Preference assessments and reinforcer assessments increase the likelihood of effective interventions, and they are simple to implement routinely in your ABA program. Reinforcers play a vital role in the success of any ABA behavior reduction or skill acquisition plan. A reinforcer is any stimulus that follows a behavior and makes that behavior more likely to occur in the future. As learners with autism often have limited interests and social reinforcers are often insufficient as a reinforcer, you must intentionally evaluate reinforcers used in your interventions. Identifying child-specific reinforcers requires conducting either a reinforcer assessment or a preference assessment.
Preference for objects and activities is often fluid, changing due to satiation, time of day, environmental or other factors. A diverse assortment of potential reinforcers offers the greatest opportunity for effective intervention. Reinforcer and preference assessments provide valuable insight into the motivation of your learner. Reinforcer and preference assessments differ in what they measure. Preference assessments test the learner’s interest in objects or activities to identify potential reinforcers and reinforcer assessments measure the effects of utilizing those items or activities as reinforcers.
Utilizing effective reinforcers during teaching reduces maladaptive behavior while increasing the accuracy of responding (Mason, McGee, Farmer‐Dougan, & Risley, 1989). Before going on, learn more about the importance of an effective reinforcer in our article: Characteristics of an Effective Reinforcer in ABA.
Difference Between Reinforcer Assessments and Preference Assessments
Although both a reinforcer assessment and a preference assessment strive to identify effective reinforcers, there’s a distinct difference between the two. Preference assessments identify stimuli as potential reinforcers while reinforcer assessments determine the effectiveness of those stimuli as reinforcers.
Essentially, you use the preference assessment prior to implementing reinforcement. You then collect data on the effects of that reinforcer during implementation and use that data to conduct the reinforcer assessment. While it’s unlikely you will need to conduct a reinforcer assessment in your daily practice, here are some of the basics. When conducting a reinforcer assessment you:
- Compare 2 or more reinforcement conditions to compare the rates of responding
- Use concurrent, multiple, or progressive-ratio schedule of reinforcer assessment
A reinforcer assessment offers some clear answers as to ranking reinforcers in terms of effectiveness or determining the demand threshold for reinforcer effectiveness. While these assessments may be used in research or under controlled conditions, they are impractical for daily use. Focus your attention on understanding preference and preference assessments unless presented with a valid reason for taking the time away from intervention to conduct a reinforcer assessment.
Establishing Operations (EOs)
Preference for stimuli shifts over time in relation to several different variables related to establishing operations (EOs). EOs are environmental variables that impact the effectiveness of a specified stimulus as a reinforcer at a given time (Cooper, Heron & Heward, 2007). An EO affects the reinforcer by either increasing or decreasing its value at any given moment.
When the effect is an increase in effectiveness of the reinforcer, we refer to it as a motivating operation (MO). When the effect is a decrease in effectiveness, we call it an abolishing operation (AO).
Establishing operations are helpful in understanding why reinforcers become more or less effective at different times. Keep in mind that these effects are constantly changing. To ensure effective reinforcement, alter the reinforcers used based on the establishing operations in effect at that moment.
Look at this example:
You want to determine the potential of using juice as a reinforcer with your client Kevin. You conduct your first preference assessment after he has breakfast, a smoothie with vitamin supplements. During this assessment, he demonstrates low motivation for juice and seems to prefer a toy truck. You conduct a second preference assessment after a morning snack of pretzels. This time, he seems much more motivated for the juice. You use the juice as a reinforcer during several trials, but Kevin grabs the bottle and downs most of the bottle before you grab it from him. During the next trials, Kevin’s motivation is very low. Why the difference in motivation?
The answer is EOs.
- The smoothie Kevin had for breakfast served to have an abolishing operation (AO) for juice. The smoothie was filling and quenched his thirst. He didn’t want more to drink after the smoothie.
- The pretzels served as a motivating operation (MO) because they made him thirsty. A salty snack increases his motivation for something to drink.
- Drinking a large amount of the juice was another abolishing operation (AO). He became satiated and no longer wanted juice.
You can use establishing operations to your advantage when you understand them. Withholding access to a preferred item creates a sense of deprivation. Granting access to that item starts the process of satiation. How quickly satiation and deprivation impact motivation depends on the individual and their level of preference for a stimulus.
Gottschalk, Libby, & Graff, (2000) conducted a study that evaluated the effects of satiation and deprivation on preference assessment outcomes. To establish satiation, they allowed free access to the item for just 10 minutes prior to the assessment. To create a sense of deprivation, they withheld access to the item for 48 hours prior to the assessment. As expected, satiation resulted in decrease motivation for an item, and deprivation increased motivation. The amount of time required for satiation and deprivation varies depending on the child and the specific item, but they play a critical role in motivation.
