinforce a response that is incompatible with raising his arm). Fade the prompt over the next several trials by removing your manual assistance when the student's arm is halfway up, then fading the prompt to merely giving the student's arm a push upward. Finally, fade the prompt to giving the student's elbow a push upward with your right hand as you raise your arm. If on any trial the student does not respond appropriately, go back to a stronger prompt. Once SD3 is mastered (5 out of 5 correct or 9 out of 10 unprompted correct trials), go on to Step 5.

► Step 5

Before intermixing SD1 (tapping a knee), SD2 (raising a foot), and SD3 (raising an arm), rehearse the earlier SD1SD2 discrimination, which may have been partially lost while establishing SD3. Next, reintroduce SD3. Prompt if necessary and set mastery at 2 unprompted correct responses in a row. Within 2 seconds of completing mastery of SD3, present SD1 (tapping a knee). Over successive intermixed and differentially reinforced trials, the student will make fewer and fewer mistakes and eventually show he has mastered the discrimination between SD1 and SD3. After this occurs, reintroduce SD2, intermixing SD2 and SD3. Finally, intermix the three SD, one at a time, according to the random rotation paradigm. Place mastery at 9 out of 10 or 19 out of 20 unprompted correct responses.

Touching tummy may be used as SD4 because the action is different from the three earlier instructions, it may be observed by the student, and it is easy to prompt. Use the same procedures for teaching SD4 as were described for teaching SD3. Remember to intermix SD4 with the other SD after it has been mastered separately. The intermixing of the various SD rehearses and thereby maintains the accuracy of the earlier mastered imitations. When introducing new SD, the teacher may receive some guidance from the following list of behaviours.

Additional Gross Motor Imitations SD 'Do this' SD 'Do this'

Flexing upper arm muscles (showing how strong you are)

Waving bye-bye clapping hands

Holding arms out to sides

Touching feet

Patting side of bottom

Touching elbow touching ears standing on knees touching neck slapping thighs standing on one foot doing a somersault

Rocking body back and forth

Sitting Indian style throwing kisses walking on knees

Covering eyes with hands

Touching throat touching heel

Imitation of finger games and songs (e.g., Itsy-Bitsy Spider, Roly-Poly; Head, Shoulders, Knees, and Toes; Five Little Monkeys) may also be taught to help prepare the student for participation in group settings, such as preschool. Some of these games and songs appear to have intrinsically reinforcing properties for many students, suggesting that they will be maintained by little or no extrinsic reinforcement (e.g., social approval, food).

Maintenance and Generalization

By now the student may have learned more than 50 single nonverbal imitations involving objects and gross motor activities. We recommend that you organize the SD into two schedules, a Maintenance Schedule and a Current Schedule. The Current Schedule should identify the more recently mastered SD as well as the SD on acquisition. The SDs on the Current Schedule need to be practiced every day. A senior team member should be assigned the responsibility of keeping the Current Schedule up to date with weekly adjustments (e.g., the status of prompts) for each item. Another team member should be given the responsibility of updating and assigning the regular work-through of items on the Maintenance Schedule. The Maintenance Schedule should contain the SD mastered and frequently practiced in the past and should be done on a regular schedule so as to ensure these items are not forgotten. The frequency of work-through for each program on a maintenance schedule has to be adjusted for each student you work with as the amount of practice required to maintain skills varies from student to student. Note that a maintenance schedule is helpful for most or all of the programs presented in this manual.

What to Expect

The nonverbal imitation skills presented thus far are mastered by almost all students. Most students make rapid progress and seem to enjoy this program, and some students begin to spontaneously imitate adults' gross motor behaviours. For example, a boy may begin to imitate the way some males walk, with their legs apart and with large arm movements ('walking big'), whereas a girl may begin to walk more gracefully. Such imitation suggests the early beginnings of sex-role differentiation. At this time boys may be introduced to a larger proportion of imitations with boy-oriented objects (e.g., trucks, tools, and male Disney figurines such as Peter Pan, Aladdin, Quasimodo, Woody, and Buzz), whereas girls may receive a larger proportion of imitations dealing with girl-oriented objects (e.g., dolls, dollhouses, toy stoves, and female Disney figurines such as Belle, Wendy, Pocahontas, the Little Mermaid, and Esmeralda). Given the large overlap in gender roles, parents are advised to use their own judgment as to whether and to what extent the imitation programs should be differentiated.

Considering individual differences and difficulty predicting what will be easy or difficult for any one student, you are advised to be flexible in deciding which imitations to introduce. For example, raising one's arms may seem an easy imitation to master, yet many students show difficulty acquiring this behavior. Or, the response may be imitated but weakened into a partial and minimal response, making it difficult to decide whether to reinforce. It is as if students are extremely efficient at minimizing efforts while maximizing gains, a trait common to all humans. If any particular imitation creates an unusual amount of effort to teach, postpone teaching it until later.

