Summary: Koboroff et al. (2008)

The two hemispheres of the brain are able to conduct different functions, an ability known as brain lateralization. In birds, brain lateralization has been inferred when a preference to observe a stimulus with one eye ("lateral monocular visual field" is observed. Koboroff et al. (2008) considered that Australian magpies (Gymnorhina tibicen) would show eye preferences when performing anti-predator response. Constant assessment is needed during mobbing behaviour, to make decisions regarding approach, mob or withdraw. They speculated that the left hemisphere would control approach, while the right hemisphere would control withdrawal. However, since mobbing is considered a strong agonistic response, this could be controlled by the right hemisphere (controls intense emotion). Monocular fixations prior to or during performance of mobbing activity in response to perceived predation threat were video recorded. Koboroff et al. (2008) found that, prior to withdrawal, magpies favoured the left eye (85%), while prior to approach, magpies favoured the right eye (72%). Hence, approach in magpies is controlled by the left hemisphere, while withdrawal is favoured by the right hemisphere. They speculate that the left hemisphere is used to process visual inputs prior to approach and the right hemisphere prior to withdrawal. Their results are consistent with hemispheric specialisation in other species, including humans. The relationship between predator-prey interactions and the right hemisphere suggest that the right hemisphere may have, over evolutionary time, organised various anti-predator strategies.