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State-dependent judgement bias in Drosophila: evidence for evolutionarily primitive affective processes

Research output: Contribution to journalArticle

Original languageEnglish
Article number20170779
Number of pages4
JournalBiology Letters
Early online date28 Feb 2018
DateAccepted/In press - 5 Feb 2018
DateE-pub ahead of print - 28 Feb 2018
DatePublished (current) - Feb 2018


Affective states influence decision-making under ambiguity in humans and other animals. Individuals in a negative state tend to interpret ambiguous cues more negatively than individuals in a positive state. We demonstrate that the fruit fly, Drosophila melanogaster, also exhibits state-dependent changes in cue interpretation. Drosophila were trained on a Go/Go task to approach a positive (P) odour associated with a sugar reward and actively avoid a negative (N) odour associated with shock. Trained flies were then either shaken to induce a purported negative state or left undisturbed (control), and given a choice between: air or P; air or N; air or ambiguous odour (1 : 1 blend of P : N). Shaken flies were significantly less likely to approach the ambiguous odour than control flies. This ‘judgement bias’ may be mediated by changes in neural activity that reflect evolutionarily primitive affective states. We cannot say whether such states are consciously experienced, but use of this model organism's versatile experimental tool kit may facilitate elucidation of their neural and genetic basis.

    Research areas

  • affective states, judgement bias, Drosophila, fruit flies

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    Licence: CC BY


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