Islamabad( The COW News Digital)A groundbreaking study has revealed that primates with proportionally larger thumbs also tend to have larger brains, particularly in the neocortex region responsible for higher cognitive functions. The research provides new insights into the connection between hand morphology and brain evolution.
Led by Dr. Joanna Baker from the University of Reading, the study analyzed 94 primate species, including lemurs, ancient hominins, and humans. Researchers measured thumb size relative to hand proportions and examined corresponding brain volumes. The findings consistently showed that primates with larger thumbs have a bigger neocortex, suggesting a link between thumb development and advanced cognitive capabilities.
Interestingly, the study found that this relationship holds true across primates even when human data is excluded. The neocortex, involved in awareness, sensory processing, and planning, appears more influenced by thumb size than the cerebellum, which is primarily responsible for movement and balance. This challenges previous assumptions that motor coordination alone would drive brain enlargement in relation to thumb size.
The research highlights how manual dexterity and brain evolution are closely intertwined. As primates became more skilled at manipulating objects with their hands, the neocortex expanded to support complex behaviors such as planning, problem-solving, and conscious decision-making. Larger thumbs likely facilitated improved grasping, tool use, and fine motor skills, driving cognitive development over evolutionary time.
Dr. Baker explained, “Our study suggests that hand morphology is not just a matter of physical adaptation but also plays a significant role in shaping the brain. The larger the thumb relative to the hand, the more capacity the neocortex has to support complex thinking and behaviors.”
The findings could provide valuable insights into human evolution, particularly the development of manual skills and cognitive abilities. Understanding how physical traits like thumb size influence brain structure can shed light on the evolutionary pressures that shaped modern humans and other primates.
This research underscores the importance of considering physical adaptations alongside neurological development when studying primate evolution. It also opens the door for further studies into how manual dexterity and intelligence co-evolved in humans and their primate relatives.
