Casino for Rats Sheds Light on Slot Machine Design

Science news is full of ‘no duh’ announcements, often confirming what seems like common sense.

But since furthering our understanding in any given field comes by way of empirical evidence, these seemingly predictable results can often lead to more groundbreaking ones.

A recent example is research from the University of British Columbia that sheds further light on when and how we gamble. The study by Michael M. Barrus and Catharine A. Winstanley observed how lab rats interacted with a proverbial ‘rat slot machine’ under a variety of different circumstances.

A rat playing slot machines at a casino
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While the study’s results might have confirmed what many already suspected, the degree to which it did should make us aware how seemingly little details can impact our gambling behavior in big ways.

Introducing The Iowa Gambling Task

Barrus and Winstanley’s study was built upon the famous Iowa Gambling Task experiment. Conducted in 1994 by researchers at the University of Iowa, the landmark study presented participants with four decks of cards on a computer screen.

In the test players had the freedom to choose which deck they wanted to receive a card from next, however some decks were stacked with cards that would reward a player with virtual money while others were loaded with ones that penalized them, taking said money away.

The display from the Iowa Gambling Task experiment
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With the goal being to win as much money as possible, most participants figured out which were the high and low risk decks after 40-50 draws. However, participants with orbitofrontal cortex and prefrontal cortex dysfunction did not experience the same stress levels other players did when drawing a harmful card, instead showing behavior that favored big immediate gains even when the potential risk was also large.

The BC Rat Casino

Using a similar methodology, the University of British Columbia study gave the 32 rats in their experiment four different ‘options’ to choose from, triggered when a rat poked their nose in one of five different holes.

A poke in four of the holes would release an assigned number of sugar pellets (1-4) in a nearby food tray. Depending on which options the rat triggered, a corresponding ‘time out’ would then take place, ranging from just five seconds for the one-pellet hole to 40 seconds for the four-pellet hole.

The British Columbia study testing rats in a gambling experiment
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This simulated the pull of high risk, short-term gratification versus low-risk, long-term gratification, as during the 30 minute session the two-pellet hole (with a timeout of 10 seconds) had a maximum potential yield of 411 pellets versus just 99 pellets for the four-pellet, 40-second timeout hole.

In the first of two sessions for each rat, the animals learned quickly which holes to avoid for optimal payout amount and timeout time. But when researchers added flashing lights and sounds–the higher the pellet payout, the more intense–the rats’ behavior changed dramatically.

Thanks to these audial and visual cues, the rats chose the more disadvantageous options more frequently. This backs what many have suspected about one of casinos’ oldest tricks–flashing lights and sounds attached to winning results keep players playing longer and in riskier ways.

The Effect of Amphetamine and Dopamine Blockers

A real money slot machine
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The researchers then repeated this experiment, this time injecting the rats with either an amphetamine or one of five different dopamine blockers. Dopamine of course is a ‘feel-good’ chemical released in our brain when we participate in a rewarding behavior, be it eating delicious food, playing video games, having sex, or gambling.

The rats amped up on amphetamine didn’t react differently in the version of the experiment with the sounds and flashing lights. Although, in the silent version there was a big increase in preference to the option that gave out just one pellet but had the shortest wait time.

The effects of drugs on rats during the experiment
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The results were much more interesting in the experiment using the dopamine-blockers. In some of the dopamine-blocking concoctions, the rats were much less averse to be influenced by the lights and sounds or engage in riskier behavior. The effects of the dopamine stoppers were solidified when it showed no real effect on the rats in the more version of the experiment.

Using the Rats (And Results) For Good

To the lay observer, that flashing lights and stimulating noises increase risky gambling behavior might not be news. Winstanley herself even says, “I often feel that scientific models are decades behind the casinos,” and that, “anyone who’s ever designed a casino game or played a gambling game will tell you that of course sound and light cues keep you more engaged, but now we can show it scientifically.”

But being able to show the degree to which A/V cues impacted the rat’s brain could lead to further important breakthroughs about the nature of addiction.

“This brain receptor is also really important to drug addiction, so our findings help support the idea that risky behavior across different vices might have a common biological cause,” says Barrus.

While there would be certain ethical challenges, repeating these same results in humans could potentially impact gambling legislation and the techniques that game designers and casinos can use.

Removing audio and overly-sensational visual cues from slot machines might lead to a dip in participation (and casino profits), it could also be key in reducing the rate of problem gambling in the world.