Mirror self-recognition (MSR), usually considered a marker of self-awareness, occurs in several species and may reflect a capacity that has evolved in small incremental steps. In line with research on human development and building on previous research adopting a gradualist framework, we categorized the initial mirror responses of naïve spider monkeys (Ateles geoffroyi) according to four levels. We compared social, exploratory, contingent and self-exploratory responses to a mirror and faux mirror during three short trials. If spider monkeys respond as most monkey species, we predicted they would perform at level 0, mainly showing social behavior toward their mirror-image. However, because spider monkeys show enhancement of certain cognitive skills comparable to those of great ape species, we predicted that they would perform at level 1a (showing exploratory behavior) or 1b (showing contingent behavior). GLMMs revealed that monkeys looked behind and visually inspected the mirror significantly more in the mirror than the faux mirror condition. Although the monkeys engaged in contingent body movements at the mirror, this trend was not significant. Strikingly, they showed no social behaviors toward their mirror-image. We also measured self-scratching as an indicator of anxiety and found no differences in frequencies of self-scratching between conditions. Therefore, in contrast to most findings on other species, spider monkeys did not treat their image as another monkey during their initial exposure to the mirror. In fact, they reached at least level 1a within minutes of mirror exposure. These responses recommend spider monkeys as good candidates for further explorations into monkey self-recognition. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

中文翻译：

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镜子中没有其他猴子可食蜘蛛猴（Ateles geoffroyi）。

镜像自我识别（MSR）通常被认为是自我意识的标记，它发生在多个物种中，并且可能反映出以较小的增量步长演变的能力。与人类发展研究相一致，并在先前研究采用渐进主义框架的基础上，我们将幼稚蜘蛛猴（Ateles geoffroyi）的初始镜像反应分为四个级别。在三个简短的试验中，我们比较了社会，探索性，偶然性和自我探索对镜子和人造镜子的反应。如果蜘蛛猴能像大多数猴子一样做出反应，我们预测它们的表现将为0级，主要表现出对其镜像的社交行为。但是，由于蜘蛛猴显示出与大猿猴相当的某些认知能力，我们预测他们的表现将达到1a级（显示探索行为）或1b级（显示或有行为）。GLMMs发现猴子向后看，并且在视觉上检查镜子比在人造镜子条件下要多得多。尽管猴子在镜子处进行偶然的身体运动，但这种趋势并不明显。令人惊讶的是，他们没有表现出对自己镜像的社交行为。我们还测量了自我抓取作为焦虑的指标，并且发现条件之间的自我抓取频率没有差异。因此，与其他物种的大多数发现相反，蜘蛛猴在最初暴露于镜子期间并未将其图像当作另一只猴子。实际上，它们在镜子曝光后的几分钟内至少达到了1a级。这些回应建议蜘蛛猴是进一步探索猴子自我认知的良好候选者。（PsycInfo数据库记录（c）2020 APA，保留所有权利）。