Types of Preference Assessments
There are several options when trying to identify potential reinforcers. The following list is presented in a loosely ranked order from least intrusive/time consuming to more intrusive/time consuming.
While it may sound obvious, many times we simply forget to ask either the client or stakeholders (i.e. parents, teachers, etc.) what the child likes. Parents who have a solid foundational understanding of ABA may be able to tell you what they use as reinforcers. Other times, parents might give you clues about what the child likes and with a few more questions, you may be able to uncover some strong reinforcers. Take note when parents say they don’t allow their child access to something or when they refuse to restrict access to something because of the behavior it provokes. This might demonstrate a strong preference for an item or activity. Offer to work with the parents to help them overcome the behavior. Often simply by making the item or activity contingent on performing some behavior this intense reaction diminishes.
Use a questionnaire to help parents think of preferences they might not normally consider. The ABA Institute includes a Reinforcement Inventory for both children and adults in their Behavior Assessment Guide. This inventory provides an extensive list of potential reinforcers and allows caregivers to describe how reinforcing an item might be on a Likert scale.
Many children can verbalize what they like. Try asking open-ended questions, offering choices or asking them to rank order some of the things they like. They may come up with simple ideas you had never thought about. Alternatively, they may suggest items or activities that are too big or impractical to use. When this occurs, make some alternative suggestions or choose a behavior that is worth the value of their suggested item or activity.
Here’s a real example:
An 8-year-old told his parents he wanted an expensive toy (one worth $50 that his parents were considering buying for his birthday). His parents often had difficulty telling him no because of his intense reaction (he often became aggressive and threatening). They told him he could have the toy but first he had to sleep in his own bed 7 nights in a row.
For his parents, it was a win-win solution. If he refused, they could save the toy for his birthday. If he slept in his own bed, it was well worth the investment to them. In the end, he slept in his bed for 7 nights and after establishing this routine, he rarely asked to sleep in his parents’ bed and accepted being told he needed to sleep in his own room.
Free Operant Preference Assessments
According to Cooper, Heron and Heward (2007), “the activities that a person engages in most often when able to choose freely from among behaviors will often serve as effective reinforcers when made contingent on engaging in low-probability behaviors.” What this means is if you pay attention to what a child does when given the chance to do anything, those behaviors he engages in can serve as reinforcers. This is a free operant observation.
During a free operant observation, the child has unlimited access to anything available in the environment. You can create a contrived free operant observation by adding items to the environment that you suspect may be of interest to the child or you may choose to conduct a naturalistic free operant observation and only allow items natural to the environment. In either case, you will observe the total duration the child engages in each activity to arrive at a rank order.
A major benefit to free operant assessments is the ability to observe the child engage in stereotypic behavior. For some children, stereotypies hold some powerful reinforcing value. Many children can’t say that what they really want to do is engage in stereotypy. Often the only way to know this is to watch the child.
Check out this video to see how a contrived free operant observation is conducted:
Single Stimulus Preference Assessment
The single stimulus assessment is a trial-based assessment during which stimuli are presented one at a time. It is also referred to as the successive choice method of stimulus presentation during an assessment. Present each item one at a time in a random order and note the child’s reaction to the item. Does he accept or reject the item? Note how long he engages with each item. Each item should presented multiple times varying the sequence of presentation.
While this method offers a simple solution, it also provides limited information. You may be able to get some idea of level of preference when you collect data on how long the child engages with each item, but by the end of your assessment, the child may be satiated with his highest preferred items. This method of presentation may be best suited to reduce the number of items presented during a more structured assessment.
In this video, Kylie Lyons begins a paired choice assessment by presenting a single stimulus to determine the interest her client has in each item before including it in the more structured assessment:
Multiple Stimuli With/Without Replacement (MSW/O) Preference Assessment
Multiple stimuli with or without replacement provides a rank order of preference for the presented stimuli. When conducting these assessments, present an array of stimuli in random order and ask the child to choose 1 item. Allow the child a few moments to engage with the item before taking it and either returning it to the array (MSW) or removing it from the array (MSWO).
Through repeated presentation, the child selects his most reinforcing choices. The MSWO with as few as 3 items can provide you with a ranking of potential reinforcers (Carr, Nicolson, & Higbee, 2000).
Take a look at this video to see how to conduct an MSW:
Paired Choice Preference Assessment
A paired choice (also called paired stimulus or forced choice) assessment systematically presents all selected items paired with each other and alternating sides of presentation. This is the most time consuming of all of the preference assessments, but provides reliable information about the hierarchy of preferences for your client.
