Humans find members of the opposite sex more attractive when their image is spatially associated with the color red. This effect even occurs when the red color is not on the skin or clothing (i.e. is extraneous). We hypothesize that this extraneous color effect could be at least partially explained by a low-level and biologically innate generalization process, and so similar extraneous color effects should be observed in non-humans. To test this possibility, we examined the influence of extraneous color in rhesus macaques (Macaca mulatta). Across two experiments, we determined the influence of extraneous red on viewing preferences (assessed by looking time) in free-ranging rhesus monkeys. We presented male and female monkeys with black and white photographs of the hindquarters of same and opposite sex conspecifics on either a red (experimental condition) or blue (control condition) background. As a secondary control, we also presented neutral stimuli (photographs of seashells) on red and blue backgrounds. We found that female monkeys looked longer at a picture of a male scrotum, but not a seashell, on a red background (Experiment 1), while males showed no bias. Neither male nor female monkeys showed an effect of color on looking time for female hindquarters or seashells (Experiment 2). The finding for females viewing males suggests that extraneous color affects preferences among rhesus macaques. Further, it raises the possibility that evolutionary processes gave rise to extraneous color effects during human evolution.
|Original language||English (US)|
|Number of pages||7|
|Journal||Evolution and Human Behavior|
|State||Published - Jan 1 2015|
Bibliographical noteFunding Information:
This work was supported by the Sloan Foundation , by NIDA , and by two Reach fellowships provided by the University of Rochester to undergraduate assistants. The population of Cayo Santiago is currently supported by the National Center for Research Resources (NCRR grant number: 8 P40 OD012217 ) and the Office of Research Infrastructure Programs (ORIP) of the National Institute of Health and the Medical Science Campus of the University of Puerto Rico . The content of the publication is solely the responsibility of the authors and does not necessarily represent the official views of NCRR or ORIP.
© 2015 Elsevier Inc.
- Body colors
- Rhesus macaques
- Sexual signals