This is the least predictable of the classic forces, and the reason is interesting: the category has two centers rather than one.
Name an animal.
The first one that comes to mind. Type it.
Performers disagree here, which is itself the finding. Some expect dog, some expect lion, and both are defensible for different reasons.
Rosch's typicality work covered bird rather than animal, and found robin at the center and penguin at the edge. Animal is a broader category than bird, and breadth is exactly what makes it a weaker force.
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.
Ask for an animal and two different questions get answered.
Some people answer the everyday category and say dog — the animal actually in their life, familiar to the point of invisibility. Others answer the archetypal category and say lion or elephant — the animal from the picture book, the one that means animal in a way a spaniel somehow does not.
A category with two centers is a poor force. Where the fruit question has one strong answer and a thin tail, this one splits its weight, and a performer betting on either side is betting on which sense of the word the person reached for.
Rosch's prototype effects are strongest in categories with clear boundaries and a shared center. Animal has neither: it stretches from insects to whales, it includes the person asking the question, and the everyday sense of the word rules out most of what it technically covers.
Compare it with tool or fruit, where the boundary is clear and the center agreed. The narrower the category, the more reliable the force — which is why performers asking this question usually narrow it: name a zoo animal, name a pet.
Whether the top answer takes a commanding share or the leaders sit close together. Two answers within a few points of each other would confirm the two-center reading, and would tell a performer to narrow the question rather than trust the folklore.
Performers disagree, which is the interesting part. Some expect dog, the animal actually in people's lives; others expect lion, the animal that means "animal" in a picture book.
The running count above shows whether the answers split, which would explain why this force is less reliable than the others.
Because the category is broad and has two competing centers. It stretches from insects to whales, and the everyday sense of the word rules out most of what it technically covers.
Prototype effects are strongest where the boundary is clear and people agree about the center.
By narrowing the category. Asking for a zoo animal, a farm animal, or a pet removes the ambiguity that splits the answers.
A narrower category has a more agreed center, and a more agreed center is a better bet.
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.