14 DAY TRIAL // In laboratory conditions, researchers test various aspects of lab rats' behavior, in a bid to find parallels between their way of acting in certain situations and our own. Once this happens, they find an animal model for a certain human trait, various aspects of which they can analyze. In a recent investigation, scientists turned their attention to how mice and rats chose their options in a gambling task. They had to make certain choices, which earned them various rewards, some larger and some smaller. The results revealed that the rodents avoided high-gain options, because they also carried risks.
In fact, the science team noted, most of the rats in their experiments avoided the most rewarding options, because they carried the highest risks. For instance, while selecting such an option could have earned them a large sugar treat, failing it would have deprived them of the sweet stuff for a prolonged period of time.
So, they preferred selecting less-advantageous options, but which carried a much larger rate of success, and less severe punishments. The finds open up new avenues of research in game theory, and they also provide experts with an animal model for studying neuropsychiatry.
The researchers based their experiment on an existing clinical trial, known as the “Iowa gambling test.” The rodents were placed in a cage, which gave them four options, in the form of holes to investigate. Each of the holes could be triggered to offer either reward (sugar treats), or penalties (time-out periods during which treats could not be earned). Some of the holes offered more sugar pellets at once, while also having a higher chance of penalties, while others offered less sugar, but carried a much lower chance of punishment as well.
The behavior of the animals amazed the researchers. The rats soon learned that the high-gain holes were the most dangerous, and preferred maximizing their gains not all at once, but through repeatedly going to the holes that offered less rewards but higher success rates, University of Cambridge expert Trevor Robbins, one of the leaders of the new study, said. When the team gave the rats drugs that inhibited their levels of dopamine and serotonin, two hormones that regulate addiction, the animals started making disastrous decisions.
“Not only have we seen that our rats will gamble, but we've also been able to modulate that behavior. This coincides with data we've seen from pathological gamblers, who have been shown to have lower levels of serotonin in their brains. We also found that we could make our rats better gamblers by giving them a dopamine receptor antagonist – a drug that reduces the effects of the neurotransmitter dopamine,” University of British Columbia expert Catharine Winstanley, the lead author of the new research, published in the latest issue of the scientific journal Neuropsychopharmacology, explained for the BBC News.