A study that sampled people’s thoughts at random has identified four broad groups of thinkers and mapped the subjects that dominate everyday mental life. Economists behind the research collected more than 23,000 real‑time reports and found a steady flow of thoughts about work, food, sensory experience and, to a lesser extent, hobbies and relationships.
Method and scale
The research involved 258 volunteers aged 19 to 71 who downloaded an app that signalled them eight times a day for two weeks. At each prompt participants recorded their current thoughts, described what they were doing and rated their happiness. The approach — sampling thoughts in the moment rather than relying on retrospective recall — produced a high‑resolution picture of how mental content varies across the day.
“So much of what it means to be human is about what’s going on in our head,” said Dr Joshua Tasoff, a senior author on the study.
What people were thinking about
The analysis, which drew on the more than 23,000 responses, found that thoughts are shaped by daily rhythms: work‑related thinking predominates during daytime hours while entertainment and leisure dominate in the evening. The researchers observed that roughly half of reported thoughts were intentional, with the remainder described as intrusive or incidental — mind wandering, reminders or other non‑deliberate mental events.
- Sensory impressions — such as tiredness or sleepiness — and mental imagery together accounted for nearly a fifth of all thoughts.
- Work featured in about 17% of thoughts.
- Food and drink occupied roughly 14% of thoughts, with coffee especially prominent when people thought about wants.
- Hobbies, play and art made up about 10% of thoughts, a similar share to thoughts about relationships.
The study also identified four clusters or types of thinkers: those preoccupied with wider global concerns; those focused on household chores and finances; people concentrating on body and mind; and a group described as combining intense work focus with leisure pursuits. The authors note these categories are fluid — individuals may move between groups over time — but they provide a useful shorthand for patterns that emerge when sampling thoughts in the wild.
Context and implications
By sampling thoughts at random, the research adds a quantitative picture to questions about mental life that have traditionally been addressed with questionnaires or laboratory tasks. The prominence of sensory states and basic needs such as food underlines how much everyday cognition is grounded in bodily experience. The marked share of work‑related thought underlines how modern life shapes mental content across the day.
The findings also bear on debates about wellbeing. The study tested a long‑standing philosophical claim attributed to Marcus Aurelius that happiness depends on the quality of one’s thoughts, and it provides empirical texture to that idea by measuring what those thoughts actually are and how often they occur.
“The fact that we haven’t really looked at that as economists is really quite extraordinary,” said Dr Tasoff, reflecting on the novelty of treating thoughts as an empirical subject for economists.
| Topic | Approx. share of thoughts |
|---|---|
| Sensory impressions & mental imagery | ~20% |
| Work | ~17% |
| Food & drink | ~14% |
| Hobbies, play, art | ~10% |
| Relationships | ~10% |
The study’s methods and scale make it a useful reference point for researchers in psychology, behavioural economics and public health interested in linking momentary mental states to decisions, productivity and wellbeing. At the same time, the authors caution that the categories are descriptive rather than prescriptive: human thought is fluid, shaped by context, and not easily reduced to fixed types.
Overall, the research offers a rare, data‑rich window into what people actually think about across the day and suggests that simple, embodied concerns — how we feel, what we will eat, what we must do — occupy a substantial fraction of mental life.