You may encounter problems helping the student discriminate between behaviors that appear similar. For example, imitations involving adjacent body parts (e.g., touching shoulders vs. touching tummy) require more training than distinct acts (e.g., touching head vs. jumping up and down). The same problem may occur when teaching behaviors the student cannot observe herself performing (e.g., touching teeth vs. touching lips, or touching chin vs. touching throat). The imitation of subtle and minute body movements (e.g., smiling vs. frowning) should be undertaken only after the student masters 20 or larger body movements.

Tasks for Improved Finger-Hand Dexterity

Fine motor imitations, such as pointing, picking up tiny objects, holding a pencil correctly, and stringing beads, are likely to be difficult for the student to imitate because these behaviours require the student to attend to (discriminate) very subtle visual stimuli. Also, the motor movements involved may not be well developed in some students. Many students need separate training to improve their hand and finger dexterity in order to progress to learning skills in programs that require mastery of fine motor skills (e.g., pointing to objects, drawing, writing, and cutting). We strongly recommend diligent practice of the following tasks before or concurrent with the teaching of fine motor imitations. Nonverbal imitation may be used to prompt dexterity tasks (e.g., say, 'Do this,' while demonstrating the target action). The exercises are ordered in apparent degree of difficulty.

Finger-Hand Dexterity Imitations SD 'Do this'

pouring beans/rice/water from small mug into wide then narrow container

spooning rice/flour from one bowl to another and then to a cup, changing from a big spoon to a smaller spoon

putting cylindrical blocks into a shape sorter (tape the other holes shut)

pulling apart two blocks of Legos

removing the tops of big markers

putting the tops back on big markers

crumpling tissue paper

turning the dial on a toy telephone

pinching Play-Doh

opening and closing the Velcro on a shoe

unzipping a zipper (finding a reinforcer inside)

picking M&Ms/raisins/beads/pennies out of an egg carton

picking party toothpicks from a pile of Play-Doh/Styrofoam and placing them into a cup/bottle

picking up party toothpicks from the table and placing them in a pile of Play-Doh or piece of Styrofoam

picking up pennies from the table and putting them into a piggy bank

stringing beads (starting with big wooden beads and gradually moving to smaller ones)

lacing cards (starting with a few large holes and gradually moving to several small holes)

picking up small objects with kitchen tongs and dropping them into a container

squeezing/pulling the trigger of a toy gun

placing hair clips in a doll's hair

placing clothespins around a paper plate

twisting nuts onto large bolts, then smaller bolts

unscrewing a lid (finding a reinforcer inside)

tracing stencils

stringing rubber bands on a peg board

unbuttoning a pocket (finding a reinforcer inside)

Fine Motor Imitations

We suggest starting fine motor imitations with exercises that are functional for the student and ones the student is likely to succeed at performing. We have chosen making a fist as SD1 and pointing as SD2 for two reasons. First, it is relatively easy to manually prompt making a fist. Second, pointing is a functional behaviour given that the student must point in most receptive language programs when asked to identify target items.

In the following steps, the student should sit facing you so he can easily observe your actions. Note the similarity between these teaching steps and those presented earlier.

► Step 1

Present SD1, which consists of saying, 'Do this,' while raising your left hand and making a fist. Slow and exaggerated motions may help the student orient to the SD. Immediately and manually prompt the student's response by raising his right hand with your right hand while curling his fingers into a fist. Reinforce the correct response. Fade the prompt in gradual steps until you eventually only need to nudge the student's knuckles with your fingers, and then just give his elbow a little push upward, and so on. If on any trial the student does not respond appropriately, go back to a stronger prompt. Place mastery at 5 out of 5 or 9 out of 10 unprompted correct responses. After this criterion is met, go on to teach SD2.

► Step 2

Present SD2, which consists of saying, 'Do this,' while making a fist with your left hand then stretching your index finger out to a pointing position. Immediately prompt the student to respond correctly. This may be done by placing your right hand on the student's fist and teasing out his index finger with your index finger. Fade all prompts gradually over the next several trials. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses.

► Step 3

Intermix and differentially reinforce SD1 (making a fist) with an already mastered gross motor imitation. Then randomly rotate SD1 with one or two other mastered gross motor imitations. Next, intermix and differentially reinforce SD2 (pointing) with an already mastered gross motor imitation and then randomly rotate SD2 with one or two other mastered gross motor imitations. The gross motor imitations serve as contrasting stimuli and are introduced to facilitate the discrimination of (attention to) SD1 and SD2. When mastery is achieved (i.e., the student responds correctly in 9 out of 10 or 19 out of 20 unprompted trials), go on to Step 4, which involves intermixing SD1 and SD2 with one another.

