The study of consistent individual differences in behaviour has become an important focus in research on animal behaviour. Behavioural phenotypes are typically measured through standardized testing paradigms and one frequently used paradigm is the novel object test. In novel-object tests, animals are exposed to new (unknown) objects and their reaction is quantified. When repeating trials to assess the temporal consistency of individual differences, researchers face the dilemma of whether to use the same or different novel objects, since the same stimulus can result in habituation, while exposure to different objects can result in context-dependent responses. We performed a quantitative assessment of 254 effect sizes from 113 studies on novel-object trials to evaluate the properties of this testing paradigm, in particular the effect of object novelty and time interval between novel-object trials on estimates of individual consistency. We found an increase of sample sizes and an increase of estimates of repeatabilities with time. The vast majority of short-term studies (<one month) used different novel objects, while long-term studies (>one month) used either the same or different novel objects about equally often. The average estimate for individual consistency was r = 0.47 (short-term r = 0.52, long-term r = 0.44). Novelty, time interval between trials and their interaction together explained only 3% of the total heterogeneity. Overall, novel-object trials reliably estimate individual differences in behaviour, but results were very heterogeneous even within the same study species, suggesting susceptibility to unknown details in testing conditions. Most studies that measure novel-object responses in association with food label the trait as neophobia, while novel-object trials in a neutral context are labelled variously as boldness/shyness, exploratory behaviour or neophobia/neophilia. Neophobia/neophilia is also the term most specific to novel object presentations. To avoid ambiguity, we suggest object neophobia/neophilia as the most specific label for novel-object responses.

中文翻译：

---

第一眼的新颖性：基于元分析的新颖对象范式的批判性评估。

一致的个体行为差异的研究已成为动物行为研究的重要重点。行为表型通常通过标准化的测试范式进行测量，一种经常使用的范式是新颖的对象测试。在新物体测试中，动物要接触新的（未知）物体，并对其反应进行定量。在重复试验以评估个体差异的时间一致性时，研究人员面临着使用相同还是不同新颖对象的难题，因为相同的刺激会导致习惯，而暴露于不同的对象则会导致上下文相关的响应。我们从113项针对新对象试验的研究中进行了254种效果大小的定量评估，以评估该测试范例的特性，特别是对象新颖性和新颖对象试验之间的时间间隔对个人一致性估计的影响。我们发现样本量随着时间的增长而增加，并且可重复性的估计值也随着增加。绝大多数短期研究（<一个月）使用不同的新颖对象，而长期研究（>一个月）使用相同或不同的新颖对象几乎相同。个体一致性的平均估计为r = 0.47（短期r = 0.52，长期r = 0.44）。新颖性，试验之间的时间间隔以及它们之间的相互作用一起只能解释全部异质性的3％。总体而言，新对象试验可以可靠地估算出行为的个体差异，但即使在相同的研究物种中，结果也非常不相同，表明对测试条件中未知细节的敏感性。大多数与食物相关的测量新对象反应的研究将其特征标记为新恐惧症，而在中性背景下的新对象试验则被不同程度地标记为大胆/害羞，探索性行为或新恐惧症/亲友病。恐惧症/新人症也是最新颖的事物表现形式。为避免含糊不清，我们建议对象新恐惧症/亲友性是新颖对象响应的最具体标签。