Apr 092011

Eleanor RoschAs many of you must have realised, the poll in my last post was inspired by the psychologist Eleanor Rosch. Back in the 1970’s she ran a series of experiments getting people to rate how prototypical of a category particular words were.

Here’s the start of some instructions from one of her experiments:

Think of dogs. You all have some notion of what a “real dog,” a “doggy dog” is. To me a Retriever or a German Shepherd is a very doggy dog while a Pekinese is a less doggy dog. Notice that this kind of judgment has nothing to do with how well you like the thing… You may prefer to own a Pekinese without thinking that it is the breed that best represents what people mean by dogginess. In this study you are asked to judge how good an example of a category various instances of the category are.

So in my poll I gave you pictures of a German Shepherd (Dog 1) and a Pekinese (Dog 2) and nobody chose the Pekinese as ‘the-doggiest’. Tony made me laugh by suggesting it was for dusting the furniture!  

Dog 1                                                                                     Dog 2

But several people chose the German Shepherd and Cat pointed out that it’s closest to a wolf which is a sort of dog prototype. It sounds like Clarissa was tempted to vote for the German Shepherd as well because it was brown, and it could well be that brown is a prototypical colour for dogs. Result: Eleanor Rosch is bang on target.

Dog 3

The third dog I stuck in the poll was a mut. Several people mentioned how hard it was to choose between Dog 1 and Dog 3. I think being a mix of many kinds of dogs is what eventually won dog 3 ‘the-doggiest-dog’ vote in the poll.  More on Dog 3 in a minute.

So what did Eleanor Rosch find out?  Here are some more examples from her experiments.  In a lot of them people had fifteen, twenty or fifty words to rank in a category, but to keep life simple, I’ll just give you three and it’s a little puzzle. You have to work out how well the words represent the category on the left. Are they good representations, so-so or a bit dodgy? (There’s one of each). I’ll post the answers in the ‘Comments’.

Furniture lamp, chair, telephone
Fruit orange, papaya, olive
Vehicle surf board, tractor, automobile
Weapon gun, shoes, whip
Vegetable bean, pea, peanut
Carpenters tools saw, wedge, scissors
Sport ice skating, cards, football
Toys fire engine, books, doll
Clothing stockings, pants (BrE trousers), bracelet
Bird robin, penguin, raven

The most striking thing about Eleanor Rosch’s research was how consistent the answers were. Time and again items would come up in the same or similar position in the list. She concluded that the more an item has attributes in common with other members of the category, the more it will be considered a good and representative member of the category.

However, she also found that the people she was experimenting on had persistent illusions about how the categories were working:

Subjects, upon receiving feedback from the experiment, and audiences, upon being told of it, generally argue that they feel positive that there are many attributes common to all members of the category even when they cannot think of any specific attributes for which there are not counterexamples.

So it seems we want to believe that there are necessary and sufficient conditions that apply to all members in a category, when in practice, as Wittgenstein has pointed out,  there aren’t. I think this worth remembering when we’re teaching. Students may be looking for clear cut meaning boundaries which don’t exist in practice. Maybe some little puzzles along the lines of the one above might help them with that?

I’m sure I’ve read somewhere that the word rankings varied across cultures. So American respondents thought a robin was the birdiest-bird, but when other researchers replicated the experiments in the UK, it was sparrows. We can expect those category boundaries to shift a bit across borders and cultures. No surprises there, I guess.

A very big thank you to everyone who took part in the poll. I’d love to hear any more thoughts on this, so please put them in the comments. I’m going to put the answers from the Eleanor Rosch research there too – click the red ‘Comments’ link at the bottom of this post to check them out.

The other thing I should explain is that we have a new addition to our family. His name is Carter and he is the mut in picture 3. His vocabulary is tiny compared to Chaser’s but he attracts a surprising number of  ‘What a wonderful dog!’ comments on walks when he’s not misbehaving – which he does all too often. I’ve been putting it down to Americans being more liberal with compliments (they’re commonly used as an invitation to talk here) but you’ve just helped explain it to me. It’s not that he’s a wonderful dog so much as a wonderful example of the prototype of  ‘dog’. Ha!


Rosch, E. Cognitive representation of semantic categories. Journal of Experimental Psychology: General, 1975, 104, 192-233

Rosch, E & Mervis C. Family resemblances: studies in the internal structure of categories. Cognitive Psychology, 1975, 7, 573-605

 Posted by at 10:24 pm

  6 Responses to “Categories and prototypes”

  1. Answers Most prototypical – So-so – Very low down the list
    Furniture chair – lamp – telephone
    Fruit orange – papaya – olive
    Vehicle automobile – tractor – surf board
    Weapon gun – whip – shoes
    Vegetable pea – bean – peanut
    Carpenters tools saw – wedge – scissors
    Sport football – ice skating – cards
    Toys doll – fire engine – books
    Clothing pants (BrE trousers) – stockings – bracelet
    Bird robin – raven – penguin

  2. Note that the European Robin is Erithacus rubecula, whereas the American Robin is Turdus migratorius, so this is a really unfortunate example. The birds are not even closely related, as they belong to different families: Muscicapidae (Old-World flycatchers) and Turdidae (thrushes) within the order Passeriformes (songbirds).

  3. Well I never, John! Thanks so much for stopping by, and chipping in. So if I understand you correctly, the word ‘robin’ is applied to two very different species on each side of the pond. Wow! I had no idea! Well that would explain the discrepancy!

    Growing up in the UK, the sparrow always seemed to be the ‘commonest’ bird so it seems perfectly logical that we’d think of it as prototypical there. But I’ve become aware that bird life is very different here – for example there are things called chicken-hawks and turkey-buzzards, which have left this Brit scratching her head and wondering whether American birds simply don’t care what they copulate with.

    Can you expand and tell us more?

  4. Furniture chair, lamp, telephone
    Fruit orange, papaya, olive
    Vehicle automobile, tractor, surf board,
    Weapon gun, whip, shoes,
    Vegetable pea, bean, peanut
    Carpenters tools saw, wedge, scissors
    Sport football, ice skating, cards
    Toys doll, fire engine, books,
    Clothing pants (BrE trousers), stockings, bracelet
    Bird robin, penguin, raven

    This had me asking various type-defining questions. Do carpenters make tables with scissors? Can you rob a bank with shoes? Would a person only wearing bracelets be dressed?
    Very interesting!

    As for Americans stopping you to talk when you have a dog, I noticed this too when I was dog-sitting Stateside once. However, if you have a baby, no-one bothers you. In the UK, on the other hand, you can’t walk 5 yards without being accosted if you’re pushing a pram.

  5. […] while ago in a comment here, John Cowan explained that the word ‘robin’ is used to describe two entirely different […]

  6. […] while ago in a comment here, John Cowan explained that the word ‘robin’ is used to describe two entirely different […]

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