► Step 4

Present SDL Prompt and reinforce the response. Fade the prompt and place mastery at 2 unprompted correct responses in a row. Within 2 to 3 seconds of completing mastery of SD1, present SD2 and simultaneously prompt the student's correct response. Set mastery of SD2 at 2 unprompted correct responses in a row. Over the next several trials, alternate back and forth between the two instructions (SD1 and SD2) while fading the prompt and differentially reinforcing correct responses. Remember to occasionally probe unprompted trials to ascertain whether the student can respond correctly without further prompting. Switch SD after 2 correct responses in a row, then 1. Over successive intermixed and differentially reinforced trials, the student will make fewer and fewer mistakes. Once the student is able to respond correctly without prompts the first time the instructions are contrasted, randomly rotate the presentations of SD1 and SD2. Place mastery at 9 out of 10 or 19 out of 20 unprompted correct responses in trials with the SD randomly rotated.

The following are examples of additional fine motor imitations, listed in apparent degree of difficulty.

Additional Fine Motor Imitations SD 'Do this'

pointing with both index fingers in the air

'walking' across table with index and middle fingers

repeatedly bending and stretching index finger(s)

pointing to nose

putting tips of index fingers together

putting tips of thumbs together

tapping the tips of the index finger and thumb on same hand together (making a 'talking beak')

folding hands

pointing to lips

folding hands then 'winging' fingers up and down like a flying bird

pointing to eyelids

placing the tip of the thumb on your nose then fanning out the other fingers (as done when teasing someone)

pointing to teeth

making a peace sign

drumming on the table with fingers

making a fist and then, one at a time, fanning out fingers starting with the thumb (as if counting from 1 to 5)

fanning out fingers on the left hand, then with right index finger pointing to one fanned-out finger at the time (as if counting the fingers)

If it is difficult for the student to differentiate pointing to or touching parts around the head that cannot be observed (e.g., pointing to nose vs. pointing to mouth, touching cheeks vs. touching chin), postpone such discriminations until additional imitations are mastered.

Maintenance

Up to this point, the student has acquired a variety of nonverbal imitations involving objects, as well as gross and fine motor imitations without using objects. Gradually transfer all mastered imitations to the Maintenance Schedule and continue to practice them according to the individual student's needs. Note also that mastered nonverbal imitations should be intermixed with difficult discriminations (e.g., fine motor discriminations), as well as the skills involved in more difficult programs (e.g., the Verbal Imitation Program, Chapter 22). This will help maintain the student's attention and motivation.

Imitation of Facial Motions and Expressions

Motions involving the mouth (e.g., blowing, smacking lips, sticking out one's tongue) and facial expressions (e.g., smiling, frowning, pretend crying) require the student to attend to (discriminate) visual stimuli that are even more subtle than those presented in the previous section. Further, because the student cannot observe her own responses when performing imitations involving the face, it may be difficult for the student to acquire the discrimination of separate motions. Consequently, we recommend postponing teaching the imitation of facial motions until after the student has acquired a number of gross and fine motor imitations, after more functional behaviours have been taught (e.g., early receptive language), and after the teacher has gained more teaching experience.

Imitation of oral-motor motions helps the student gain strength and control over mouth and tongue muscles, which in turn may facilitate prompting and acquisition of correct articulation during verbal imitation training. Imitation of facial motions and expressions helps the student become more aware of your expressions and her own facial expressions. We suggest starting with blowing (SD1), opening mouth (SD2), and sticking out tongue (SD3), motions that are relatively easy to prompt. When mastered, these imitations may facilitate the imitation of other more difficult facial motions. If any one of these first responses seems particularly difficult for the student to learn, substitute it with another response from the Additional Facial Imitations list, provided later.

Begin by sitting on the floor at face level with the student. This positioning optimizes the student's opportunity to attend to (discriminate) the visual stimuli presented to her.

► Step 1

Present SD1, which consists of saying, 'Do this,' and then blowing. Do not blow in the student's face, as she might find this aversive. If the student responds incorrectly or fails to respond within 5 seconds, provide a consequence (e.g., an informational 'No') and then repeat the SD, prompting the correct response. For example, with a neutral face and as little lip movement as possible say, 'Do this.' Then open your mouth wide, draw in air, and let out a long, audible blow. Such an exaggerated demonstration may help the student attend to the SD. Gradually fade the visual prompt over the next several trials. If the student fails to respond with this prompting procedure, try the prompt suggested later in the 'Areas of Difficulty' section. Shape stronger blowing by using differential reinforcement. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses.

