In Applied Behavior Analysis (ABA), preference assessments play a crucial role in identifying potential reinforcers that can be used to motivate individuals and increase the likelihood of desired behaviors. These assessments help therapists determine which stimuli a client finds most reinforcing, ensuring that interventions are both effective and individualized.
Preference assessments are not a one-time process. They should be conducted periodically throughout therapy to account for changes in client preferences. Various types of preference assessments exist, each with unique advantages depending on the individual’s needs, abilities, and communication skills.
Types of Preference Assessments
1. Natural Free Operant Preference Assessment
A natural free operant preference assessment involves observing the client in their natural environment without intervention. The therapist allows the client to engage freely with available items or activities and records the frequency and duration of interactions.
Advantages:
- Captures genuine, real-world preferences.
- Non-intrusive and allows for spontaneous choices.
- Useful for individuals with strong communication skills.
Example:
A therapist observes a child in a classroom setting and notes that they frequently choose to play with blocks over other available activities. Blocks may then be used as a potential reinforcer in therapy.
2. Contrived Free Operant Preference Assessment
A contrived free operant preference assessment is similar to the natural free operant assessment but takes place in a structured setting. The therapist introduces a variety of items or activities and observes how the client interacts with them.
Advantages:
- Allows exposure to new items that the client may not have encountered before.
- Ideal for individuals with limited experience with certain stimuli.
Example:
A therapist places several toys in front of a child and allows them to explore. The therapist records which items the child engages with the longest, helping identify preferred reinforcers.
3. Single Item Preference Assessment
In a single item preference assessment, one item is presented at a time, and the therapist records the client’s response. Responses may include interaction with the item, avoidance, or no response.
Advantages:
- Useful for individuals with limited choice-making abilities.
- Helps assess whether an item is truly reinforcing.
Example:
A therapist presents a small snack to a child. If the child reaches for it and eats it immediately, it may be a strong reinforcer. If they ignore it, the therapist may try a different item.
4. Paired Choice Preference Assessment (Forced Choice Assessment)
A paired choice preference assessment involves presenting two items at a time and recording which item the client selects. The process is repeated multiple times with different pairings to determine a ranked preference hierarchy.
Advantages:
- More structured than free operant assessments.
- Helps determine relative preference between items.
- Effective for individuals who engage with most items in a single-item assessment.
Example:
A therapist presents a child with a ball and a puzzle. The child selects the puzzle. In future trials, the puzzle is paired with other items to determine if it remains a high-preference choice.
5. Multiple Stimulus Without Replacement (MSWO) Preference Assessment
In a Multiple Stimulus Without Replacement (MSWO) assessment, the therapist presents multiple items at once and allows the client to select one. Once selected, that item is removed, and the process continues until all items have been chosen.
Advantages:
- Produces a clear preference ranking.
- Efficient for identifying the most reinforcing items quickly.
Example:
A therapist presents five toys. The child chooses a toy car first, a stuffed animal second, and a coloring book third. This indicates a preference ranking among the items.
6. Multiple Stimulus With Replacement (MSW) Preference Assessment
A Multiple Stimulus With Replacement (MSW) assessment is similar to MSWO, but the selected item is placed back into the array for the next trial.
Advantages:
- Useful for assessing repeated selections.
- Reduces the impact of novelty influencing preference.
Example:
A child repeatedly selects a fidget spinner when given multiple toy options. This suggests that the fidget spinner is a strong reinforcer.
Why Preference Assessments Matter
Preference assessments are an essential part of ABA therapy because they allow therapists to:
✔️ Use individualized reinforcers to motivate clients.
✔️ Avoid using non-preferred items, which could reduce engagement.
✔️ Improve intervention effectiveness by reinforcing positive behaviors with highly preferred stimuli.
✔️ Adjust therapy strategies as client preferences change over time.
Conducting the right preference assessment depends on the individual’s abilities and communication level. Whether observing natural interactions or using structured choice trials, preference assessments help ensure that reinforcers are truly effective in supporting behavior change.
By integrating these assessments into therapy, practitioners can develop reinforcement strategies that maximize success and create meaningful progress for their clients.