Physically stressed bees expect less reward in an active choice judgement bias test

• DOI: 10.1101/2023.10.06.561175
• Publication Date: 2023-10-09T13:30:13Z
• Authors: Olga Procenko; Jenny Read; Vivek Nityananda
• Keywords: Judgement

Abstract Emotion-like states in animals are commonly assessed using judgment bias tests, which measure responses to ambiguous information. A few studies have recently used these tests argue for the presence of emotion-like insects. However, results from most could other explanations, including changes motivation and attention. To control we therefore developed a novel test, requiring bumblebees make an active choice indicating their interpretation stimuli. Bumblebees were trained associate high or low rewards, delivered two different reward chambers, with distinct colors. Two groups bees then physically stressed by shaking trapping, while third group served as control. We subsequently presented colors between learnt noted chamber they chose. When colors, less likely than enter previously associated reward. modelled bee behavior signal detection drift diffusion models showed that were, respectively, more respond optimistically pessimistically cues. The model further was explained reduction prior expectation rewards. Our findings thus provide strong evidence suggest stress-induced pessimistic is reduced higher