Pigeons and people all bird brains

Studying the irrational and impulsive behaviour of pigeons could help to solve the mystery of why humans don't always act in their own best interests.

A study by Mike Colombo, an associate professor of psychology at the University of Otago, found pigeons don't like delayed gratification any more than we do.

The research could one day lead to a treatment for impulsive behaviours such as problem gambling or attention deficit disorder.

"The avian brain might look very different from the human brain, but they process information in much the same way we do," Professor Colombo said.

The experiment involved trained pigeons which were offered a choice of left or right "response keys". Pecking the left one produced a small food reward, the right one, a large reward.

To begin with, both keys produced a food reward at the same time, but gradually the larger food reward was delayed.

At first the birds pecked for the big reward, but the longer they had to wait, the more often they went for the smaller reward instead.

"At some point the bird just thinks, 'That's it, I'm not going to wait for the large reward, I'm going for immediate gratification'," Dr Colombo said.

"That's what we do as humans, it's an impulse. The better option would be to wait for the delayed reward, it's more."

The researchers measured the electric impulses in the pigeons' brains to find out exactly what happened when they made the decision not to wait for the larger reward.

Particular neurons showed increased activity as the bird anticipated a reward, and the larger the reward, the bigger the brain activity.

When the larger reward was delayed, activation of the neurons in the brain fell, which coincided with the decision to take the small reward.

"We found the cells that basically code for when the animal wants to shift away from a long-delayed reward to an immediate reward," he said.

"Once you find how the brain is coding for impulsive behaviour, you open up many more possibilities for research and cure."

Some pigeons were definitely more impulsive than others, he said, "just like humans".