There's a day each month when almost everyone in Portugal gets a little less sharp. It isn't marked on the calendar and it varies from person to person, but you recognise it well: it's the day your balance stops being a number and becomes a problem. The rent has already gone out, the loan instalment too, the supermarket shop hasn't yet — and every small decision ("do I order it now or wait?", "can this stretch to the end of the month?") starts taking up a disproportionate amount of space in your head.
For decades we treated this state as a matter of character: whoever struggles to reach month-end must be less disciplined, less organised, less capable. Behavioural economics research from the last decade says something else: financial strain doesn't reveal a weak mind — it produces a busy mind. And a busy mind decides worse.
Scarcity charges a tax — and it's paid in IQ points
In 2013, economist Sendhil Mullainathan and psychologist Eldar Shafir published Scarcity: Why Having Too Little Means So Much, the book that gave this field its name. Its central thesis: scarcity — of money, of time, of food — captures attention and consumes what they call mental bandwidth. In the book's own words: "Scarcity directly reduces bandwidth – not a person's inherent capacity, but how much of that capacity is currently available for use" [4].
That same year, with Anandi Mani and Jiaying Zhao, they took the thesis to the journal Science. In one of the experiments, simply asking people on low incomes to weigh up a hypothetical financial problem before reasoning tests was enough to sink their performance: worrying about money produced a cognitive drop equivalent to 13 IQ points — or a full night without sleep [1][2].
The most striking part of the study didn't need a laboratory. The researchers followed 464 sugarcane farmers in India, who receive at least 60% of their annual income in one go, at harvest time — which makes them "rich" after the harvest and "poor" before it. The same farmer, tested at both points, consistently scored better on tests of fluid intelligence after the harvest than before [1][2]. Same person, same intelligence. Different context.
The day-27 tunnel
Shafir, a professor of Psychology and Public Affairs at Princeton, describes the mechanism with a simple image: "When you focus heavily on one thing, there is just less mind to devote to other things. We call it tunneling — as you devote more and more to dealing with scarcity you have less and less for other things in your life, some of which are very important for dealing with scarcity" [3].
Jiaying Zhao, co-author of the Science study — at the time a researcher at Princeton, now at the University of British Columbia — sums up the cost: "These pressures create a salient concern in the mind and draw mental resources to the problem itself. That means we are unable to focus on other things in life that need our attention" [2]. Inside the tunnel there's room for tomorrow's rent and loan instalment. What's invariably left out are the decisions that would solve the next month-end: comparing insurance policies, renegotiating a contract, cancelling what you no longer use, saving whatever you can.
And this isn't a niche problem. According to Eurostat, in 2024 almost 1 in every 3 people in the European Union (30.0%) said they couldn't cope with an unexpected expense [5]. In Portugal, INE measured in 2025 that 28.7% of people live in households unable to pay an unexpected expense of €632 immediately, without resorting to a loan — a figure close to the monthly poverty line [6]. Almost a third of the population lives, by default, inside the tunnel.
From reacting to getting ahead
If scarcity consumes bandwidth, the right question isn't "how do I get more discipline?" — it's "how do I get attention and memory back into my head?". This is where an entire category of tools comes in: personal finance management apps. Their real value isn't in pretty charts; it's in outsourcing the vigilance. Every bill the tool watches on your behalf is one worry that stops running in the background of your mind.
There's a difference in kind between looking at your statement and looking at a projection. The statement tells you where the money's been. A projection tells you where it's going to be. The first feeds reaction — the day-27 scare, the juggling, the expensive credit decided inside the tunnel. The second enables getting ahead: seeing on day 5, with a clear head, the squeeze that would only hit on day 27 — and deciding with room to spare, not under pressure.
How AtivaMoney was designed for day 27
It was this problem — deciding under scarcity — that shaped part of AtivaMoney's design. We don't promise to stretch your income; we promise to give you back bandwidth:
- Balance projection (Cashflow): with what comes in, what goes out and when, you see today the likely balance at month-end. Day 27 stops being a surprise and becomes a calculation — made weeks in advance.
- Alerts that arrive before, not after: upcoming payments and out-of-pattern transactions are flagged — so you decide before the problem enters the tunnel.
- Categories and visibility: when every expense has context, the question "where did the money go?" — the one that eats up the most memory — is already answered by the time you need it.
- No conflict of interest: we live off your subscription, not your data or your credit. A tool that profited from your decisions under pressure wouldn't get you out of the tunnel.
Let's be honest about the limits: no app eliminates scarcity. If your income isn't enough, software can't stretch it — and some automatic-detection improvements are still on our roadmap. What a good tool does is reduce the cognitive tax of juggling: fewer things to remember, fewer scares, more decisions made outside the tunnel.
Five steps to get month-end out of your head
- Map your critical dates. Rent, loan instalments, subscriptions, salary: write down the day for each one. The "map of the month" turns diffuse anxiety into dated facts.
- Project your balance to month-end — today. Current balance, minus everything still to go out, plus what's still to come in. The number may not be pretty, but outside the tunnel it's better to decide with ugly numbers than with hope.
- Get ahead of the tunnel decisions. Decide on day 5, with a clear head, what you'd do if squeezed on day 27: what you'd cut first, what you'd never cut. Write it down. When the squeeze arrives, you won't spend bandwidth deciding.
- Automate the alerts, not the decisions. Alerts for payments and balance thresholds take the vigilance out of your head; the decision stays yours.
- Build in slack, even if minimal. A buffer of €30–50 already reduces the number of decisions made under pressure — and every decision avoided inside the tunnel is IQ recovered. With almost a third of people in Portugal having no margin for the unexpected [6], slack isn't a luxury: it's mental infrastructure.
The scarcity literature has a harsh but liberating message: you're not worse at managing money when it's short — you're paying a cognitive tax nobody told you existed. And that tax is reduced not by willpower, but by design: maps, projections, alerts, slack. Don't react to day 27. Get ahead of it.
References
- Mani, A., Mullainathan, S., Shafir, E. & Zhao, J. — Poverty Impedes Cognitive Function, Science, vol. 341, 2013
- Princeton University — Poor concentration: Poverty reduces brainpower needed for navigating other areas of life, agosto de 2013 (declarações de Jiaying Zhao e Eldar Shafir)
- American Psychological Association — The psychology of scarcity, Monitor on Psychology, fevereiro de 2014 (entrevista a Eldar Shafir)
- Mullainathan, S. & Shafir, E. — Scarcity: Why Having Too Little Means So Much, 2013; excerto em Behavioral Scientist
- Eurostat — Quality of life indicators — economic security and physical safety (dados de 2024)
- INE — Rendimento e Condições de Vida — 2025, destaque de 11 de dezembro de 2025
This article was translated from the Portuguese original.