► Step 2

Present SD2, which consists of saying, 'Do this,' and then opening your mouth. If the student does not imitate the behaviour within 5 seconds, repeat SD2 and prompt the correct response. For example, with a neutral face and as little lip movement as possible, say, 'Do this,' and then suddenly open your mouth wide. Keep your mouth open for 3 to 5 seconds. Opening one's mouth is a subtle as well as soundless behaviour, and if the student does not pay close attention to your face, she may not notice the action or discriminate the difference between a closed and an open mouth. If necessary, try to prompt the student's mouth open with your fingers. If the student resists a manual prompt, try the prompting procedure suggested later in the 'Areas of Difficulty' section. When the student masters SD2 (responding correctly in 5 out of 5 or 9 out of 10 unprompted trials), go on to Step 3.

► Step 3

Intermix and differentially reinforce SD l (blowing) with a contrasting stimulus, such as an already mastered gross motor imitation (e.g., touching tummy). Once that discrimination is mastered, intermix and differentially reinforce SD2 (opening mouth) with a contrasting stimulus, such as a gross motor imitation that is mastered but different from the one intermixed with SD l (e.g., clapping). The gross motor imitations serve as contrasting stimuli and are introduced to facilitate the discrimination among SD l (blowing) and SD2 (opening mouth), which are difficult to tell apart given that both instructions involve facial motions. Once both discriminations are mastered, go on to Step 4, intermixing SD l and SD2.

► Step 4

Present SD l (blowing after saying, 'Do this'). Prompt and reinforce the correct response.

Fade the prompt over subsequent trials. Place mastery at 2 unprompted correct responses in a row. Within 2 to 3 seconds of completing mastery of SD l, present SD2 (opening your mouth after saying, 'Do this') while simultaneously prompting the student's correct response. By quickly prompting, you help prevent the student from making an error. Set mastery of SD2 at 2 unprompted correct responses in a row. Over the next several trials, alternate in blocks of trials between the two instructions (SD l and SD2) while fading the prompt and differentially reinforcing correct responses. Switch SD after 2 correct responses in a row, then after 1. Over successive intermixed and differentially reinforced trials, the student will make fewer and fewer mistakes and eventually respond correctly without prompts the first time the instructions are contrasted with one another. As always, if the student fails to respond or responds incorrectly, reinstate the least intrusive prompt that establishes correct responding. The student has mastered the discrimination when she responds correctly in 9 out of 10 or 19 out of 20 unprompted and randomly presented trials.

► Step 5

Present SD3, which consists of saying, 'Do this,' and then sticking out your tongue. If the student responds incorrectly or does not respond within 5 seconds, provide a consequence and prompt the correct response on the next trial. For example, with a neutral face and as little lip movement as possible, say, 'Do this,' and then stick out your tongue as far as you can, keeping your tongue out for 3 to 5 seconds. If the student does not correctly imitate the action, try the prompting procedure described later in the 'Areas of Difficulty' section. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses. Next, intermix SD3 with a contrasting stimulus, such as a previously mastered gross motor imitation. Once this discrimination is mastered, intermix SD3 (sticking out tongue) with SD l (blowing) and SD2 (opening mouth) following the procedures described in Step 4.

After the student learns to imitate blowing, opening mouth, and sticking out tongue, teach the student to imitate following the behaviours.

If any one of these behaviours seems particularly difficult for the student and the task becomes too time-consuming, teach a different behaviour from the list. Use your own experience with the student you are teaching when developing and fading prompts for subsequent imitations.

Additional Facial Imitations SD  'Do this'

smacking lips

biting lower lip

pressing lips together (start from open mouth)

tapping teeth together (open and close several times)

placing tongue between teeth and blowing

moving tongue straight out and up and down left to right, or in and out

biting upper lip

pursing lips tight and kissing

puffing out cheeks with air and then letting air out

sucking in cheeks (making a 'fish mouth')

placing tip of tongue behind lower teeth

opening mouth, placing tip of tongue behind upper teeth, and then moving tongue up and down (as in slow, soundless la-la-la)

making 'raspberries'

sticking tongue out and curling it like a tube

drawing upper and lower lips in over teeth

biting lower lip, then blowing air

licking lips

nodding head 'yes'

shaking head 'no'

sneezing

coughing

laughing

pretending to cry

looking angry (exaggerate)

looking happy (exaggerate)

looking sad (exaggerate)

looking surprised (exaggerate)

looking scared (exaggerate)

Maintenance

At this time, we suggest merging the four groups of imitations into two lists, one list consisting of mixed imitations for the Current Schedule (i.e., recently mastered SD with one to three SD on acquisition being practiced daily) and one list consisting of mixed imitations for the Maintenance Schedule (i.e., previously mastered SD being practiced less often but regularly). The variety inherent in mixed imitations should help the student stay focused and motivated.

By now the large number of imitations transferred to the Maintenance Schedule probably requires a considerable amount of time to be reviewed. To help make it practical to maintain these SD, we suggest grouping them. For example, if the student has a maintenance schedule of 70 SD, we suggest that the SD be arranged in mixed groups of 10 and that one group be practiced every day such that all 70 SD are practiced in a week.

