Most people who play Lotto have at least some kind of intuitive understanding they are probably not going to hit the jackpot.

You've probably heard you are far more likely to die driving to buy your ticket than you are to actually win first division.

So, if winning is very unlikely, why is playing the Lotto so popular? If people know something is very unlikely to occur, and it costs them to see if it will, why would they do it? There are several reasons - many rooted in psychology. Here are seven of the more common.

## 1. Near misses

Across just about any domain, there is a strange allure of "almost winning".

The near-miss effect describes a very special kind of failure to reach a goal. The player making the attempt comes close to, but falls just short of, hitting their goal.

In skill-based games like football or basketball, a near miss gives players useful feedback and a type of implicit encouragement - "you were so close, try again". This gives the player hope for success in future trials.

Lottery players who come close (maybe they get three or four numbers out of six right; the odds of this are generally less than one in 1000) take this as a sign they should keep playing - and they often do. A 2009 paper found near misses activate the same reward systems in the brain as actual successes.

## 2. The numbers are too big

Gambling studies professor Robert Williams suggests that although humans have evolved some appreciation for numbers, we don't really understand big numbers.

We deal with amounts like six, 24 and 120 all the time, but throughout history it's never really been important to measure out 18 million of something, or count 50 million of something else.

Odds of one in 200 million don't seem that different to odds of, say, one in 3 million. In both cases success is really unlikely.

Give someone a choice between odds of one in three and one in 200, however, and the difference is really obvious. It's certainly not that people can't grasp really big numbers, but that they don't have much meaning until we stop and think about them.

## 3. Availability heuristics

The availability bias/heuristic relates to the idea that people judge the likelihood of something based roughly on how readily examples of it come to mind.

For example, you can probably think of news stories about when a shark has bitten a swimmer. One reason is this kind of a story is sensational, and will likely be highly reported.

Because you can easily bring to mind examples of shark attacks, you might be tempted to conclude shark attacks are far more common than they actually are. In fact, the chances of being attacked by a shark are somewhere in the neighbourhood of one in 12 million.

You hear and read stories about lottery winners all the time but the battlers who have been playing for 20 years without winning are relegated to obscurity.

Based on this, it's at least reasonable to think "jackpotting" can't be that rare. The net effect is that winning seems possible.

## 4. The gambler's fallacy

If you are playing roulette in a casino and "red" has come up on all of the past 20 rolls, is the next number more likely to be red or black?

The gambler's fallacy is the mistaken belief that because an outcome hasn't occurred for a while it is (somehow) "due" to occur. In the above example, committing the gambler's fallacy would involve betting on black because it has to "come up" in order to balance out the average - since we know red is as likely to occur as black.

People frequently select Lotto numbers based on how often they come up - or, rather, how long it's been since they came up.

## 5. The sunk-cost fallacy

This is an extremely pervasive cognitive bias.

In economics, a sunk cost is any previous expense that can't be recovered - like a previous business expenditure on software, education, or advertising. Because this cost has already occurred and can't be recovered, it should no longer be factored into future decisions. But this is seldom the case.

The sunk-cost fallacy occurs when you make a decision based on the time and resources you have already committed.

In Lotto, people will often persevere with what they sometimes know is economically irrational - like buying more tickets - simply because they have already invested so much.

It's not just Lotto, though. Sunk costs result in irrational decision-making all the time.

How about deciding to stay in a bad relationship because you've already put so much into it? Or continuing to read a bad book or watch a bad movie just because you're already halfway through?

## 6. Your only chance

Some people realise there are long odds against winning Lotto, but the possible payout is seductive. Winning the lottery may be their only way out of social, economic or political hardship, for example. Research has found when times are tough, people are more willing to take risks - such as playing the Lotto. The potential payout may be so life-changing that it justifies the small cost of playing.

## 7. Entertainment

There are some people who intuitively realise that although playing Lotto may hold little economic value, it does have entertainment value. While you are unlikely to make a net monetary gain, you can get something else out of it.

It would be ridiculous to assume everyone is equally motivated by financial rewards and nothing else. People go to movies, concerts and sports events all the time with no expectation of financial gain.

From a purely economic perspective this behaviour may not seem as easy to account for a simple financial wager. Fortunately, humans are motivated by more than just money, and all kinds of seemingly "irrational" behaviour can be explained away fairly easily.

So, some lottery punters are seeking the thrill of the possibility of winning. Others are using it as a justification to temporarily fantasise about excessive wealth.

For less than the cost of a cup of coffee, one can realistically spend several happy hours imagining "what if". The excitement one may experience from even having a chance of winning may be enough to justify the cost of a ticket or two.

Ryan Anderson is a PhD Candidate, School of Arts and Social Sciences and David Mitchell is the Deputy Head and Lecturer in the Discipline of Psychology, James Cook University.