What is reflexivity in stimulus equivalence? Reflexivity is the untrained selection of a stimulus as matching itself, often written A=A. In a matching-to-sample test, a person selects the comparison identical to a sample even though that exact identity relation was never taught within the relevant preparation. Evidence depends on the learning history, novel stimuli, balanced arrays, probe conditions, independent responses, adequate opportunities, and control of position or feature cues.
A=A is compact notation
If the sample is A, the reflexivity test asks whether the person selects A from an array containing A and other comparisons. The same form applies to B=B and C=C.
The notation describes a relation. It does not describe the sensory modality, number of comparisons, response form, or training history.
The identity relation must be untrained
Directly teaching A-to-A and then testing A-to-A shows retention of a trained identity match. A reflexivity claim requires the relevant identity performance to emerge without direct teaching of that exact relation.
Researchers often use novel stimuli or carefully documented histories. Everyday materials can already have extensive identity-matching histories, making the stronger inference difficult.
Identity matching is a broader performance label
Identity matching describes selection of a physically identical comparison. It can be directly taught, maintained, generalized, or probed as an emergent relation.
A study of identity matching with preverbal children used progressive training. Its identity-matching outcome should not automatically be relabeled reflexivity because the teaching history matters.
Reflexivity joins symmetry and transitivity
Stimulus equivalence is commonly evaluated through reflexivity, symmetry, and transitivity, with combined tests sometimes used. A review of derived stimulus relations describes equivalence performances emerging from smaller trained networks.
Passing one property does not establish the others. Report the trained baseline and every tested relation separately.
Establish procedural prerequisites
Before an unreinforced probe, confirm that the person can access the stimuli, scan the array, make the response, tolerate the trial, and complete the general matching procedure.
Use instruction and practice stimuli that do not teach the test relation. If the task wording itself reveals “choose the same,” note that the verbal rule may contribute to performance.
A fictional probe example
Imani learns the matching procedure with a familiar practice set. The test then uses five novel abstract shapes that never appeared in training. Each sample appears twice with three comparisons, and positions are balanced.
Imani selects the identical comparison on 8 of 10 unreinforced trials. Errors occur on two different samples and positions. Report 8 of 10 plus sample-level results, trial order, prior exposure, and any repeated probes.
This small result supports reflexive performance in that task. It does not establish a universal equivalence repertoire or explain the process that produced it.
Prevent position and feature control
Balance comparison positions and avoid predictable sequences. Make distractors comparable in size, brightness, wear, and familiarity.
An exact copy with a unique border can be selected by border identity. That may still be physical identity, though it may miss the intended dimension. State which features define sameness for the assessment question.
Probe without teaching during the probe
Feedback or reinforcement contingent on correctness can teach the tested relation. When the purpose is to assess emergence, use a planned probe arrangement and keep consequences neutral or nondifferential as appropriate.
Record every feedback error. After teaching begins, label later performance as post-teaching rather than initial emergence.
Accessibility supports belong in the method
Provide lighting, contrast, positioning, tactile access, auditory presentation, motor supports, or a reliable selection response as needed. Preserve augmentative and alternative communication.
Adaptations should leave the identity relation intact and be reported. An inaccessible display measures the display-person mismatch alongside any target skill.
The BACB outline supplies broad context
The BACB Test Content Outline covers stimulus control, discrimination, conditional-discrimination procedures, and emergent relations. It is examination content rather than a prescribed assessment.
A qualified professional should choose and interpret probes within scope, evidence, client priorities, and context.
An interpretation checklist
- Which exact identity relations were never trained?
- Were test stimuli novel or previously familiar?
- Was the general task understood?
- Were comparison positions balanced?
- Did feedback teach any test relation?
- How many opportunities occurred per sample?
- Were access supports stable?
- Which conclusion fits the tested relations only?
Build a stimulus-history table
For each test item, record where it came from, prior exposures, whether identity matching was ever reinforced, and which practice or baseline trials included it. Add the first probe result, later probes, and any feedback. This table often reveals that one “novel” item appeared in familiar instruction or that repeated testing became teaching. Keep those items in the report and narrow the reflexivity claim to the uncontaminated set.
Archive the original trial order and materials with the table for independent review.
Related terms
Sources
Take the next step with clarity
Whether you are finding care, growing as a clinician, or building a stronger ABA practice, Finni brings the people, tools, and support together to help you move forward.
Explore clinical roles at Finni practices