Areas of Difficulty

Some students need stronger prompts to learn a task than the prompts described previously. In this section, we suggest particular prompts for some gross, fine, and facial imitations that have proven to be effective when the usual prompting procedures fail.

Gross Motor Imitations

Suppose the student experiences problems with gross motor imitations even with the use of physical prompts. For example, the student may not make progress (the prompts are not able to be faded) at imitating your tapping a knee. If this occurs, an object should be added to the imitation. To illustrate a prompt for the example just given, both you and the student could use a block to tap knees. The visual cue provided by the block is likely to help focus the student's attention on the movements.

For this prompting procedure, use two identical blocks of a size comfortable for the student to grab and hold. The student should be seated facing you in such a fashion that the student's right knee is touching the inside of your left knee. Put a block in the student's hand and then, holding his hand with the block in it, pick up the other block and present the SD ('Do this') while tapping both blocks two to three times on the student's knee. Reinforce. Fade the prompt gradually by first switching the tapping of your block from the student's knee to your own knee while still manually prompting the student to tap his knee with his block. Next, slowly move your leg away from the student's leg. Then fade the manual assistance of holding and tapping the student's block on his knee until he taps the block without a physical prompt. Discard your block and tap your knee with your hand. Finally, remove the student's block. If the block cannot be removed at this stage, gradually fade in the use of a smaller block and then proceed again with the fading process. When mastery is achieved (9 out of 10 or 19 out of 20 unprompted correct responses), return to the next step in the main program section.

You may use the same block prompt procedure when teaching other imitations, such as touching head, touching tummy, touching nose, and touching ear.

Fine Motor Imitations

Some students have problems with fine motor imitations, such as imitating making a fist. To help remedy this problem, use a long pencil (or similar stick) for the student to hold. Present the SD ('Do this') while grabbing the upper end of the pencil with your left hand and holding it up in front of the student. With your right hand, take the student's right hand and curl his fingers around the lower part of the pencil so he makes a fist around the pencil. Reinforce. Fade the pencil prompt gradually over the next several trials by having the student grab the pencil himself and placing your hand further and further down so that the student's end gets shorter and shorter and less and less of his fist is made around the pencil. Or, replace the pencil with a thinner pencil or stick, then with a twist tie, and then with a thin piece of wire. If you fade the prompt too quickly, go back and introduce the least amount of prompting necessary to reinstate correct responding. Remember to occasionally probe unprompted trials to ascertain whether the student can respond without a prompt. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses, then return to the next step of the main program section.

Facial Imitations

Some students have problems with certain facial imitations. Suppose a student has a problem imitating blowing. To help prompt blowing, you may employ a toy instrument that makes a sound when blown into (e.g., harmonica, whistle, and flute). Present the student with a number of such instruments to choose from in order to maximize the probability that the student will find one she likes. Do not present the verbal part of the instruction ('Do this') if it makes demonstration of the action and the prompting unnecessarily complicated. Place the instrument in the dent's right hand and manually move it to her lips. With your left hand, raise your own instrument to your mouth, draw in air, and blow into the instrument. Blow softly if the student reacts negatively to loud noises. Reward the student even if she only holds the instrument against her lips, for a partial imitation is a good start. Repeat this step until sound, no matter how feeble, is heard from the instrument. From this point on, use the technique of shaping to build stronger blowing. If the student's blowing is slow in coming, you may want to introduce novel instruments to help maintain her motivation. When the student can make sound with the instrument, discard your own instrument and demonstrate blowing without it. Let the student continue to blow into her instrument. When the student's sound is strong, fade her instrument and keep it as a reinforcer for blowing without it. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses.

If musical instruments are ineffective as prompting devices, try blowing tiny pieces of tissue paper placed in a large shallow bowl. We suggest postponing teaching imitation of blowing bubbles or blowing out a lit candle because these actions require the student to aim at a small target in addition to blowing with certain strength in order to succeed, which may result in frustration rather than success.

If the student has difficulty opening her mouth, use a variety of the student's favourite foods for prompting mouth movements. This may be done by holding the student's favourite food (e.g., cookies) in front of your mouth and saying, 'Do this,' while opening your mouth wide and taking a bite of your cookie while moving another cookie toward the student's mouth. If the student opens her mouth just a tiny bit, praise her instantly, and then give her a bite of the cookie. Holding the cookie somewhat above the student's mouth instead of directly in front of it may facilitate her opening her mouth wider. Repeat this step for several trials. Begin fading this prompt by discarding your cookie but keeping hers and use differential reinforcement for further shaping of a wide-open mouth. Probe to see if the cookie can be faded as a prompt while keeping the cookie as a reinforcer for the student opening her mouth. Then fade the sight of the cookie altogether. Once mastery is reached (5 out of 5 or 9 out of 10 unprompted correct responses), return to the next step in the main program section.

