Applied Behavior Analysis (ABA) utilizes an array of scientifically proven interventions and techniques to help students with autism spectrum disorders (ASD). When administered by a qualified ABA therapist, ABA can help students achieve positive behavioral change and develop functional life skills.
Two of the most common ABA methodologies are Discrete Trial Training (DTT) and Natural Environment Training (NET). Some therapists choose to utilize one or the other exclusively, while many opt for a hybrid of both.
So how do ABA therapists choose when to employ either DTT or NET? They each require data-driven decision-making and facilitation by expert clinicians, but in action, they look quite different. The choice between the two has the potential to be as complex as the student needs they serve.
The Pros and Cons of Discrete Trial Training
Discrete Trial Training (DTT) is one of the most common ABA intervention techniques. Students complete very structured and controlled tasks quickly and repeatedly. These discrete trials follow a predictable design that allow for this type of standardization of practice and ease of repetition (Cosgrave, 2017).
A trial begins with an antecedent. This can be some combination of verbal and nonverbal stimulus to draw out the desired response from the student. In most cases, this antecedent is then followed up with a prompt. A prompt could be a gesture where the desired result is modeled by the teacher or a partial gesture where the teacher directs the student toward the desired result without actually modelling the it.
Following the antecedent and any teacher prompting, the student is expected to respond in a specific, targeted manner. Should the student complete their task successfully, they receive positive reinforcement (praise, food, token, toy, etc.). Should the student fail to complete their task successfully, the teacher corrects him or her and no reinforcement is given. Typically, a new trial begins immediately thereafter.
DTT relies on the core tenets of behavioral psychology to promote positive changes in student decisions, actions, and skills. As such, DTT is backed by a plethora of scientific research touting its effectiveness with many students dealing with autism and related disorders. That said, it also has some notable limitations:
Pros of Discrete Trial Training
Conducting multiple trials with fewer variables can lead to large data sets and informative results. Since trials happen in a controlled learning environment with limited external stimuli (like in a classroom or clinical space), therapists can conduct a large number of trials in a short period focused on producing controlled, actionable data.
Training can happen with other students. DTT can be adapted well to a small group setting, which adds to social learning opportunities — a particularly important skillset for students with autism spectrum disorders (Rotheram-Fuller, et al., 2008).
DTT promotes increased attention skills (Wong, et al., 2007). With DTT, consequences and reinforcement cycles are both timely and predictable for students. Tasks, prompts, and student responses are all expected to be quick and focused to limit the potential for distraction. The routine-based learning situation helps promote key student skills like working in place, sustained effort, and focus (Din & McLaughlin, 2000).
It’s vocal. The use of concise verbal cues (often combined with visual cues) are especially effective for language learners (Jones, et al., 2007).
Complex tasks that would otherwise be exceedingly difficult for a student can be effectively broken into smaller trials. ABA therapists can use DTT to workshop each individual step of a process, gradually adding more or combining them based upon the data from trial outcomes.
Cons of Discrete Trial Training
There is a lack of authenticity. Students are given contrived tasks and reinforcements rather than allowing the learning process to be student-driven.
DTT requires extra efforts to help promote optimal generalization and discrimination (Steege, et al., 2007). The reliance upon a set and controlled learning environment means transfer trials are required for students to carry developed skills into their real life settings (Cowan & Allen, 2007). For example, a student who can identify a car presented as a picture or toy during a DTT session will need additional training to be able to identify a full-sized car in the real world. Variables like size, color, shape, and model could all be potential hurdles.
DTT is heavily prompt reliant (verbal, partial-verbal, physical, partial-physical, hand over hand). This requires ABA therapists to fade the prompts over time in order to ensure the skills can translate to the student’s natural environment (Schreibman, et al., 2015).
DTT can exclude other helpers. It can be difficult to include untrained adults, siblings, or age-level peers in the DTT process due to the rigid procedural structures required for effective outcomes.
