May the force be with you: exploring force discrimination in chimpanzees using the force-feedback device

Area of Science:

• Comparative cognition
• Primate behavior
• Haptic perception

Background:

• Force-feedback devices are common in virtual reality but rarely used for comparative cognitive studies in animals.
• Cross-modal perception (vision-touch) is studied in primates, but active haptic perception remains unexplored.

Purpose of the Study:

• To investigate force discrimination learning in chimpanzees using a novel force-feedback device.
• To explore active haptic perception capabilities in nonhuman primates.

Main Methods:

• Chimpanzees manipulated a trackball device with varying force feedback (8.0 vs. 0.5 N) to move a cursor.
• Task involved selecting stimuli based on force cues within a trial-block procedure with decreasing block sizes.
• Performance was analyzed to understand learning strategies and the impact of force stimulus switching.

Main Results:

• No chimpanzees reached the learning criterion for force discrimination.
• Chimpanzee choice behavior was influenced by force stimulus switching, not a simple win-stay/lose-shift strategy.
• Performance was better when switching from low to high force stimuli compared to high to low.

Conclusions:

• Chimpanzees did not acquire force discrimination in this study.
• Findings suggest that force stimulus changes impact chimpanzee choice behavior, indicating some level of haptic sensitivity.
• Future research with force-feedback devices could advance understanding of primate haptic cognition.