If you’ve got a weakness for gambling, you might try to explain your vice away by saying “I’m only human.” But it turns out that chancing your luck is something other species do.

According to researchers from the University of Kentucky, pigeons also like to gamble, even when the odds are against them.

Professor Thomas Zentall and Jessica Stagner carried out an experiment into what they call maladaptive choice behavior: that is, not altering actions even in the face of increasing evidence to show the choices being made are wrong. (Insert political satire here.)

The experiment involved pigeons being given the repeated opportunity to peck on one of two keys, one with vertical lines and one with horizontal lines. Their choice would prompt a colored light to display (red or green for the vertical line key, blue or yellow with the horizontal line key.)

What the pigeons didn’t know, but should have eventually figured out is that whenever they chose the key with the horizontal line, they always unveiled three food pellets, regardless of which color light appeared.

With the vertical line key, they got 10 pellets if the green light appeared, but nothing if the red light appeared. The system was set up so that the green light appeared only 20% of the time.

If you analyze those odds objectively, picking the horizontal line key would give the pigeon three pellets on average (and indeed, every time.) Picking the vertical line key would give an average of two pellets each time. However, six of the eight pigeons in the test showed a clear preference for the vertical line key.

The researchers then repeated the experiment with one tweak: although picking a vertical line key still had a 20% chance of unveiling 10 pellets (and an 80% chance of unveiling nothing), the green and red lights appeared randomly and no longer had any relation to the pigeon’s reward, or lack of it. This time round, all the pigeons figured out that the horizontal line key was the smarter option.

And the researcher’s conclusion? Pigeons are capable of making rational probability decisions in what are effectively gambling situations, but this decision making process can easily be overriden by the pigeons placing far too much weight into the link between flashing colored lights and perceived reward.

And if you think we humans are too smart to fall for that one…

(Image credit: Flickr user JenT)