This unit considers two possible ways that intensions might be organized in our minds. It’s possible that some intensions are organized around sets of binary features (similar to phonetic features!) that divide up the world into clear categories. But binary features don’t leave room for exceptions. It’s also possible that our mind organizes word meanings around fuzzy categories, which have both prototypical members and peripheral members.
In the last unit, we saw that one important piece of a word’s meaning is the intension: the attributes or properties in your mind that you use to decide whether a thing in the world can be labelled with that word. In this unit, we’ll think about how those intensions might be organized in the mind.
One theory suggests that intensions might be organized in our minds as sets of binary features. So the intension for the word bird might be made up of features like [+living], [-mammal], [+wings], [+eggs], [+flying]. The intension for the word fish would have some features that are the same as the intension for bird, like [+living], [-mammal], [+eggs]. But the intension for fish would have [-wings] and [-flying]; instead, it would have [+swimming]. Some of these features could be shared across intensions for words that refer to quite different things in the world, so the intension for the word airplane, for example, probably includes [+wings] and [+flying], but [-alive].
The nice thing about using feature composition (also known as componential analysis) to represent intensions is that it can capture some of these similarities and differences across categories of things in the world using the simple, efficient mechanism of binary features. It may well be that our intensions for words describing the natural world are made up of some binary features. But can you think of any problems with this way of organizing meanings? Think about a penguin. A penguin is a member of the category of things that can be labelled with the word bird, and it shares some of the features of the intension for the word bird: it’s a living thing, it has wings, it lays eggs. But a penguin can’t fly. In fact, a penguin has the feature that’s associated with our intension for fish: it can swim. So it’s definitely a bird, but it definitely doesn’t have all the features associated with the intension for bird. If our intensions were organized in our minds just as binary features, then we wouldn’t be able to represent the meaning of the word penguin in our mind, but clearly, we do have an intension for the word penguin. So how might penguins be represented in our minds?
Another theory of intensions suggests that we have fuzzy categories in our minds. These categories contain exemplars, which are basically our memories of every time we’ve encountered an extension of the word. Some members of the category are prototypical exemplars: they have all the typical attributes of members of that category, so they’re near the center of the category. For most North Americans, a robin is about as prototypical as it gets as an exemplar of the category bird. Some exemplars are more peripheral: they have fewer of the defining attributes and they might have some attributes that aren’t typical. So a penguin, for example, is more peripheral because it doesn’t fly, and an ostrich is peripheral because it’s so darn big. Because the category has fuzzy boundaries, we might even have some exemplars in our mind that aren’t really members of the category at all, but share some attributes with category members, like bats: they’re small and they fly, but they’re not actually birds. In the next unit, we’ll talk about some of the evidence we have that our intensions might be organized in fuzzy categories with prototypes.