Rat Slot Machine (rSMT)

Gambling is a culturally and socially ubiquitous phenomenon. The vast majority of us have easy access to gambling opportunities and will gamble at some point in our lives. For most people this is relatively harmless and generally doesn’t involve anything more than losing a few bucks playing poker. But for some, gambling can become a maladaptive compulsion similar to drug or alcohol addiction. We are interested in what predisposes some people toward the development of this kind of pathological gambling. Using an animal model of slot machine play, we have discovered that rats share key features of game play with humans. Namely, rats, like people appear to be susceptible to the ‘near-miss’ effect. ‘Near-misses’ are unsuccessful outcomes that are proximal to a win, such as matching two items on a slot machine pay-line and the third item just missing. Although people find these types of trials irritating, near-misses reliably galvanize game play, keeping people playing for longer and consequently spending more money. We are interested in elucidating the neurobiological basis for cognitive biases such as the ‘near-miss’ in order to potentially inform potential treatment options for human gamblers. We have data that the dopamine D4 receptor may modulate the erroneous expectations of reward that are thought to underlie the ‘near-miss’ effect, and experiments are ongoing in order to identify specific brain regions that might also be important.


Cocker PJ, Le Foll B, Rogers RD, Winstanley CA. A selective role for dopamine D₄ receptors in modulating reward expectancy in a rodent slot machine task. (2014). Biological Psychiatry.

Winstanley CA, Cocker PJ, Rogers RD. (2011). Dopamine modulates reward expectancy during performance of a slot machine task in rats: evidence for a ‘near-miss’ effect. Neuropsychopharmacology.