Formation of equivalence classes with the presentation of stimuli for fractions of a second

Studies have shown that it is possible to establish conditional relations among stimuli presented for very brief durations in a matching-to-sample task. Objectives: In the present investigation, we asked whether it is possible to establish equivalence relations following the training of conditional relations among stimuli presented for fractions of a second. Methods: Two experiments were conducted. Adults performed a successive Go/No-go discrimination task in which one element of a compound stimuli was presented for durations as short as 33 ms. Stimuli were combinations of geometric figures and colored backgrounds. In the conditional discrimination training, touching only the correct stimuli was followed by reinforcement. Emergent stimulus relations were tested under extinction. Results: Presenting either figures or colors with durations as short as 33 ms promoted the acquisition of baseline conditional relations that generated the emergence of corresponding equivalence classes. Conclusions: Stimuli, with durations as short as 33 ms, exerted discriminative control over human participants and had the capability to establish equivalence classes, which holds significant importance for symbolic learning.