Can brown lemurs (Eulemur fulvus) learn to deceive a human competitor?

Area of Science:

• Primate cognition
• Animal behavior
• Comparative psychology

Background:

• Understanding deception in non-human animals is crucial for cognitive evolution research.
• Previous studies explored deception in primates using similar paradigms.
• Lemurs, as prosimian primates, offer a unique perspective on the evolution of complex behaviors.

Purpose of the Study:

• To investigate whether brown lemurs (Eulemur fulvus) can learn to deceive a human trainer.
• To assess if lemurs can differentiate between cooperative and competitive social contexts.
• To explore the role of associative learning in deceptive communication.

Main Methods:

• Four brown lemurs participated in a task involving indicating the location of a hidden reward.
• Subjects communicated with a cooperative trainer (reward shared) and a competitive trainer (trainer kept reward).
• Two experimental setups were used: separate sessions for each trainer and randomized trials within sessions.

Main Results:

• Lemurs did not initially show distinct strategies when trainers were in separate sessions.
• In a randomized trial design, one lemur significantly chose the baited location for the cooperative trainer.
• This lemur also reliably chose the unbaited location when interacting with the competitive trainer, indicating deception.

Conclusions:

• Brown lemurs can learn to manipulate information to deceive a competitive trainer.
• The ability to deceive appears context-dependent, emerging when trainers were randomized.
• Associative learning likely underlies the observed deceptive pointing behavior in lemurs, similar to other primates.