The Differences in Ape & Human Brains

Anatomy

• The human brain is physically larger than the brain of an ape. While the average brain of a great ape weighs between 300 and 500 grams, the average human brain weighs in at 1,300 grams. Furthermore, scientists at UCLA have discovered that the human's cerebral cortex, known as the "most highly evolved region" of the brain, is three times larger than the ape's. This is also the area of the brain where the gene networks differ most drastically between humans and great apes.

Rate of Development

• While all other primates double their brain weight in the time between birth and maturity, humans actually triple their brain weight. This is due in part to the "prematurity" of human births, in relation to other species of ape, which are precocial, or more independent after birth. Because humans are born earlier in the developmental stage, the majority of fetal brain development occurs outside the womb. This means an exponential increase of sensory input, which creates an upsurge of neural connections in the brain.

Speech and Communication

• The difference of size and complexity in ape and human brains means a difference in speech and communication. Apes have demonstrated an ability to understand and respond to spoken commands, and can even communicate basic phrases using computer touchscreens. However, their brains are not designed to hold extensive conversation. In April 2010, neurobiologists at UCLA studied the properties of a gene called FOXP2, found in both chimps and humans. This gene is connected to human language, and is found in similar forms in humans and chimps, differing in only two locations out of 715. However, the differences are significant enough to prevent the ability for speech in an ape's brain.

Social Behavior

• Jared Taglialatela, a biologist at the Yerkes National Primate Research Center, has commented on apes' impulsive behavior. They respond in the moment to external stimuli, and have no sense of social context or self-control. This is largely due to a difference in activity in the frontal lobe, the part of the brain that allows humans to control their impulses. While a human's frontal lobe may not be proportionately larger than an ape's, the frontal lobe of a human possesses significantly more neural connections, which translates into greater self-control.