If the student has difficulty sticking out her tongue, help to remedy this by using one of the student's favourite 'licking' foods (e.g., lollipop, Popsicle, cotton candy, ice cream cone, jam placed on the tip of a Popsicle stick). A lollipop is used in this example. Tilt your head forward a little so the student can easily catch sight of your tongue when it moves out of your mouth. Say, 'Do this,' stick your tongue out as far as you can, move the lollipop up, and lick it. Simultaneously move the student's lollipop up for her to lick. As soon as the student's tongue sticks out a tiny bit, reinforce her by moving the lollipop to her tongue for a lick. Repeat this step while gradually fading your lollipop but keeping the student's and use differential reinforcement for further shaping of the imitation. Then fade the student's lollipop as a prompt but continue to use it as reinforcement. Finally, change the reinforcer to something that would not be used as a prompt for licking. Set mastery at 5 out of 5 or 9 out of 10 unprompted correct responses. Once this behaviour is mastered, return to the next step of the main program section.

Chaining Two-Part and Three-Part Imitations

Up until now the student has learned to attend to and imitate single behaviours. From the following sections, the student is taught to imitate two and later three behaviours in a chained sequence. This is often a difficult task, but it is essential to establishing complex behaviours. You may take some comfort in knowing that once this technique is mastered, it can be used in the teaching of many subsequent programs (e.g., learning to follow complex instructions involving several parts, such as 'Close the door, then turn on the light, and sit down'). For younger students, one goal of teaching the imitation of chains is for the student to eventually attend to other children playing and imitate them in parallel play and in play interaction. It is impossible to separately shape the various and complex behaviours the student needs to learn in order to play with other children. However, the student can be taught to imitate chains of behaviours, a skill that enables him to later imitate chains of novel behaviours demonstrated by his peers.

The following prerequisite skills and stepwise procedures facilitate the acquisition of chaining tasks and should be followed closely: (1) the student should have mastered at least 50 single gross and fine motor imitations. (2) The student should have mastered the imitation of the separate behaviours that compose particular two- or three-part imitations. (3) There is some reason to believe that mastery of tasks that require the student to attend to a series of stimuli can facilitate mastery of two-and three-part imitations. These tasks are presented in the Matching and Sorting Program (Chapter 12) and the receptive language programs (Chapters 15, 17, and 18). Examples include matching rows of visual stimuli and retrieving several objects when instructed to do so.

In chaining, once the student engages in one response, this response provides the cue for him to engage in a second response. For example, if you demonstrate putting a block in a bucket (SD1) immediately followed by tapping a drum (SD2), the student must learn to imitate SD1 which in turn cues R2. The fact that such a response requires learning is evidenced by the observation that when the teacher demonstrates two behaviours in a row to students who have learned to imitate only single behaviours, these students typically imitate R2 and skip Rl. Most likely, these students imitate the teacher's presentation of SD2 because that stimulus is the most recent one and hence the most likely one for them to respond to. Part of the task becomes one of teaching the student to respond to the temporal ordering of the teacher's two behaviours (responding with Rl be-fore R2).

To facilitate the acquisition of chained imitations, start with chains that consist of two short and maximally different in-the-chair behaviours (e.g., imitating putting a block in a bucket, then tapping a drum). For some students, it may be more effective to first teach the chaining of gross motor behaviours as opposed to behaviours involving objects. If you decide to start by using gross motor behaviours without objects, begin with two behaviours related to body parts that are relatively far from one another (e.g., imitating tapping head, then stomping feet). Such behaviours should be easier for the student to attend to (discriminate) than two behaviours that involve body parts in close proximity to one another (e.g., imitating touching neck, then touching shoulders).

After a few short in-the-chair chains are mastered, introduce chains consisting of one short and one longer in-the-chair behaviour (e.g., imitating throwing paper into the wastebasket, then building a pretend tower out of blocks). Once the student masters a number of such chains, go on to chains consisting of two relatively long in-the-chair behaviours (e.g., imitating completing a four-piece shape puzzle, then stacking rings on a ring stacker). Once the student masters the imitation of several in-the-chair chained behaviours, introduce chains consisting of one in-the-chair behaviour and one out-of-the-chair behaviour, again starting with the imitation of two short behaviours (e.g., imitating closing a book, then putting it on the shelf) and then gradually moving on to responses that require longer periods of time to complete. Finally, teach the imitation of two out-of-the chair behaviours, again starting with two short behaviours (e.g., turning off a light, then putting a ball into a toy basketball hoop) before teaching the imitation of two longer and more complicated behaviours.

Procedures demonstrating how to teach two-part chains follow.

