The Road Not Taken: Rodents Rue Bad Decisions

Two rats eatingThe past weekend I switched lines in the grocery store only to regret it a few seconds later when another shopper with an enormous cart got there before me and I had to wait an additional 20 minutes for the cashier to fix a problem with the register. Sound familiar? As far as I know rodents do not shop in the stores that I do but it seems that a rat might have felt the same in my place. Or so say a team of scientists from the University of Minnesota out to study decision-making abilities in rats. 1

Regret is the ability to recognize a mistake in the choices made and reflecting on the counter-factual: what might have been. It is different from disappointment, an emotion associated with when reality does not live up to expectations. To demonstrate the ability of higher cognitive skills in our favorite laboratory animal, Neuroscience Professor David Redish and his team set up a test called “Restaurant Row” which consisted of a circular runway with four spokes each leading to a different flavor of food.  As the rat came to the entrance of each spoke, a tone sounded that indicated how long it would have to wait to receive that specific flavor of food. The rat could choose whether to stay or go, depending on how much it liked that food and how long it would have to wait. Akin to deciding that the line in your favorite restaurant is too long and choosing to eat at a fast food chain across the street instead, sometimes the rats decided to skip the long wait at one restaurant that offered their favorite food only to find the next one had a longer wait time or was a bad deal.

The authors hypothesized that if the rat had left a restaurant because the wait time was above its established threshold and then had to wait again at the next stop, it should feel disappointment, rather than regret. After all, it was a reasonable decision to skip the lengthy wait and move on to the next stop on the restaurant wheel. On the other hand if the rat had left a restaurant that had a waiting time below its threshold, only to encounter a lengthier wait at the next spoke, it had genuinely erred in its judgment.In these situations, the rat stopped and looked back at the previous restaurant it had passed as if feeling regret.

Upon further analysis of their behavior under disappointed and regret circumstances, the rats showed three behaviors consistent with regret. First, the rats only looked backwards in the regret conditions, and not in the disappointment conditions. Second, they were more likely to take a bad deal if they had just passed up a good deal. And third, instead of taking their time eating and then grooming themselves afterwards, the rats in the regret conditions rushed through their meal much like a regretful human would.2,3

Redish also used minute electrodes to record neural activity in the rats’ orbitofrontal cortex (OFC), an area of the brain that is active in the human experience of regret. People with damage in this area often do not experience regret.Using a computer algorithm the team found that neurons in the OFC fired in a pattern associated with the previous restaurant when the rats were looking backward, suggesting that the rodents were indeed preoccupied with what might have been.4

Although their behavioral and neurophysiological results suggest similarities to human regret, we do not know if rats have the same introspective experience of regret as humans. This study, showing that rats show regret, is an important step forward for animal behaviorists and neuroscientists alike because for the first time regret has been identified in species other than humans.The insights gleaned from here could help improve animal models of bad decisions, such as drug or alcohol abuse because addiction can be viewed as decision-making gone wrong. No word, however, on whether rats feel regret for the mess they create, diving into the dumpsters outside your favorite restaurant!

 

References:

  1. Steiner, A. P. and Redish, D. (2014). Behavioral and neurophysiological correlates of regret in rat decision-making on a neuroeconomic task. Nature Neuroscience, June 8, 2014. doi: 10.1038/nn.3740.
  2. Emily Underwood. (2014).Rats Regret Bad Decisions. Posted in Brain and Behaviour.
  3. Mary Bates. (2014). Rats Regret Making the Wrong Decision.
  4. Steiner AP1, Redish AD. (2012). The road not taken: neural correlates of decision making in orbitofrontal cortex. Front Neurosci. 2012 Sep 11;6:131. doi: 10.3389/fnins.2012.00131.
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Radhika Ganeshan

Technical Services Scientist at Promega Corporation

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