When you struggle to identify effective reinforcers for your client, it may be worth your time and effort to conduct this formal assessment; however, it can be confusing and difficult to run accurately. The below data sheet allows you to assess 5 items and shows in which position (left or right) the item should be placed. Circle the number corresponding to the number of the item selected and choose “N” for no response or no selection (if the child grabs both items simultaneously). Find the total number of times each item was selected and then calculate the percentage to find your rank.
Check out this video about paired choice preference assessments:
Choosing Preference Assessments
With all of the options listed above, how do you choose the right assessment for your situation?
Cooper, Heron and Heward (2007) offer some advice in choosing an assessment:
- Pay attention to your client’s activities before the assessment to determine what EOs may impact the assessment
- Determine if it’s more important to identify a reinforcer quickly or more accurately
- Decide if you want an assessment that ranks different stimuli or if you prefer one that occurs more frequently to address changes in preference
- Use a brief assessment with a smaller array of stimuli when time is limited
- Consider using data from different assessment methods to obtain the most accurate results
Although there may be times when it makes the most sense to conduct a thorough, contrived assessment, research shows that frequent, brief assessments provide sufficient information to identify potential reinforcers. Roane, Vollmer, Ringdahl, Marcus, (1998) found that conducting a brief 5 minute free-operant assessment reliably identified potential reinforcers without the need for relying on more time-consuming methods like the paired-choice assessment.
Ensure the most effective use of reinforcers by routinely monitoring the effectiveness of reinforcers using reinforcer assessments. Regular systematic reinforcer assessments lead to reduced maladaptive behavior and higher correct responding (Mason, McGee, Farmer‐Dougan, & Risley, 1989). Reinforcer effectiveness occurs along a continuum rather than as distinct extremes (effective or not effective), thus these assessments provide a hierarchy of effective reinforcers. Three variations of reinforcer assessments allow for a thorough analysis of reinforcer effectiveness:
- Concurrent schedule
- Multiple schedule
- Progressive schedule
Concurrent schedule reinforcer assessments
Concurrent schedule reinforcer assessments compare the effects of two stimuli to determine which will produce the more desirable effect in responding and/or behavior reduction when presented as a consequence. The reinforcer that produces the highest rate of responses and/or lowest rates of maladaptive behavior is the more effective reinforcer.
- Use stimuli identified as potential reinforcers through preference assessments.
- Ensure the presentation of similar tasks and tasks of similar difficulties.
- When comparing the effectiveness of bubbles and slime as reinforcers, alternate the use of each reinforcer during a single DTT session, then compare the data collected on trials. If a higher rate of responding was observed during trials where bubbles were presented as a reinforcer, this is the more effective reinforcer.
Multiple schedule reinforcer assessments
Multiple schedule reinforcer assessments compare the effects of two stimuli across two separate sessions using the same schedule of reinforcement for the same behavior with a specific SD present that signals which reinforcer is available during that session. The more effective reinforcer is the one used in the session associated with the highest rate of responding.
- Use stimuli identified as potential reinforcers through preference assessments.
- Ensure minimal variation between sessions and distinct SDs to distinguish the availability of the reinforcer (i.e. color cards, images of the reinforcer, etc.).
- When comparing the effectiveness of a video on the iPad and an interactive game on the iPad, post an image of the learner’s favorite video on the wall next to the DTT space during the session where the video is available, and post an image of the learner’s favorite game on the wall next to the DTT space during the session where the game is available. Collect trial-by-trial data during each session. The session where higher responding occurred is associated with the more effective reinforcer.
Progressive schedule reinforcer assessments
Progressive schedule reinforcer assessments measure the breakpoint at which a reinforcer’s effectiveness declines. It compares the relative response effort a learner is willing to emit to gain access to a given reinforcer. The interventionist systematically increases the response required for the learner to achieve reinforcement, regardless of responding. The breakpoint occurs when responding declines. The more effective reinforcer is the one associated with the highest breakpoint (the highest rate of responding).
- Use stimuli identified as potential reinforcers through preference assessments.
- Plan the systematic progressive schedule (how often and how much will response effort required be adjusted). Maintain the same schedule across all test sessions.
- When comparing the effectiveness of swinging and jumping on the trampoline as reinforcers, systematically increase the response effort required to earn reinforcement (i.e. reinforcement after 5 trials, 10 trials, 15 trials, 20 trials, etc.). The reinforcer associated with the highest rate of responding is the most effective reinforcer.
