Bigger brains could help us see better, according to academics.
Psychologists have discovered that increasing the size of the brain is associated with enhanced visual processing - meaning that finer details can be seen.
Researchers at the University of Bath found that an ever-increasing brain, such as an expanding visual cortex, was an essential element of evolution.
Dr Alexandra de Sousa and Dr Michael Proulx said it was controversial as to whether overall brain size can predict intelligence.
But their work with different primate species, including humans, apes and monkeys, found the size of specialised areas within the brain is associated with specific changes in behaviour - such as reducing the susceptibility to visual illusions and improving the view of finer detail.
Dr de Sousa explained: "Primates with a bigger visual cortex have better visual resolution, the precision of vision, and reduced visual illusion strength.
"In essence, the bigger the brain area, the better the visual processing ability.
"The size of brain areas predicts not only the number of neurons - brain cells - in that area, but also the likelihood of connections between neurons.
"These connections allow for increasingly complex computations to be made that allow for more accurate, and more difficult, visual perception.
Co-author Dr Michael Proulx added: "This paper is a novel attempt to bring together the micro and macro anatomy of the brain with behaviour.
"We link visual abilities, the size of brain areas, and the number of neurons that make up those brain areas to provide a framework that ties brain structure and function together.
"The theory of brain size that we discuss can be tested in the future with more behavioural tests of other species, gathering more comparative neuroanatomical data, and by testing other senses and multi-sensory perception, too.
"We might be able to even predict how well extinct species could sense the world based on fossil data."
For the study, Dr de Sousa, an expert in brain evolution, provided brain size measurements from her and others' neuroanatomical research.
Dr Proulx, an expert in perception, found psychological studies of visual illusions and visual acuity in the same species or general of animals.
:: The paper, What Can Volumes Reveal About Human Brain Evolution? A Framework For Bridging Behavioral, Histometric And Volumetric Perspectives, is published in the journal Frontiers In Neuroanatomy.