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Published on: August 1, 2018
Rapid detection of snakes by Japanese monkeys (Macaca fuscata): an evolutionarily predisposed visual system
Masahiro Shibasaki1, Nobuyuki Kawai
1Cognitive Informatic Unit, Graduate School of Information Science, Nagoya University, Japan.
Summary
Laboratory-reared macaque monkeys show faster visual detection of snakes than flowers, similar to humans. This suggests an innate sensitivity to evolutionarily relevant threat stimuli in primates.
Area of Science:
- Evolutionary psychology
- Primate behavior
- Visual cognition
Background:
- Humans exhibit heightened sensitivity to biologically threatening stimuli like snakes.
- Faster visual search responses to snakes compared to neutral stimuli (e.g., flowers) are well-documented in humans.
Purpose of the Study:
- To investigate whether nonhuman primates share this enhanced visual detection of evolutionarily relevant threat stimuli.
- To determine if laboratory-reared macaques, lacking direct snake experience, show similar responses to humans.
Main Methods:
- Macaque monkeys (Macaca fuscata) were presented with visual search tasks involving pictures of snakes and flowers.
- Experiments included both color and grayscale images to assess stimulus properties.
- Response times to identify snakes among flowers versus flowers among snakes were recorded.
Main Results:
- Macaque monkeys responded significantly faster when searching for snake images compared to flower images.
- This enhanced detection of snakes was observed regardless of whether the images were in color or grayscale.
- The findings were consistent across different experimental conditions.
Conclusions:
- This study provides the first evidence of enhanced visual detection of evolutionarily relevant threat stimuli in nonhuman primates.
- The results suggest that sensitivity to such stimuli may be an evolutionarily conserved trait in primates.
- This may have implications for understanding the evolutionary basis of fear and threat perception.