Expanding Effective Reinforcers for Children with Autism
A number of children with autism have extremely limited effective, tangible reinforcers. Other children may be motivated by stimuli that are either not readily available, difficult to deliver, or contextually inappropriate. This might include activities such as jumping, running, screaming, or banging a hand on a hard surface. Other children may be limited to unhealthy edible reinforcers such as candy or chips.
For these children, frequent preference assessments and reinforcer assessments help identify current interests, but may lack practicality. Time may initially be better spent in attempting to expand their array of potential reinforcers.
Use pairing and the Premack Principle to associate existing reinforcers with other stimuli that may serve as more practical reinforcers. This often works best when the new reinforcer is somehow related to existing reinforcers, but that’s not always necessary. Here are some examples:
Pairing is the process of combining a previously identified reinforcer with a neutral stimulus to increase the value of the neutral stimuli. Leaf et al. (2012) found that having a preferred adult play with a neutral stimulus while the child observed led to greater preference for that item. This effect occurs similarly when a preferred stimulus is associated with a neutral stimulus.
Your client, Jimmy has demonstrated a preference for few potential reinforcers including running back and forth across the room and M&Ms. You often work with him in the library and have been repeatedly asked by the librarian not to allow him to run across the room. There is also a strict no food policy, but you have gotten consent to bring M&Ms into the library if Jimmy doesn’t run while he’s there.
You determine that Jimmy’s success in this environment depends on identifying a new potential reinforcer. As he has ready access to an iPad across environments, you feel this would be a practical reinforcer despite the fact he has shown no real interest in any of the apps on it.
You choose a bubble pop app for its simplicity. Each time Jimmy pops a bubble, you give him an M&M. Over the course of several weeks, you gradually reduce the rate of M&M delivery, yet you notice Jimmy reaching for the iPad more frequently. With more time pairing the iPad with a known reinforcer, you are able to eliminate the use of M&Ms and the iPad has become a powerful reinforcer.
The Premack Principle, also known as Grandma’s Rule or first/then, states that high probability behaviors can serve as effective reinforcers for low probability behaviors when made contingent on the occurrence of that low probability behavior.
Your client, Michael, engages in high rates of stereotypic behavior, primarily jumping, that is disruptive in most environments. You have had little success in finding potential reinforcers that are sufficiently motivating to serve as reinforcers. You decide to introduce another sensory activity, slime, to see if you can introduce a new reinforcer for times when a more active reinforcer would be too disruptive.
To get started, you make jumping contingent on just touching the slime with one finger since he is somewhat reluctant to touch it. You gradually build the expectation that he touch it for longer periods (seconds then minutes) while following the activity each time with jumping. Over time, Michael begins to reach for the slime when given a choice between slime and a rice bin.
For more information about the Premack Principle, read our article: 5 Ways to Use the Premack Principle You Haven’t Tried.
While these strategies take time to expand the array of potential reinforcers, they are valuable tools in your ABA toolbox.
Looking for potential reinforcers? My clients love the toys available in these 2 packs:
1993. Behavior Assessment Guide. [PDF] Los Angeles, CA: IABA, pp.81-98. Available at: http://www.aba-instituut.nl/back-site/upload/content/reinforcementinventory.pdf (Accessed 7 February 2021).
Ala’i-Rosales, S., Zeug, N. M., & Baynham, T. Y. (2008). The development of interests in children with autism: A method to establish baselines for analyses and evaluation. Behavioral Development Bulletin, 14(1), 3.
Carr, J. E., Nicolson, A. C., & Higbee, T. S. (2000). Evaluation of a brief multiple‐stimulus preference assessment in a naturalistic context. Journal of Applied Behavior Analysis, 33(3), 353-357.
Cooper, J. O., Heron, T. E., & Heward, W. L. (2007). Applied behavior analysis. Columbus: Merrill Pub.
Gottschalk, J. M., Libby, M. E., & Graff, R. B. (2000). The effects of establishing operations on preference assessment outcomes. Journal of Applied Behavior Analysis, 33(1), 85-88.
Leaf, J. B., Oppenheim‐Leaf, M. L., Leaf, R., Courtemanche, A. B., Taubman, M., McEachin, J., … & Sherman, J. A. (2012). Observational effects on the preferences of children with autism. Journal of Applied Behavior Analysis, 45(3), 473-483.
Mason, S. A., McGee, G. G., Farmer‐Dougan, V., & Risley, T. R. (1989). A practical strategy for ongoing reinforcer assessment. Journal of Applied Behavior Analysis, 22(2), 171-179.
Roane, H. S., Vollmer, T. R., Ringdahl, J. E., & Marcus, B. A. (1998). Evaluation of a brief stimulus preference assessment. Journal of Applied Behavior Analysis, 31(4), 605-620.