In experiments asking fruit flies to distinguish between ever closer concentrations of an odour, the researchers found that the flies don't act instinctively or impulsively. (Agencies)
Instead they appear to accumulate information before committing to a choice.
Gathering information before making a decision has been considered a sign of higher intelligence, like that shown by primates and humans.
"Freedom of action from automatic impulses is considered a hallmark of cognition or intelligence," said Professor Gero Miesenbock, in whose laboratory the new research was performed.
"What our findings show is that fruit flies have a surprising mental capacity that has previously been unrecognized," said Miesenbock.
The researchers also showed that the gene FoxP, active in a small set of around 200 neurons, is involved in the decision making process in the fruit fly brain.
The researchers observed Drosophila fruit flies make a choice between two concentrations of an odour presented to them from opposite ends of a narrow chamber, having been trained to avoid one concentration.
When the odour concentrations were very different and easy to tell apart, the flies made quick decisions and almost always moved to the correct end of the chamber.
When the odour concentrations were very close and difficult to distinguish, the flies took much longer to make a decision, and they made more mistakes.
The researchers found that mathematical models developed to describe the mechanisms of decision making in humans and primates also matched the behaviour of the fruit flies.
In experiments asking fruit flies to distinguish between ever closer concentrations of an odour, the researchers found that the flies don't act instinctively or impulsively.