Poker machines are designed to elicit the same response in the brain "as people with a cocaine dependency", with the industry spending millions a year on research to make them even more addictive.
Federal senators Nick Xenophon and Larissa Waters, and independent MP Andrew Wilkie, launched their 'PokieLeaks' campaign on Tuesday calling for information on the gambling industry.
"What tricks are they playing?" Wilkie asked. He cited strategies like "false wins", where the machines play loud music and flash bright lights as if in celebration even when the 'win' is less than the cost of the spin.
It got us thinking about the 'tricks' the machines employ to get people addicted. Australia had around 200,000 poker machines in 2013-14, the highest rate per capita in the world. Australians lost more than $11 billion on machines last year, around $1200 per person. Hundreds of thousands of Australians are already, or at risk of becoming, problem gamblers.
Dr Charles Livingstone, at Monash University's school of public health and preventative medicine, is one of the world's leading researchers and experts on poker machines. He says those startling figures are all by design, with gaming machines purpose-built to get people hooked through "reinforcement events" -- a fancy name for the ringing bells, flashing lights and vividly coloured spinning reels that fill pubs, clubs and casinos around the country.
"The reinforcement events give a release of dopamine. It floods reward pathways in the brain. We see the same response in people with a cocaine dependency," Livingstone told The Huffington Post Australia.
"The more reinforcement, the greater the sense of anticipation, the greater the dopamine."
Livingstone says poker machines use two types of reinforcement to keep people playing, and keep them pouring money into the slots; classical conditioning, and operant conditioning. The classical type is the one more widely known as the Pavlov's dog scenario, where humans and animals can be trained to associate a certain event (in Pavlov's experiment, a ringing bell; with poker machines, a flashing light or happy music) with a reward (the dog gets a treat; the human gets a poker machine payout). Operant conditioning is a bit more tricky, teaching a human or animal to complete a task (pull a level or push a button) which will give only occasional and random rewards.
"If you want to habituate the animal or person, it's better to give them unpredictable and intermittent rewards," Livingstone said.
There lies the crux of the appeal of poker machines; you press a button or pull a lever, and most times you won't win, but the appeal and lure that the very next spin could maybe perhaps win a big jackpot keeps you playing.
"It makes it more addictive. It's all about increasing the reinforcement without forking out more money," Livingstone said.
He said the rest of the poker machine's tricks -- of which there are many -- stem from that. Lights and celebratory music go off and tout a win even when a $1 bet returns a 20-cent reward; gamblers are enticed to bet on many lines at once, thereby increasing their initial outlay, with 'near wins' where the required winning icons are often found just above or below the lines they had already bet on, hinting that they were so close to a jackpot and to bet more next time.
"Half the reinforcement from the wins and the other half is provided by these losses disguised as wins. You double the amount of reinforcement," Livingstone said.
"You get that dopamine response, you're halfway to addiction."
The lights and music themselves are also fine-tuned to maximise the reinforcement. Livingstone said composing music for poker machines is a full time job for some employees, and is a key part of getting people interested.
"It's dramatic, "ta-da", congratulatory. The music you associate with having a good time... Addicts say the music keeps ringing in their mind, they dream about it," he said.
"You walk into a gambling room, there's lots of machines on the floor, it seems like theyre all going off at once. At an unconscious level, it seems everyone is getting on it and having a good time and you should get on it too."
Even the themes of the poker machines are geared toward roping people in. Livingstone said poker machine companies market certain machines toward women and men in different ways; dolphins and under-the-sea themes for women, adventures and warrior themes for men. The different machines targeted to each sex even give payouts in different ways. Livingstone said research has shown women are more risk-averse and prefer to get more regular, small rewards, while men are more inclined to take risks and will therefore be willing to play machines that pay out rarely but give a large reward.
Dr Jane Oakes, gambling service coordinator at the Turning Point drug and alcohol centre, said a "significant" number of those calling their gambling help hotline were addicted to poker machines specifically.
"Initially they are seen as fun. They're easy to play, they can start off as a fun social activity, an environment which is quite exciting with flashing lights," she told HuffPost Australia.
"For other people, external triggers like getting extra bills, or needing some extra money for something, sometimes see people try to win some money through gambling. Other people feel sad, depressed, lonely, excited their sports team won, and they get this desire to gamble. Some people feel quite sad and gambling helps them get relief from that. It's an escape, a temporary relief."
She said it was often difficult for gamblers to realise they have a problem, let alone start to seek help, but that it was important to start. Oakes said Turning Point ran an online gambling help portal (click here) where people could anonymously assess their risk, seek help, get advice and information, or start an online chat with a counsellor.
"Help is really important, getting the confidence to join a forum and talk about their problems. Support and hope are important, it takes a lot of courage to call someone and ask for help," she said.
"There are a lot of services where people are trained, confidential and free, with financial consellors too. [Gamblers] often have high levels of anxiety depression stress. It's important to seek that immediate help."
For more information on Turning Point or about gambling addiction, call 1800 858 858 or see Turning Point's website.