Mental accounting
People sort money into separate mental buckets and refuse to move it between them.
Money is treated as if it were labelled by source and purpose rather than as a single fungible pool. A person will hold low-yield savings for a holiday while carrying credit card debt, or spend a refund differently from an identical amount of salary. The buckets also set the reference points against which each gain and loss is coded.
How it shows up in software
Credits, points, and wallet balances all work because money inside them stops feeling like money. A user who would not spend twelve dollars will spend 1,200 credits. Budgeting products lean the other way, making the buckets explicit so people can plan with them. Expensing behaviour in B2B is the same mechanism: a line item inside an approved budget clears much faster than the same amount outside one.
Using it well
- In budgeting and finance tools, let users name their own categories rather than imposing a chart of accounts they do not think in.
- Show credit balances with the real currency equivalent nearby so users can reason about actual cost.
- Price B2B products against the budget line they will be charged to, since the comparison is to the tool being replaced, not to total spend.
- Separate one-off from recurring charges in billing summaries, because users already keep those accounts apart.
Where it turns manipulative
- Virtual currencies with awkward exchange rates and minimum top-ups exist to break the link to real money. Games regulators in several countries have examined exactly this, particularly where minors are involved.
- Splitting one price into base plus mandatory fees so each piece lands in a smaller mental account. That is drip pricing with extra steps.
- Framing a subscription as a daily amount while charging annually up front hides which account the money actually leaves.
Where you have seen it
YNAB
Every dollar of income has to be assigned to a named category before it can be spent from.
Steam
Wallet funds are added in fixed increments and then spent in-store, separating the top-up from the purchase.
Starling Bank
Spaces let users partition their balance into named pots inside a single account.
What the research says
- Thaler, 1985Mixed evidence
A framework showing how people segregate and integrate outcomes into accounts, predicting behaviour such as valuing an identical item differently depending on where it is bought.
- Kahneman and Tversky, 1984Mixed evidence
More people said they would buy a theatre ticket after losing an equivalent amount of cash than after losing the ticket itself, consistent with the ticket loss being charged to a theatre account.
- Hastings and Shapiro, 2013Well evidenced
When petrol prices fell, households shifted toward higher-grade fuel far more than an income effect of that size could explain, which is field evidence that a category budget is not treated as fungible with total wealth.
The lab vignettes are the weaker leg. The field evidence on category budgets and on how labelled transfers get spent is the stronger one, so cite that when the claim has to hold up.
Grades are a judgement about the evidence, not about how useful the idea is. Plenty of contested effects are still worth knowing, as long as you do not cite them as settled.