Are monkeys intuitive Aristotelians? Associations between target size and vertical target position in long-tailed macaques

Abstract

Different hypotheses have been put forward to explain the interaction between size perception and spatial position. To explore the evolutionary roots of these phenomena, we tested long-tailed macaques' performance in a two-choice discrimination task on a touchscreen and contrasted two hypotheses. First, a hierarchy association in which large objects are associated with top positions, due to a link between power, dominance and importance with top position. Second, a naive Aristotelian association in which large objects are associated with bottom positions, due to the experience that larger objects are heavier and thus more likely to be found at the bottom. Irrespective of training regime (positively reinforcing the small (Touch-Small) or large (Touch-Large) stimulus), the monkeys had a bias to touch the bottom compared to the top location. Individuals in the Touch-Small group took significantly longer to acquire the task, but subsequently made fewer mistakes. When presented with two stimuli of equal medium size, the Touch-Large group had a clear bias to touch the lower stimulus, while the Touch-Small group touched both locations at equal rates. Our findings point to an innate bias towards larger stimuli and a natural preference for the lower position, while the extent of interaction between size and position depends on executive control requirements of a task.

The Roles of Group Status and Group Membership in the Practice of Hypodescent

“…Future research should also consider other manipulations of social status. That is, in the present research, we manipulated two powerful indicators of social status: a group’s wealth (i.e., the quantity and quality of their resources) and vertical position (i.e., whether they were positioned over or under another group), both of which have been shown in prior research to signal status or power (Horwitz et al, ; Keupp, Barbarroja, Topolinski, & Fischer, ; Lakoff & Johnson, ; Lu, Schubert, & Zhu, ; Olson et al, ). There are, however, additional cues to social power that may elicit stronger effects, including, for example, a group’s ability to control the resources of others, to achieve their goals at the expense of others, or to grant or deny others permission (Gülgöz & Gelman, ).…”