Our brains are naturally configured to get pleasure out of some of the things we do. That's why we survive.

Pleasure drives us to hit some crucial day-to-day goals, such as finding and eating food.

But the system as a whole is more complicated than that; it's not all about tangible rewards.

We can spend an awful lot of time pursuing a pleasurable experience that is far from "mission critical" — like discovering how a piece of machinery is assembled, or nutting out the pattern to a sequence of symbols.

This kind of puzzle can be frustrating, but the pleasure of eventually solving it spurs us on — and crucially, our brains process the anticipation of that understanding as a form of pleasure.

Chemically, even though we've done nothing useful, this is the same reward we get for achieving a survival goal.

And it's that anticipatory pleasure pathway which goes into overdrive when we gamble. It can lead us to a place that addicts call "the zone", where even winning the jackpot is a distraction from the game.

A well studied, very ingrained system

Dr Charles Livingstone, a gambling researcher from Monash University's School of Public Health and Preventive Medicine, says the brain's method of producing these rewards has a lot to do with two well-known forms of psychological conditioning.

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The first is operant conditioning — made famous by psychologist BF Skinner in the 1950s.

Skinner experimented with pigeons, and noted that they would readily peck at a spot if they were rewarded with food. Crucially, the reward was not given at every peck; that allowed Skinner to investigate what he called the "schedule of reinforcement".

"Skinner used rats and pigeons but humans are equally susceptible," says Dr Livingstone.

"If you give them a predictable set of rewards, then they lose interest quite quickly; if it's unpredictable, they tend to establish behaviour which is very hard to extinguish."

The second manipulation is called classical conditioning — discovered way back in the 19th century by Anton Pavlov. He found that feeding a dog, and associating that food with a sound, meant that the dog would eventually salivate at the sound alone.

Pavlov's famous experiment proved you could condition dogs with sound — and the same may be true for humans ( Pexels: Kat Jayne )

According to Dr Livingstone, gambling machines wrap together both types of conditioning: they offer rewards at unpredictable intervals, and they pair those rewards with encouraging noises and lights.

Designing for dopamine — the brain's internal bribe

"In recent times we've discovered that the mechanism by which these two principles operate is through the brain's reward circuit," he explains.

The critical neurochemical in that circuit is dopamine; it gets secreted both when we anticipate a reward, and when we get one.

"This is a very old part of the brain, so animals like rats and pigeons and all sorts of animals are in exactly the same position as we are," says Dr Livingstone.

"And it works because it provides you with a sense of euphoria and a reward sense — which is necessary when you are scrapping for survival out on the veldts of Africa."

It's also highly addictive. The dopamine release is what keeps people going back to addictive drugs like cocaine, Dr Livingstone says.

And over the past 100 years or so, the architects of gambling environments have become masters at utilising this chemical cycle in our brain — to the extent that gamblers really don't welcome anything which disrupts it, because it takes them out of their "zone".

"The zone was very much about flow and rhythm and repetition and just continuing," says Natasha Schull, a cultural anthropologist who spent many hours in the casinos of Las Vegas researching the design of gambling environments and the way gamblers behave.

She spoke to addicts who said winning a jackpot just made them feel annoyed.

"When they won, the machine would make a lot of jingling noises, it would freeze up and play victorious music, sometimes people would look over at them… Essentially it interrupted the zone."

A parallel universe with real-world consequences

Carolyn Hirsh is a former Victorian MP and psychologist, and was also a self-confessed gambling addict. She remembers the power of that psychological conditioning in action.

"There's the music, there is the sound when you win, and you think 'I've won', although you haven't — you've actually lost. But music plays," she says.

"People come around and give you free coffee and look after you, there's that nice feeling. But … I think the real thing is the way the machines are designed alters the brain."

These changes to the gambling brain can do a lot of damage. Being in "the zone" means being in an alternate universe, where family and responsibility don't seem important.

There's even data to show an association between areas with a large number of poker machines and the rates of particular kinds of crime, Dr Livingstone says.

Critics argue the lights and sounds of gambling machines condition users to continue playing ( Flickr.com: Reno Tahoe (CC-BY-NC-ND-2.0) )

"The harms of gambling include separation, fraud, financial disaster, divorce, violence and neglect of children," he says.

"They are associated with mental and physical ill health, and of course ultimately with suicide. Most people who experience gambling harm are too ashamed to admit that they have succumbed to such a silly addiction, as they see it."

The debate around these harms, and who is responsible, is intensifying.

Help for individuals is available through crisis support bodies, but the effect on communities means that gaming industry methods are inevitably drawn into the political arena.

Poker machines are shaping up to be an electoral issue in Tasmania as community groups, councils, unions and professional associations call for the machines to be removed from some venues.

And a former addict is suing a casino and a pokie manufacturer, arguing that a particular machine is deceptive and addictive.

With so many stakeholders in how the pokies operate, however, there's no obvious or easy fix for the problem.

Meanwhile, for those who gamble, the hard-wired allure of "the zone" is not going anywhere.