A comparison of prompting hierarchies on the acquisition of solitary play and vocational skills

The present study compared two variations of a 2-second delay prompting hierarchy on the acquisition of solitary play and vocational skills. The most to least with a 2-second delay hierarchy (MTL 2 s delay) instructed with fading physical prompts. A simplified version, referred to as manual guidance with a 2-second delay (MG 2 s delay), instructed with a static prompt and constant time delay. All participants acquired the play and vocational tasks, and the rate of acquisition was comparable for all tasks taught in both conditions. The rate of acquisition was similar between fading prompts and not fading prompts while maintaining a constant time delay. 7 A Comparison of Prompting Hierarchies on the Acquisition of Solitary Play and Vocational Skills There is widespread awareness of autism spectrum disorders (ASD) around the globe. Early treatment of ASD will have more favorable results than will treatments that occur later. One of these treatments, applied behavior analysis, has been shown to ameliorate the symptoms of ASD (Myers & Johnson, 2007). Moreover, Lerman, Vorndran, Addison, and Kuhn (2004) determined that most typically developing children can understand classroom work solely with teacher instruction, materials, and occasional social reinforcement. Contrarily, MacDuff, Krantz, and McClannahan (2001) discovered that teacher instruction combined with task materials may not be enough for learning to take place in people diagnosed with ASD. However, certain learning cues, such as prompts, can enable people diagnosed with ASD to learn new skills (MacDuff et al., 2001). Prompts are auxiliary antecedent stimuli that can take many forms, such as physical guidance, gestures, models, or verbal cues (Green, 2001). When prompts are used as a teaching tool, fading them becomes necessary to encourage independence (Lerman et al., 2004). Prompting procedures should continue to be evaluated to facilitate the greatest potential of learning. Behavior chains are sequences of responses in which each response produces a stimulus change that functions as conditioned reinforcement for that response and as a discriminative stimulus for the next response in the chain. Chains can include almost anything from brushing one's teeth to building a structure with blocks. The process of breaking these chains into smaller, teachable units is called task analysis (Cooper, Heron, & Heward, 2007). Task analyses are used to teach behavior chains, and Spooner and Spooner (1984) concluded that task analyses may 8 produce better learning by examining and testing the different prompting variations used within the task analysis. Prompts are supplementary antecedent stimuli used to occasion correct responding in the presence of a discriminative stimulus that will eventually control the behavior (Cooper, Heron, & Heward, 2007). Response prompts operate directly on the response, and can involve verbal instructions, modeling, or physical guidance (Cooper, Heron, & Heward, 2007). In a review study, Demchak (1990) concluded that the use of response prompts can increase the probability that a particular behavior will occur, and, therefore, can provide more opportunities for differential reinforcement of that behavior. It is important that prompts be faded, so that the response is occasioned by natural cues. Billingsley and Romer (1983) agreed that learned behaviors should eventually exist in the presence of natural stimuli and be maintained by natural consequences, and that stimulus control should be shifted from the prompt to the naturally occurring stimulus using some type of prompting hierarchy. Wolery and Gast (1984) defined four procedures for transferring stimulus control from response prompts to natural stimuli. These procedures are most-to-least prompts, least-to-most prompts, graduated guidance, and time delay. Most-to-least prompts involve gradually reducing the amount of physical assistance provided as training progresses from trial to trial and session to session. Least-to-most prompts involve giving the participant an opportunity to perform the response with the least restrictive prompt on each trial. The participant receives greater degrees of assistance until a correct response is emitted. Graduated guidance involves providing as needed assistance that is immediately faded out to transfer stimulus control; and time delay uses variations in the time intervals between the presentation of the natural stimulus and the presentation of the response prompt. The two types of time delay are progressive and constant. 