"Brain asymmetry is essential for proper brain function," explains Professor Wilson. "It allows the two sides of the brain to become specialised, increasing its processing capacity and avoiding situations of conflict where both sides of the brain try to take charge.
"For example, faced with a predator, an animal would not want both sides of the brain to try to drive the escape as this might lead to conflict over which direction to turn. Instead, the animal might keep watch more with one eye (and consequently one half of the brain) and so each side of the brain might be dominant for particular activities."
Previous studies have shown that rearing chickens in the dark makes their brains less asymmetric. The chicks can still peck for food and watch out for predators, but only if doing one of these tasks at a time. When they try to do both, they are less efficient than fully asymmetric animals in which one eye specialises for one task and the other eye for the other task.
In humans, people with schizophrenia have disrupted brain asymmetries but as yet, it is not clear if there is a causal link between the asymmetry and schizophrenia.
"The direction and handedness that brain asymmetry takes is not critical for survival, but the strong bias towards one direction may be to ensure that all members of a population have consistent behaviours," adds Professor Wilson. "This may be very important for social animals, such as humans and schooling fish."
|Contact: Craig Brierley|