Lateralized motor control in spider monkeys (Ateles geoffroyi): Evidence from visual-spatial working memory tasks

Area of Science:

• Primate behavior
• Neuroscience
• Comparative psychology

Background:

• Primate lateralization is crucial for understanding human brain evolution.
• Hemispheric specialization in executive functions is observed in some primate species.
• Working memory laterality in New World monkeys remains understudied.

Purpose of the Study:

• To investigate hand and tail use lateralization in spider monkeys (Ateles geoffroyi).
• To explore hemispheric specialization for working memory in this New World monkey species.

Main Methods:

• Two visual-spatial delayed match-to-sample (DMTS) tasks were administered to eight juvenile male spider monkeys.
• Tasks involved delays of 15-sec and 60-sec with varying numbers of containers.
• Behavioral data on hand and tail use were systematically recorded over 20 days.

Main Results:

• Spider monkeys demonstrated a consistent and robust left-hand preference during both learning and execution of DMTS tasks.
• Left-side tail use was occasionally observed, accompanying the left-hand preference.
• These results indicate lateralized motor control in the studied tasks.

Conclusions:

• The observed left-hand preference provides evidence for lateralized motor control in spider monkeys.
• This study contributes to the understanding of hemispheric specialization for working memory in nonhuman primates.
• Further research can explore the neural basis of this observed laterality.