The Pros and Cons of Natural Environment Training
Natural Environment Training (NET) is, as the name implies, a more true-to-life approach to ABA therapy. At its core, student interests, not therapists’, guide the activities, pace, and reinforcements used to produce growth.
Much like DTT, NET involves teachers using antecedents and prompts to elicit targeted responses from students. However, with NET, teachers use the student’s environment to identify relevant motivators and reinforcers. Targeted behaviors and responses are modeled in relevant real-world contexts to elicit the suitable responses (Sundberg & Partington, 1998).
One of the defining characteristics of NET is that students can literally be learning anywhere and anytime. This adds an extra logistical layer for ABA therapists to consider as they are accomplishing much of the same data collection as they would be with DTT, just outside the confines of a controlled learning environment. ABA therapists who practice NET typically carry some combination of clipboards, clickers, and/or electronic devices so that they can track students’ behaviors and progress towards their targets wherever they may occur.
While the NET method is inherently less rigid and structured than DTT, it better contextualizes the learning experience into the student’s world. This increased authenticity makes it easier for students to create connections between therapeutic practice and their environment (Cowan & Allen, 2007).
Pros of Natural Environment Training
Reinforcers and consequences are authentic and come from both the environment and the student’s expressed interests.
It relies on natural and functional stimuli rather than contrived trials. This means teachable moments can be acted upon on the spot and learning can happen at a student-directed pace (Sundberg & Partington, 1998).
NET allows family members and peers to become active participants in training, as they are part of the student’s natural environment (Schreibman, et al., 2015). This integration of social involvement is crucial for students with ASD (Rotheram-Fuller, et al. 2008).
NET is conducive to generalization and discrimination. Students learn new concepts in the relevant environments and situations increasing the likelihood of retention and future skill application (Schreibman, et al., 2015).
Cons of Natural Environment Training
Data collection can end up being more logistically difficult than with DTT sessions due to an increase in potential variables like environment and access to materials. Teachers need to be equipped with the tools they need to take advantage of teachable moments.
There is a chance for increased distractions and decreased student focus since learning is taking place in less controlled and more unpredictable settings than in a traditional DTT session.
Trials often lack a single, targeted outcome. ABA therapists, not just students, must be focused in potentially distracting environments to ensure accuracy.
Making the Decision between DTT and NET
The debate between Discrete Trial Training and Natural Environment Training is one that elicits passionate support on both sides. Each style has its positives and negatives. However, just as with most aspects of ASD education, there can be value in a blended approach (Geiger, et. al. 2012).
While DTT has features that are optimized for school and clinical environments, NET can take place anywhere and anytime during a student’s day. DTT provides students with controlled opportunities to hone in on specific skills with a high number of trials. On the other hand, NET is much more unpredictable, but offers students opportunities for generalization and an authentic application of the skills they intrinsically self-select. Between the two approaches, there is an opportunity for substantial differentiation and customization.
Herein lies the value of trained and certified ABA professionals. Under the supervision of accredited Board Certified Behavior Analysts, high quality ABA therapists engage in ongoing conversations about these pros and cons on behalf of students and with their families in order to elicit the most positive behavioral change possible.
Be sure to check out this article "ABA Therapy for Autism" by Autism Parenting Magazine for a look at other methods used in ABA.
Cosgrave, G. (2017). Discrete Trial Training. Retrieved November 10, 2017, from http://www.educateautism.com/applied-behaviour-analysis/discrete-trial-training.html
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Sheldon Soper is a New Jersey middle school teacher with over a decade of classroom experience teaching students to read, write, and problem-solve across multiple grade levels. He holds teaching certifications in English, Social Studies, and Elementary Education as well as Bachelor's and Master's degrees in the field of education. In addition to his teaching career, Sheldon is also a content writer for a variety of education, technology, and parenting websites including Teach.com. You can follow Sheldon on Twitter @SoperWritings and on his blog.