Latest / Behavioral Economics with Fexingo: Decision Making, Bias, and How People Really Spend / Why Your Brain Saves Money in Separate Mental Accounts
Transcript
- Lucas: So here's a question for you, Luna: imagine you've saved up a hundred dollars to buy a concert ticket. You walk into the venue box office, and you realize you lost the hundred-dollar bill on the way. Do you still buy the ticket? Luna: Hmm. I think most people would say no — it hurts too much to lose that money and then spend more out of the same mental bucket. Lucas: Exactly. Now imagine a different scenario: you planned to buy the ticket, but at the box office you realize you lost a separate hundred-dollar gift card that you'd been saving for something else. Do you still buy the ticket? Luna: I think a lot of people would say yes in that case, even though it's exactly the same net loss. That's fascinating. Lucas: That's the classic thought experiment from Richard Thaler, the Nobel Prize-winning economist who coined the term 'mental accounting.' And it's the subject of today's episode — why our brains create separate mental ledgers for different categories of money, and how that distorts our spending and saving decisions. Luna: So mental accounting is basically the informal, subjective accounting system we all run in our heads, where we assign money to different buckets — rent money, fun money, gift money — and then treat each bucket as non-fungible. Lucas: Right. In standard economics, money is fungible. A dollar is a dollar whether you earned it, found it, or received it as a gift. But behavioral research shows that we consistently violate fungibility. We treat a tax refund differently from a bonus, even if both are unexpected windfalls. Luna: And one of the most striking examples is the gift card effect. Studies show people are willing to spend more freely with a gift card than with cash, because it's mentally categorized as 'free money' or 'fun money.' Lucas: There's a famous field experiment from the late 2000s where researchers gave shoppers either a $10 cash voucher or a $10 gift card. The gift card recipients spent an average of $2.60 more on indulgent items than the cash recipients. The same dollar amount, but the mental label changed the behavior. Luna: So it's not just about the dollar — it's about the story we tell ourselves about that dollar. Lucas: Exactly. And Thaler's original paper in 1985 laid out a simple framework: we have current income, current wealth, and future income, and we set up mental budgets for each. A windfall — like winning fifty dollars on a scratch-off — gets coded as 'current income,' but often into a sub-account like 'play money.' Luna: Meanwhile, a regular paycheck goes into the 'serious money' account. So you might blow a lottery win on dinner out, but you'd feel guilty using a bonus from work the same way. Lucas: Right. And the problem is, this mental accounting can lead to suboptimal financial outcomes. Take the classic case of borrowing on a credit card at eighteen percent interest while simultaneously saving in a low-interest savings account. Logically, you should take the savings and pay down the card. But mentally, the savings is for 'emergencies' or 'the future,' and the credit card debt is 'monthly spending.' Luna: There's a study from 2007 that found exactly this: about a third of U.S. households with credit card debt also had liquid savings that could have paid off that debt. They were literally paying extra interest to maintain a mental separation. Lucas: And that's not irrational in an emotional sense. The mental separation provides a feeling of security. But it's costly. Thaler himself argued that we can use mental accounting to our advantage — by deliberately creating mental accounts that help us save. Luna: Like the 'envelope system' for budgeting? Where you put cash into labeled envelopes — rent, groceries, entertainment — and once the envelope is empty, you stop spending. Lucas: Exactly. That's a deliberate form of mental accounting that imposes self-control. Thaler also proposed the 'Save More Tomorrow' program, which lets people commit to increasing their savings rate when they get a raise — it's mental accounting that works with your brain instead of against it. Luna: So the key insight is that mental accounting isn't a bug — it's a feature of how we simplify financial decisions. But it can lead us astray when we let arbitrary categories override math. Lucas: Right. And one of the most powerful examples is the sunk cost fallacy, which is related. If you buy a ticket to a movie and then realize it's terrible, mental accounting says the movie is in your 'entertainment' budget, so you might stay to justify the cost. But the rational decision is to leave and do something you'd enjoy more. Luna: There's a great study from 1998 where people were given season tickets to a theater company. Half were randomly assigned to pay full price, half got a discount. The full-price attendees attended significantly more shows — even though the money was already spent in both cases. Lucas: Yes — because the mental account for the full-price ticket was larger, so skipping felt like a bigger loss. That's why companies love prepaid subscriptions. They know once you've paid, your mental accounting will push you to use the service to avoid 'wasting' that money — even if you'd rather do something else. Luna: And that extends to things like gym memberships. The classic statistic is that about sixty-seven percent of gym memberships go unused, but people keep paying because they mentally treat it as a commitment. Lucas: So mental accounting is everywhere. But here's the practical takeaway: you can hack your own mental accounts. For example, if you want to save more, create a separate account with a specific label — 'vacation fund' or 'new car fund' — and automate transfers into it. The label makes the money feel designated, which reduces the temptation to spend it. Luna: Similarly, you can use mental accounting to pay down debt. If you get a windfall, mentally assign it to 'debt repayment' before you even see it. That way you're less likely to treat it as fun money. Lucas: Which brings us back to the gift card example. If you receive a gift card, mentally reframe it as cash. Or better yet, sell it to a friend for ninety percent of its value — that forces you to treat it as actual currency. Luna: I've actually done that. I got a fifty-dollar gift card to a store I never shop at, and I swapped it with a coworker for forty-five dollars cash. It felt weird, but I ended up spending that cash on groceries — something I would have bought anyway. Lucas: Exactly — you broke the mental account label and made the money fungible again. That's a small win against your own bias. Luna: You know, I feel like every episode we do, we end up finding a way to think about something we already do in a new light. If walking through the economy with us has made something click for you — maybe you've started tracking your spending differently, or you've caught yourself in a mental accounting trap — that's exactly what we hope for. Lucas: And if you've gotten value from these conversations, a couple of dollars a month is genuinely what keeps these going. It's buy me a coffee dot com slash fexingo — no pressure, just a way for people who find the show useful to help it stay ad-free. Luna: Yeah, I think it's a nice way to keep the library lights on, so to speak. And we really mean it when we say every bit helps. Lucas: Alright — let's wrap up with one more practical trick. Thaler calls it 'the mental accounting of time.' If you have a free hour, you might mentally account it as 'free time' and waste it on social media. But if you label it 'writing time' or 'exercise time,' you're more likely to use it productively. Luna: So the same principle applies to time as to money. Interesting — I never thought about it that way. Lucas: Because the brain categorizes everything. The key is to be aware of the categories you're using, and to ask yourself: is this category helping me or hurting me? If it's hurting, rename it. Luna: That's a good rule of thumb. Thanks, Lucas. And for our listeners, next time you get a gift card or a bonus, try reframing it before you spend. Lucas: Exactly. And if you want to dig deeper into mental accounting, Richard Thaler's book 'Misbehaving' has an entire chapter on it. It's a great read. Luna: Alright, that's our show for today. We'll be back with another episode next week.