An Initial Test of Reconsolidation in Disgust-Related Learning and Extinction

This study examines whether the spacing of a single unreinforced retrieval trial relative to extinction learning allows for “rewriting” the original disgust association, thereby preventing the return of disgust using a paradigm that employs disgust-relevant unconditioned stimuli (US). During conditioning, disgusting US were paired with a color square that served as the conditioned stimuli (CS). Participants (n = 54) then returned to the lab 24 hours later and received a “reactivation” intervention which consisted of one unpaired presentation of the CS+. Participants were then randomized to receive extinction trials either 10 min (Group A) or 6 hours (Group B) after reactivation. A third control group (Group C) did not receive the reactivation manipulation before extinction. Participants returned 24 hours later for additional extinction trials and at a 1-month follow-up for disgust reinstatement. Although the paradigm resulted in participants evaluating the CS+ as significantly more unpleasant after being associated with a disgust-relevant US, extinction learning within the reconsolidation window did not influence self-reported reduction or return of disgust. However, there was some evidence suggesting that those who received reactivation (Groups A and B), regardless of timing, evaluated the CS+ as less unpleasant after extinction relative to acquisition, whereas this pattern was not observed among those who did not receive reactivation (Group C). The implications of these findings for anxiety-related disorders in which disgust has been implicated will be discussed.

Sensory preconditioning in honeybees

Sensory preconditioning means that reinforcement of stimulus A after unreinforced exposure to a compound AB also leads to responses to stimulus B. Here, we describe and analyze sensory preconditioning in an insect, the honeybee Apis mellifera. Using two-element odorant compounds in classical conditioning of the proboscis extension reflex, we found (i) that sensory preconditioning is not due to stimulus generalization, (ii) that paired, but not unpaired, presentation of elements supports sensory preconditioning, (iii) that simultaneous, but not sequential, exposure to the elements of the compound supports sensory preconditioning and (iv) that a single presentation of the compound yields maximal sensory preconditioning. The results are discussed with respect to configural and chain-like associative explanations for sensory preconditioning. We suggest an experience-dependent step of compound processing, establishing configural units, as an additional explanation for sensory preconditioning.