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

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 utilisation of this model organism’s versatile experimental tool kit may facilitate elucidation of their neural and genetic basis.

情感状态会影响人类及其他动物在模糊情境下的决策行为。处于负面情感状态的个体，相较于正面状态个体，更倾向于对模糊线索做出消极解读。本研究证实，黑腹果蝇（Drosophila melanogaster）同样存在线索解读受状态调控的现象。研究人员采用双趋任务（Go/Go task）训练果蝇：让其趋近与蔗糖奖赏绑定的正性（P）气味，并主动躲避与电击绑定的负性（N）气味。随后将训练完成的果蝇分为两组：一组通过摇晃诱导出据称的负面状态，另一组保持安静作为对照组；随后让它们分别在以下三组配对中做出选择：空气与P气味、空气与N气味、空气与模糊气味（P:N按1:1混合的混合物）。相较于对照组果蝇，摇晃处理组果蝇趋近模糊气味的概率显著更低。这种“判断偏差”或许由反映进化保守性原始情感状态的神经活动变化所介导。我们尚无法确定此类状态是否存在主观意识体验，但借助这一模式生物丰富的实验工具库，或可推动其神经与遗传基础的解析。