Second-Order Relational Manipulations Affect Both Humans and Monkeys
2011

How Humans and Monkeys Process Faces

Sample size: 25 publication 10 minutes Evidence: moderate

Author Information

Author(s): Dahl Christoph D., Logothetis Nikos K., Bülthoff Heinrich H., Wallraven Christian

Primary Institution: Max Planck Institute for Biological Cybernetics

Hypothesis

Macaques and humans will show different sensitivities to configurally altered faces based on their species expertise.

Conclusion

Both macaques and humans show sensitivity to second-order relational properties in faces, but this sensitivity is stronger for conspecific faces and when the faces are upright.

Supporting Evidence

  • Both species showed greater interest in upright faces compared to inverted faces.
  • Macaques demonstrated sensitivity to configural changes in conspecific faces.
  • Humans showed a significant rebound of interest for manipulated upright faces.
  • Eye tracking revealed differences in fixation patterns between species.
  • Participants were compensated for their time, ensuring ethical standards.
  • Face stimuli were carefully manipulated to assess perceptual expertise.

Takeaway

Monkeys and humans can tell faces apart, especially when they are looking at faces of their own kind and when the faces are right-side up.

Methodology

The study used a habituation-dishabituation paradigm with eye tracking to compare how macaques and humans respond to altered faces.

Potential Biases

Potential biases may arise from the limited sample size and the specific conditions under which the experiments were conducted.

Limitations

The study's findings may not generalize to other species or face processing tasks outside the experimental conditions.

Participant Demographics

22 human participants (12 females, ages 18-35) and 3 rhesus macaques (ages 5-7 years).

Statistical Information

P-Value

p<0.001

Statistical Significance

p<0.001

Digital Object Identifier (DOI)

10.1371/journal.pone.0025793

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