Differential aversive learning enhances orientation discrimination

ABSTRACT

A number of recent studies have documented rapid changes in behavioural sensory acuity induced by aversive learning in the olfactory and auditory modalities. The effect of aversive learning on the discrimination of low-level features in the visual system of humans remains unclear. Here, we used a psychophysical staircase procedure to estimate discrimination thresholds for oriented grating stimuli, before and after differential aversive learning. We discovered that when a target grating orientation was conditioned with an aversive loud noise, it subsequently led to an improvement of discrimination acuity in nearly all subjects. However, no such change was observed in a control group conditioned to an orientation shifted by ±90° from the target. Our findings cannot be explained by contextual learning or sensitisation factors. The results converge with those reported in the olfactory modality and provide further evidence that early sensory systems can be rapidly modified by recently experienced reinforcement histories.

KEYWORDS:

• Conditioning
• aversive learning
• orientation discrimination
• just noticeable difference
• visual system

Acknowledgements

Appreciation is expressed to Dr Brandon Gibb for his help with the mental health screening portion of the study. The authors would also like to thank Chris Caracciolo, Molly O’Hagan, Ryan O’Rourke, and Kendra Deschamps for their assistance with data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. We opted for a between-subjects design in an effort to minimise participant fatigue and potential practice effects that would accrue from doubling the number of experimental trials.

2. This is consistent with evidence from non-human animal studies that non-learners evidence worse discrimination acuity while learners evidence increased discrimination acuity in an aversive conditioning preparation (Aizenberg & Geffen, 2013).

Additional information

Funding

This research was supported by a research grant from the National Institute of Mental Health (NIMH) [grant number 1R03MH105716] to V. Miskovic.