Pigeons quicker in multitasking than humans

London : Despite their small brains, pigeons are capable of switching between two tasks as quickly as humans - and even quicker in certain situations, new research has found.

The researchers believe that the cause of the slight multitasking advantage in birds is their higher neuronal density.
For the study, published in the journal Current Biology, the researchers performed the same behavioural experiments to test birds and humans.

"For a long time, scientists used to believe the mammalian cerebral cortex to be the anatomical cause of cognitive ability; it is made up of six cortical layers," said Sara Letzner from Ruhr-Universitat Bochum in Germany.

In birds, however, such a structure does not exist. "That means the structure of the mammalian cortex cannot be decisive for complex cognitive functions such as multitasking," Letzner said.

The brain pallium of birds does not have any layers comparable to those in the human cortex, but its neurons are more densely packed than in the cerebral cortex in humans.

Pigeons have six times as many nerve cells as humans per cubic millimetre of brain. Consequently, the average distance between two neurons in pigeons is fifty per cent shorter than in humans.

As the speed at which nerve cell signals are transmitted is the same in both birds and mammals, researchers had assumed that information is processed more quickly in avian brains than in mammalian brains.

They tested this hypothesis using a multitasking exercise that was performed by humans and pigeons. In the experiment, both the human and the avian participants had to stop a task in progress and switch over to an alternative task as quickly as possible.

"Researchers in the field of cognitive neuroscience have been wondering for a long time how it was possible that some birds, such as crows or parrots, are smart enough to rival chimpanzees in terms of cognitive abilities, despite their small brains and their lack of a cortex," Letzner said.

The results of the current study suggest that it is precisely because of their small brain that is densely packed with nerve cells that birds are able to reduce the processing time in tasks that require rapid interaction between different groups of neurons.