A Screen-Peck Task for Investigating Cognitive Bias in Laying Hens.
A Screen-Peck Task for Investigating Cognitive Bias in Laying Hens.
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DOI：
10.1371/journal.pone.0158222
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Mendl M
中科院分区：
文献类型：
--
作者：
Deakin A;Browne WJ;Hodge JJ;Paul ES;Mendl M
情感诱发的认知判断偏差在人类和动物中都存在。处于消极情感状态的动物比处于积极情感状态的动物更倾向于消极地解读模棱两可的线索，反之亦然。因此，研究动物对模糊线索的反应可以作为情感状态的替代衡量标准。我们使用一种新的认知偏差任务来研究蛋鸡对模糊刺激的反应。在“啄屏幕”任务中，母鸡被训练去啄电脑屏幕上呈现的饱和度高/低的橙色圆圈（正提示p）以获得粉虫奖励，而当呈现相反饱和度的橙色圆圈（负提示n）时不啄，以避免一秒钟的吹气。模糊提示是介于P和N提示（接近正的np；中间的m；接近负的nn）之间的橙色圆圈，并且没有奖励。线索啄食显示了一条从P到NP、M、NN到N的清晰的概括曲线，这表明母鸡能够将颜色饱和度与奖励或惩罚联系起来，并且能够区分与所学线索或多或少相似的刺激。在六次测试中，没有证据表明对模糊线索的啄食反应会消失。在重复测量交叉设计中，我们通过在测试期间改变温度至~20°C或~29°C来操纵情感状态。母鸡已经被证明更喜欢较高范围的温度，因此我们假设暴露在较高的温度下会引起相对积极的情感状态。在温暖条件下测试的母鸡比在凉爽条件下测试的母鸡更有可能啄出M探针，这表明在这里测试的范围内增加的温度可能对母鸡有一些积极的影响，引起积极的认知偏差。
Affect-induced cognitive judgement biases occur in both humans and animals. Animals in a more negative affective state tend to interpret ambiguous cues more negatively than animals in a more positive state and vice versa. Investigating animals’ responses to ambiguous cues can therefore be used as a proxy measure of affective state. We investigated laying hens’ responses to ambiguous stimuli using a novel cognitive bias task. In the ‘screen-peck’ task, hens were trained to peck a high/low saturation orange circle presented on a computer screen (positive cue–P) to obtain a mealworm reward, and to not peck when the oppositely saturated orange circle was presented (negative cue–N) to avoid a one second air puff. Ambiguous cues were orange circles of intermediate saturation between the P and N cue (near-positive–NP; middle–M; near-negative–NN), and were unrewarded. Cue pecking showed a clear generalisation curve from P through NP, M, NN to N suggesting that hens were able to associate colour saturation with reward or punishment, and could discriminate between stimuli that were more or less similar to learnt cues. Across six test sessions, there was no evidence for extinction of pecking responses to ambiguous cues. We manipulated affective state by changing temperature during testing to either ~20°C or ~29°C in a repeated measures cross-over design. Hens have been shown to prefer temperatures in the higher range and hence we assumed that exposure to the higher temperature would induce a relatively positive affective state. Hens tested under warmer conditions were significantly more likely to peck the M probe than those tested at cooler temperatures suggesting that increased temperature in the ranges tested here may have some positive effect on hens, inducing a positive cognitive bias.