Responding by exclusion in temporal discrimination tasks.
Exclusion responding shows up when people judge unfamiliar time gaps, so you can harness the effect to teach new discriminations with fewer direct trials.
01Research in Context
What this study did
College students played a computer game with two steps. First they learned to tell short beeps from long beeps. Then they saw pairs of lights and had to pick the one that matched the beep length they just heard.
Sometimes the beep was brand new, between the trained short and long times. When that happened, students usually picked the new light they had never seen before. This is called exclusion: rejecting the known choice and selecting the unknown one.
What they found
Students kept choosing the unfamiliar light after the middle-length beep. They were not taught to do this. The new duration alone pushed them to exclude the old choices.
The result shows exclusion responding can be driven only by time cues, not just pictures or words.
How this fits with other research
Felipe de Souza et al. (2014) saw the same exclusion pattern in rats that picked a new picture after rejecting a known bad one. The procedure is the same; the species and cue type changed.
Mandel et al. (2022) took exclusion further. Three children with autism learned tacts for two objects, then tacted and pointed to a third object by exclusion. The target paper proves the mechanism works with pure time, while Mandel shows it can build language in learners with autism.
Nevin (1969) first showed humans can time events in a fear-conditioning game. Cippola et al. (2014) add exclusion probes to that timeline, updating the method after 45 years.
Why it matters
You can use exclusion trials any time you teach a new skill. After a student masters short vs long wait times, slip in a middle wait and let the learner reject the old options. The same move works when you teach new tacts, matching tasks, or visual discriminations. You save teaching trials and let time itself do part of the work.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Insert one probe trial: after the learner knows 2 s vs 8 s, present a 5 s beep and let the student pick between a brand-new light and the old S- light.
02At a glance
03Original abstract
Responding by exclusion, one of the most robust phenomena in Experimental Psychology, describes a particular form of responding observed in symbolic, matching-to-sample tasks. Given two comparison stimuli, one experimentally defined and one experimentally undefined, the participant prefers the undefined comparison following an undefined sample. The goal of the present study was to determine whether responding by exclusion could be obtained using samples that varied along a single dimension. Using a double temporal bisection task, 10 university students learned to choose visual comparisons (colored circles) based on the duration of a tone. In tests of exclusion, sample stimuli with new durations were followed by comparison sets that included one previously trained, defined comparison (colored circle) and one previously untrained, undefined comparison (geometric shape). Participants preferred the defined comparisons following the defined samples and the undefined comparisons following the undefined samples, the choice pattern typical of responding by exclusion. The use of samples varying along a single dimension allows us to study the interaction between stimulus generalization gradients and exclusion in the control of conditional responding.
Journal of the experimental analysis of behavior, 2014 · doi:10.1002/jeab.71