Opposite Effects of Early-Life Competition and Developmental Telomere Attrition on Cognitive Biases in Juvenile European Starlings.
Opposite Effects of Early-Life Competition and Developmental Telomere Attrition on Cognitive Biases in Juvenile European Starlings.
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DOI：
10.1371/journal.pone.0132602
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Nettle D
中科院分区：
文献类型：
--
作者：
Bateson M;Emmerson M;Ergün G;Monaghan P;Nettle D
情绪是持久的情感状态，我们假设它应该受到个体的发展经历及其当前躯体状态的影响。我们在一项旨在提供情绪认知测量的判断偏差任务中测试了由控制巢大小引起的早期生活逆境是否会改变幼年欧洲椋鸟（Sturnus vulgaris）的决定。我们预测，来自较大群体的椋鸟，特别是那些经历过更多比自己更大的巢穴竞争者的椋鸟，会对奖励的期望降低，这表明一种“悲观”、类似抑郁的情绪。我们使用了“走/不走”任务，训练 30 只椋鸟探测与隐藏在下面的可口黄粉虫相关的灰卡圆盘，并避开与隐藏在下面的有毒奎宁注射黄粉虫相关的不同颜色的灰卡圆盘。随后测试了鸟类对受过训练的刺激以及对介于两者之间的新颖的、模糊的刺激的反应潜伏期。在巢中经历过更大竞争的鸟类能够更快地探测经过训练的刺激，因此有必要在后续分析鸟类对模糊刺激的反应时对这种差异进行统计控制。正如预测的那样，拥有更多、更大巢穴竞争者的鸟类在探索模糊刺激方面表现出相对较长的潜伏期，这表明对奖励的期望降低，并产生“悲观”、抑郁样的情绪。然而，发育端粒磨损程度较高的鸟类（一种与发病率增加和预期寿命缩短相关的细胞衰老指标，我们认为可以将其用作躯体状态的指标）在探测模糊刺激时表现出更短的潜伏期。这通常被解释为更积极或“乐观”的情感状态的证据。因此，巢中竞争的加剧和当前较差的躯体状态似乎对认知偏差产生相反的影响。我们的结果让我们质疑，当受到模糊刺激时，奖励期望的增加是否总是表明更积极的情感状态。我们讨论了当前躯体状态较差的鸟类可能采取“饥饿”认知表型的可能性，这种表型可能会驱动在食物奖励认知偏差任务中通常被解释为“乐观”的行为。
Moods are enduring affective states that we hypothesise should be affected by an individual’s developmental experience and its current somatic state. We tested whether early-life adversity, induced by manipulating brood size, subsequently altered juvenile European starlings’ (Sturnus vulgaris) decisions in a judgment bias task designed to provide a cognitive measure of mood. We predicted that starlings from larger broods, specifically those that had experienced more nest competitors larger than themselves would exhibit reduced expectation of reward, indicative of a ‘pessimistic’, depression-like mood. We used a go/no-go task, in which 30 starlings were trained to probe a grey card disc associated with a palatable mealworm hidden underneath and avoid a different shade of grey card disc associated with a noxious quinine-injected mealworm hidden underneath. Birds’ response latencies to the trained stimuli and also to novel, ambiguous stimuli intermediate between these were subsequently tested. Birds that had experienced greater competition in the nest were faster to probe trained stimuli, and it was therefore necessary to control statistically for this difference in subsequent analyses of the birds’ responses to the ambiguous stimuli. As predicted, birds with more, larger nest competitors showed relatively longer latencies to probe ambiguous stimuli, suggesting reduced expectation of reward and a ‘pessimistic’, depression-like mood. However, birds with greater developmental telomere attrition—a measure of cellular aging associated with increased morbidity and reduced life-expectancy that we argue could be used as a measure of somatic state—showed shorter latencies to probe ambiguous stimuli. This would usually be interpreted as evidence for a more positive or ‘optimistic’ affective state. Thus, increased competition in the nest and poor current somatic state appear to have opposite effects on cognitive biases. Our results lead us to question whether increased expectation of reward when presented with ambiguous stimuli always indicates a more positive affective state. We discuss the possibility that birds in poor current somatic state may adopt a ’hungry’ cognitive phenotype that could drive behaviour commonly interpreted as ‘optimism’ in food-rewarded cognitive bias tasks.