Two-Part Imitations

We illustrate the following procedures using a two-part chain consisting of having the student imitate you tapping your head and then stomping your feet. In the steps that follow, the student should sit facing you (no table is needed). Let SD1 be your demonstration of tapping your head and R l be the student's correct imitation of SDL Let SD2 be the demonstration of stomping feet and R2 be the student's imitation of SD2.

Phase 1

► Step 1

Present SD1, which consists of saying, 'Do this,' while tapping your head. Prompt R l if necessary. While the student is engaged inRl, present SD2 (stomping feet). Thus, while the student taps his head, you should remove your hand from your head, place your hand in your lap, and quickly present SD2 (stomping feet). It may be necessary to manually prompt the student's stomping his feet. If a manual prompt is needed, fade it over the next few trials. Do not reinforce the student until both R l and R2 are completed.

Note that there is an overlap between the two imitations (R l and R2, tapping head and stomping feet). This is referred to as a response overlap, which functions as a prompt because it prevents the student from performing only R2 when both SD1 and SD2 are presented in a sequence. Stated differently, the prompt allows the student to engage in the R1-R2 sequence, which then can be reinforced and strengthened.

Once the manual prompt is faded, fade the response overlap prompt by decreasing the time interval between the presentations of SD1 and SD2. That is, initially say, 'Do this,' while tapping your head and then, when the student just begins to tap his head, quickly go on to stomping your feet. Next, begin fading the prompt by, for example, stomping your feet as the student lifts his hand to touch his head. If you fade the response overlap prompt too quickly, the student will skip R l and emit only R2. If this occurs, go back and reinstate the minimal amount of response overlap necessary to restore R l, eventually demonstrate both behaviours before the student begins either of his responses. Remember to probe unprompted trials so as to decrease the number of prompted trials, if possible. Place mastery at 5 out of 5 or 9 out of 10 unprompted correct responses.

When you demonstrate SD1 followed by SD2 without a delay and the student responds correctly with R l and R2, a new SD and a new R are created. The new SD is the SD1SD2 combination, and the new R is the R lR2 chain. Once the student masters the first chained two-part imitation, consider this to be a major and significant achievement. We recommend that this mastery be strengthened by all team members and practiced across different environments before the second chain is introduced. To help maintain the student's motivation, keep the teaching sessions short and intersperse other programs, such as Matching and Receptive Identification of Objects, between sessions of Nonverbal Imitation.

The response overlap prompt may help most students achieve mastery of chained imitations, but it may not be sufficient for all students. If the student continually responds with R l and does not go on to complete the chain with R2, use a visual or verbal prompt as follows: Present the SD1-SD2 stimulus. If the student responds with R l and then stops, wait for a moment, thereby giving the student a subtle prompt of expecting her to go on to R2. If this prompt fails, repeat the trial using a stronger prompt, such as looking at the student's feet, pointing to them, manually moving them, or whispering, 'Stomp feet' (if the student has mastered this instruction). Remember to reinforce prompted trials, otherwise the student will eventually stop imitating and may tantrum. The student's favourite reinforcers, however, should be saved for unprompted trials.

It is sometimes difficult to fade the overlap prompt because the student may start R l as soon as you present SDL The student, however, must learn to wait while you complete the SD1SD2 sequence. This may require some additional prompting. The simplest procedure for teaching the student to wait while you demonstrate a two-part behaviour is to choose chains that can be demonstrated with one hand. With one hand free, you can hold the student's hands in his lap while presenting the SD combination. For example, while presenting the SD1-SD2 combination, place your right hand over the student's hands in his lap, preventing him from engaging in R l. With the completion of SD2, let go of the student's hands to allow him to engage in the R1-R2 chain, giving him a slight physical prompt if necessary.

► Step 2

You may anticipate that, as the student masters responding to the SD1-SD2 combination with R lR2, this response may not be the same as imitating the SD1-SD2 combination. Such an occurrence may be observed if you demonstrate any behavioural combination and that combination triggers the R1-R2 chain. To help prevent this, you should establish another chain to be imitated (e.g., raising an arm, then tapping a knee) and then intermix these two chains as well as additional chains as done in discrimination learning. Suggestions for new two-part imitations are provided in the following list.

Additional Two-Part Body Imitations SD 'Do this'

raising an arm, then tapping a knee

touching an elbow, and then raising a foot

crossing legs, then tapping tummy

folding arms, then waving

touching ears, then rocking from side to side

touching back, then touching feet

touching neck, then crossing ankles

'drinking,' then touching shoulders

holding up a hand in a 'stop' gesture, then stomping one foot

blowing, then shading eyes with one hand

raising both arms, then clapping

opening mouth, then stretching arms to sides

sticking out tongue, then wiggling fingers

folding hands, then making a fish mouth

Phase 2

Slowly increase the difficulty of two-part imitations by introducing two-part imitations in which one imitation is conducted in the chair and the other is done out of the chair. Examples of such two-part imitations are given in the following list. These chains should be taught by following the teaching procedures described in the section 'Two-Part Imitations.' When teaching chains that contain out-of-chair behaviors, call the student back to the chair after each chained response in order to keep him focused.

