Short report: A judgment bias task reveals stress produces a negative affective state in cuttlefish.

Abstract

Judgment Bias Tasks (JBT) are used to assess emotional state and welfare of animals in zoos, farms, and laboratories, based on a subjects interpretation of an ambiguous or intermediate cue. Animals in positive affective states are more likely to interpret the ambiguous cue positively, reflecting optimistic bias and animals with negative affect are more likely to interpret ambiguous cues pessimistically. Here, we developed a JBT assay for the stumpy-spined cuttlefish, Sepia bandensis, to determine whether cuttlefish exhibit negative affective states resulting from chronic and acute stress. Cuttlefish learned to associate food with a visual cue. Positive and neutral cues were presented twice daily until animals oriented to the positive cue and searched for food. After training, one treatment group was exposed to combined chronic and acute stress produced by 5 days of impoverished housing and once-daily simulated net capture. Our control group received no stress experience. In test trials performed after the stress experience, stressed animals had higher latencies to approach ambiguous cues, spent significantly less time in rooms with ambiguous cues once they entered, and were less likely to enter first into the ambiguous cue-paired room compared with controls. These behaviors suggest that stress induces pessimistic judgment bias in cuttlefish, the first indication of this capacity in cephalopods.