A narrow category with a clear boundary and an agreed center, which is the recipe for a force that works.
Name a tool.
The first one that comes to mind. Type it.
Hammer. And this force has real evidence behind it.
Tool was among the ten categories in Rosch's typicality work, where 209 English speakers rated how good an example each item was. Hammer and saw sit at the center of the category; items like a ruler or a pencil sit at the edge and are slower to be accepted as tools at all.
Out of 0 answers so far. Free to quote, with the sample size beside it so a reader can judge the weight.
Once this passes 1000 answers, the measurement replaces the claim above as the headline of this page, and the claim becomes the thing being checked rather than the thing being reported. Saying that in advance is the point: a threshold decided afterwards is not a threshold.
The mechanism has a name and a literature. Eleanor Rosch showed in the 1970s that categories are not lists we search through — they have a center. Some members are better examples than others, people agree closely about which, and they answer measurably faster when the item is a good example. Her study collected 565 typicality ratings from 209 English speakers.
That is the whole of a psychological force. Ask somebody to answer quickly and you are not sampling the category at random — you are asking for whatever sits closest to its center. Speed is the instruction that does the forcing.
Compare the two categories. Animal stretches from insects to whales and includes the person being asked. Tool is narrow, has a clear boundary, and people agree closely about what sits at its center: something handheld, made of metal and wood, that does one obvious job by being swung or pulled.
A hammer is that description with nothing left over. A power drill is a tool by any definition and a worse example, because it introduces electricity. A ruler is a tool in name and rarely the one anybody reaches for.
Trade. Somebody who works with their hands answers from their own bench rather than from the cultural center, and their answer is likely to be more specific and less common. The prototype effect is strongest in people who have no particular expertise in the category, which is most of an audience and the reason the force works on stage.
If the results show a long tail of specific tools alongside a large hammer share, that is what it looks like: a general public answering from the middle, and a minority answering from experience.
The narrowness is the asset. Predict hammer, ask quickly, and expect a better rate than any of the broader categories in this study give. If a comparison across all eleven questions eventually shows tool and fruit leading, that is prototype theory doing exactly what it predicts.
Hammer is the expected answer, and it has real evidence behind it. Tool was one of the categories in Rosch's typicality work, with hammer and saw at the center.
The running count above tests whether that holds when people answer quickly rather than rate items.
Because the category is narrow, the boundary is clear, and people agree about what sits at the center — something handheld that does one obvious job.
Prototype effects are strongest in exactly those conditions, which is why tool is a better force than animal.
Less well. Somebody who uses tools daily answers from their own bench rather than the cultural center, and their answer tends to be more specific.
Prototype effects are strongest in people with no particular expertise in the category, which is most of an audience.
This is one of eleven questions in the full study, which asks for a card, a number, a vegetable, a fruit, an animal and more, and shows the running counts for all of them. The rest of the site is self-working card tricks you can play in the browser.