In-Chair, Out-of-Chair Two-Part Imitations SD 'Do this'

standing up, then walking around a chair

blowing nose, then throwing tissue in a wastebasket

drinking juice, then putting on shoes

looking at a book, then putting the book on a shelf

doing a simple puzzle, then putting it away on a shelf

scribbling on paper, then putting crayons in a drawer

putting blocks in a bin, then walking over to sit on the couch

stringing two beads, then crashing two cars on the floor

putting five beans into a bottle, then opening a door

Once mastery is achieved in Phase 2, introduce two-part imitations containing two out-of-chair behaviours. Follow the same teaching procedures described in Phase 1. Call the student back to the chair after each two-part chain in order to keep him focused.

Out-of-Chair, Two-Part Imitations SD 'Do this'

turning off a light, then shooting a basket

closing a door, then jumping on a trampoline

throwing a beanbag over a chair, then turning on the radio

shooting a basket, then walking around the room

picking shoes up from the floor, then putting shoes in the closet

getting a pile of blocks, then building a tower on the floor

knocking the tower down, then putting the blocks in a bin

getting a doll from a crib, then feeding the doll on the couch

doing a somersault, then jumping on a trampoline

getting a cup from the kitchen, then setting it on the table

Maintenance and Generalization

Once the student masters approximately 15 two-part imitations, transfer the first 10 and most frequently practiced chains to a Maintenance Schedule. Review maintenance chains as often as necessary to keep them mastered. Generalize chains across teachers and to everyday environments. It is particularly important to practice and generalize imitations that are functional for the student. One by one, introduce novel two-part imitations to the Current Schedule and move mastered and frequently practiced chains to the Maintenance Schedule.

Three-Part Imitations

Given that the acquisition of three-part imitations is difficult for most students, you should plan ahead; combining behaviours the student is most likely to master. We recommend that the following prerequisite skills be mastered before introducing three-part imitations: (1) the student should be proficient at chaining novel two-part imitations (i.e., two-part chains not specifically taught) and should have achieved mastery of 30 to 40 two-part chains. (2) The student should have mastered 20 to 30 single imitations that will compose the first three-part imitations to be taught. (3) The student should have mastered a number of receptive language programs (and expressive programs if the student is verbal), including identification of objects, colours, shapes, letters, and numbers; single and two-part receptive instructions; and prepositions.

Three-part imitations should be taught by following the same procedures described for teaching two-part imitations. If the student does not make progress in learning the first three-part imitation after 1 week of practice, temporarily place this format of the Nonverbal Imitation Program on hold. It may be reintroduced at a later stage in teaching.

Before beginning to teach three-part imitations, remember that it is easy to get carried away when teaching programs like the Nonverbal Imitation Program because many students excel in such programs. However, it is just as important to broaden the student's curriculum as it is to teach specific skills within certain programs. Suppose the student is 6 months into the treatment program by the time two-part imitations are mastered. In this case, the student may also be involved in programs ranging from Early Play Skills to Early Abstract Language, skills that may be of more benefit to the student than further advances in imitation at this time.

Three-Part Imitations SD  'Do this'

emptying out a puzzle, then completing the puzzle, and then putting it away

getting a cup, then sitting down, and then pouring juice into the cup

getting a car, then driving it down the garage ramp, and then parking the car in the garage

building a tower, then knocking it down, and then putting the blocks into a bin

taking off shoes, then taking off socks, and then sitting down on the couch

blowing, then clapping, and then crossing legs

touching head, then touching knees, and then touching toes

waving, then stomping feet, and then folding arms

jumping, then pointing to nose, and then sitting down

pretending to cry, then pointing to teeth, and then folding hands

standing up, then walking around a chair, and then sitting down

marching, then flapping arms, and then turning on a light

Maintenance and Generalization

Follow the same procedures for maintaining mastery of three-part imitations that are suggested for the maintenance of two-part imitations. Generalize functional chains to everyday situations when appropriate.

Concluding Comments

As progress is made in teaching the student to chain imitative behaviours, you make an important step toward extending nonverbal imitation into meaningful, everyday behaviours. We illustrate this extension by presenting programs for teaching art and pre-academic skills in the Arts and Crafts Program (Chapter 20) and reading and writing skills in the Reading and Writing Program (Chapter 29). Nonverbal imitation also forms a basis for acquiring play skills (see Chapter 19) and self-help skills (see Chapter 21).