9 Progressive time delay starts with a zero-second delay between the presentation of the natural stimulus and the response prompt, and this delay is gradually and systematically extended. Constant time delay applies a fixed time delay between the presentation of the natural stimulus and the presentation of the response prompt (Cooper, Heron, & Heward, 2007). Wacker and Berg (1984) transferred stimulus control using prompts when they taught complex vocational sequencing tasks to intellectually disabled adults using picture prompts. Horner and Keilitz (1975) also showed that prompting in the form of verbal instruction, modeling, demonstration, and physical assistance played a vital role in developing improved toothbrushing behavior in eight participants. Schleien, Wehman, and Kiernan (1981) demonstrated that the use of prompts and social reinforcement allowed for three intellectually disabled participants to learn an age-appropriate darts game. Griffen, Wolery, and Schuster (1992) discovered not only that many independent living skills desired for the intellectually disabled population are chained tasks, but that the use of constant time delay procedures combined with social reinforcement was effective at teaching chained cooking skills. Steege, Wacker, and McMahon (1987) contrasted the traditional least-to-most prompting sequence with a prescriptive method that involved providing the participant with a level of assistance that had previously been sufficient to occasion responding according to behavioral assessment data. It was concluded that although the prescriptive sequence was more efficient than the traditional least-to-most sequence, both procedures were equally effective. Given the complex procedure of the presciptive sequence and its difficulty of implementation, it was also suggested that the least-to-most sequence was more practical. Demchak (1990) reviewed research on fading prompts. Four methods of fading prompts were defined as (1) least-to-most, (2) most-to-least, (3) graduated guidance, and (4) time delay. 10 Demchak (1990) concluded from several articles that most-to-least prompting appeared more efficient than least-to-most prompting when looking at the rate of response acquisition to teach a variety of different skills. It was also concluded from numerous studies that constant time delay is equally as effective as progressive time delay and easier to implement (Demchak, 1990). Miller and Test (1989) determined that most-to-least was equally effective as constant time delay, constant time delay was more efficient than most-to-least prompting in terms of instructional time and number of errors. McDonnell and Ferguson (1989) made an opposing conclusion that both most-to-least was more efficient than constant time delay. Several studies are in agreement that both most-to-least and constant time delay are more effective than least-tomost prompting. McDonnell (1987) concluded that constant time delay was more effective than least-to-most prompting when teaching four severely handicapped high school students to purchase items from a convenience store. Findings of Schoen and Sivil (1989) indicated a small but noticeable advantage of using constant time delay rather than least-to-most prompting. Additionally, the use of time delay was more efficient than least-to-most prompting in terms of the rate of acquisition (Bennett, Gast, Wolery, & Schuster, 1986). Doyle, Wolery, Gast, and Ault (1990) conducted an investigation leading to the conclusion that constant time delay was superior to least-to-most prompting in that constant time delay resulted in decreased instructional time, as well as fewer trials to criterion and errors. Libby, Weiss, Bancroft, and Ahearn (2008) compared most-to-least and least-to-most prompting on the acquisition of solitary play skills. Some participants failed to learn with the least-to-most procedure, and the most-to-least sequence was more effective and resulted in fewer errors than least-to-most. With the addition of constant 2-second time delay to the most-to-least sequence, response acquisition was faster than the most-to-least sequence without a delay, even 11 though more errors occurred. It was concluded that the use of MTL 2 s delay is the best default prompting strategy, and that individual differences are expected to occur among learners (Libby et al., 2008). Prompts are only as valuable as their ability to successfully transfer stimulus control to the natural stimulus. Most prompting strategies used today are successful at transferring stimulus control, but some strategies are easier to implement than others. Most research on prompting today continues to focus on discovering easier, more efficient, and more effective ways to teach behavior chains. Demchak (1990) stated that procedures leading to task mastery sooner should preferably be used. Libby, Weiss, Bancroft, and Ahearn (2008) concluded both that the most-toleast procedure was more effective than the least-to-most procedure and that the most-to-least procedure was more efficient when paired with a constant time delay. Prompting procedures involving fewer prompts are also likely easier to implement. Therefore, a simpler version of a MTL 2 sec delay prompting strategy with a static prompt paired with a constant time delay might be easier to implement and be as effective as the MTL 2 sec delay prompting strategy that fades physical prompts.