You know the story well: You spend a good 45 minutes debating whether or not to go out in the first place because you're still paying off last month's credit card bills, but three hours and a bottle and a half of wine later, you're buying shots for every man and his dog in the bar—including the toilet assistants who aren't even on a night out.
It happens every time. There's a moment—and the turning point always goes undetected—when your mind switches from being sensible and spending in accordance with the very distressing state of your bank account, to being completely and utterly reckless. You can afford another bottle of prosecco, you tell yourself. You can just bring baon in the coming weeks anyway.
But why do we do it? Because all it serves to do is make your hangover feel worse the next day when you realise you can't afford to buy food to make it better.
To determine the reasons behind this baffling bodily phenomenon, we spoke to Dr. Seth Rankin of London Doctors Clinic to give us the lowdown on what actually goes on in those fickle, inebriated minds of ours.
These, he says, are the reasons we're more likely to splash the cash when we're all boozed up.
1. Memory Loss
Memory loss doesn't just occur the next day when you realise you can't remember how you got home; Dr Seth reveals we can also suffer from short-term memory loss while we're on the night out. You may not notice it at the time, but it often goes something like this… "Oh no, where's all my cash gone?!" "You spent it on Jaegerbombs" "… Did I? Oh well. Should we get more Jaegerbombs?"
Sadly, that conversation is all too familiar, but in the world of medicine, these are known as either 'partial' or 'complete memory blackouts,' explains the doctor. The more you drink, the more significant these are.
2. Drinking makes you forget your worries
And along with your worries, you also seem to forget about your wealth of monthly outgoings, including direct debits, rent, mortgage, phone bill, Netflix subscription, and your inevitably eye-watering credit card bill. A glass or two of alcohol has been shown to ease anxiety—in the short-term at least—which makes you far more carefree about all the responsibilities you've got.
3. You develop an inability to calculate
You might not be a mathematician on a good day, but you're even less likely to be able to gauge (a) your financial situation or (b) the cost of this rather large round of drinks, after you've had a few yourself.
"Alcohol has been shown to affect your 'working memory'—the part of your brain which temporarily holds information for processing," says Dr Rankin, "so the chances of remembering your running total long enough to add a few more drinks is slim to none."
4. Drinking unleashes your inner social butterfly
You wouldn't usually offer to buy a drink for your friend's weird new partner in the sober light of day, but hey, you're feeling merry and he suddenly feels like your new best friend.
"Some may call it alcohol-related-disinhibition, others call it alcohol-induced-friendliness," says Dr Seth. "Whatever you want to call it, studies have shown that alcohol makes peoples' social behaviors and responses more extreme or excessive than if they were sober."
5. You want to assert your dominance on the group
"Alcohol has been known to increase aggression in some people, with more alpha-male and female behaviors seeping out the more you drink," says the doctor. "And the best way to assert your dominance on the group? Buy them drinks!"
"If you buy the rounds," he explains, "you'll get both the attention and gratitude of your group, which you can perhaps use to your advantage in future."
6. The generosity inflates your mood
"Although you may feel happier while drinking, alcohol use is associated with depression, especially in the long-term," Dr Rankin explains. "While some people use food or illicit drugs as a pick-me-up when they're feeling low, others may achieve short-term happiness from actions such as buying a round of drinks. You may not realise it, but you're habit of buying drinks for others may stem from the need for satisfaction associated with their gratitude.
"Sadly, this gratitude is often short-lived," he adds, "as the chances are in ten minutes' time, they're not going to remember who paid for the drink in their hand." It's sad but it's true.
Now try not to spend quite so much on your next night out, okay?
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This article originally appeared on Cosmopolitan.com/uk. Minor edits have been made by the Cosmo.ph editors.