How many minds are we talking about?

Let's set a range: everyone within 100 metres of you. That's a circle of about 0.03 km². In a dense city like Madrid, with roughly 5,000+ residents per km², that's around 170 people, before you count offices, shops and the metro. Step into a packed train or stadium and the number jumps into the thousands.

A dense European city neighbourhood seen from a rooftop in the morning
In a dense neighbourhood, about 170 people live within 100 metres of you.

Your day, hour by hour

Here's roughly how the 24 hours might go, using what researchers know about how minds actually work.

  • The noise. Hundreds of overlapping inner voices: alarms, commutes, emails, worries about the day.
  • Mostly daydreams. A Harvard study found people's minds wander about 47% of the time they're awake. Most of what you hear isn't secrets; it's drifting.
  • The lies. Diary studies by psychologist Bella DePaulo found people tell about one or two lies a day, mostly small social ones. You'd hear each one, and the thought behind it.
  • Learning to filter. Your brain already picks one voice out of a noisy room (the cocktail party effect). You might learn to focus on one mind at a time.
  • Silence. As people fall asleep, thoughts fade into dreams. After 24 hours, quiet would feel priceless.

How fast do thoughts move?

In 2020, researchers at Queen's University in Canada used brain scans to detect the moment one thought ends and another begins, which they called "thought worms". Their estimate: about 6,200 thought transitions per day for a typical person. Multiply that by 170 people and you're receiving over a million thought switches in a single day.

Of course, this is a thought experiment: nobody knows what a "heard" thought would sound like. Much of thinking isn't neat words but images, feelings and half-sentences.

Long-exposure night photograph of a city interchange with tangled streams of car light trails
Thousands of thought switches per person, every day.

The social cost

Hearing every unfiltered reaction from friends, partners and colleagues could be brutal, even when those thoughts mean nothing. People often have passing thoughts that don't reflect what they truly believe or would ever act on. Without the filter of speech, you'd have no way to tell a fleeting thought from a real opinion.

That's why many people say they wouldn't want this power permanently: privacy of thought is part of what lets relationships work.

Two coffee cups and a small plate on a café table by a sunny window
You'd hear every small social lie, and what people really meant.

What would save you

Your brain is already excellent at ignoring. In 1953, Colin Cherry described the cocktail party effect: in a crowded room you can follow one conversation and tune out the rest, yet still notice when someone says your name. With practice, that same skill might let you focus on one mind at a time, and finally get some peace.

A calm lake at night under a sky full of stars
By midnight, silence would feel priceless.

FAQ

How many thoughts does a person have per day?

A 2020 study estimated about 6,200 thought transitions per day. Popular claims of 60,000 thoughts a day aren't based on solid research.

How often does the mind wander?

In a large experience-sampling study (Killingsworth & Gilbert, 2010), people's minds were wandering about 47% of the time.

What is the cocktail party effect?

The brain's ability to focus on one voice in a noisy environment while filtering out others, first described by Colin Cherry in 1953.

How often do people lie?

Diary studies by Bella DePaulo and colleagues (1996) found people told about one to two lies per day on average, mostly minor social lies.

Sources & further reading

  • Killingsworth, M. A. & Gilbert, D. T. (2010). A wandering mind is an unhappy mind. Science.
  • Tseng, J. & Poppenk, J. (2020). Brain meta-state transitions demarcate thoughts across task contexts exposing the mental noise of trait neuroticism. Nature Communications.
  • DePaulo, B. M. et al. (1996). Lying in everyday life. Journal of Personality and Social Psychology.
  • Cherry, E. C. (1953). Some experiments on the recognition of speech, with one and with two ears. Journal of the Acoustical Society of America.
  • Madrid city population density: Spanish National Statistics Institute (INE).

This is a hypothetical scenario explained with real science. Numbers are rounded for clarity. Images are AI-generated illustrations of real phenomena. Spotted an error? Tell us and we'll fix it.