A. What Concepts Are, and What They are For

1. Concepts are ways of grouping things in the world so that we can predict and explain what goes on around us.
2. Humans have taken the cognitive niche, which means they have become "scientists". By learning the general principles about how things work, humans have come to exploit this knowledge to change the environment around them to suit their needs. This takes lots of intelligence, and the intelligence in question amounts to a human ability to solve problems abstractly.
3. To do this kind of "science", humans need to keep track of individuals and their properties. But some properties (like being something that starts with the letter 'j') are useless for science, while others are natural kinds , that is, properties (such as being a rabbit) that group the world in just the right way for us to draw useful inferences . So the problem that humans face is to come up with the right kind of properties, ones that provide useful information about the world.
4. The most useful categories should not be too wide (like: thing) since that provides very little to reason from, and not too narrow, (like: houses made of exactly 3,475 bricks) since it is hard to identify such characteristics. Pinker calls the efficient categories in the middle which we use every day such as rabbit, house, person, etc. base-level categories . Some natural kinds are base level categories, but not all of them are. For example the concept of being quark is a natural kind of sub atomic particle physics, but it is not a base-level category.

 

1. The Classical Account of Concepts . On the classical view, a concept is a symbolic structure defined both by its role in processing and by its definition in terms of other concepts. This is sometimes called the theory-theory of concepts. Concepts are like the terms of a scientific theory. (Consider the equation F=ma. What is mass? - The thing that plays a certain defined role in the theory of physics.) On the classical theory, inferences are drawn by applying rules or definitions. This brand of reasoning is performed not on the basis of similarities but instead on laws.
2. The Prototype Theory of Concepts : According to the prototype theory, a concept is not fixed by a definition but instead by a prototype, a typical member of the class. Membership in a category is fuzzy. Something is a member to the degree to which it resembles the prototype. Connectionist models a particularly well adapted to manage prototypes. A concept is a (fuzzy) region in a space of possible features, and the prototype is a point in that space. I illustrated this idea in class with a picture of the space for animals in a zoo. Inferences are drawn in prototype theory using the principle that things that are nearby in this space (similar) will have similar features. A problem with this kind of inference is that it can lead to stereotyping. An especially troublesome example of this problem is racial prejudice.
3. We never seem to be able to give the definition (rules) for any concept. Perhaps you think you can. For example, you might say that a tiger is a large, striped feline. But there are well known counterexamples to the definition: the albino tiger. It seems that what makes something a tiger is not the presence or absence of any one feature but something more like a cluster of features. The philosopher Wittgenstein expresses this idea using the term: family resemblance . In a famous passage, he asks us to try to define what a game is. It is very difficult to find any set of characteristics common to all games. Lakoff , has also argued that even concepts like mother and species which would seem to be strict, are in fact fuzzy. Pinker responds that even if this is true, the advantage of strict categories is that they idealize away from the fuzziness in the world and this is useful.
4. Elinor Rosch among others, has developed psychological evidence supporting prototype theory. (For example, 'A robin is a bird' is more quickly processed than 'a penguin is a bird'.) The definition approach does not explain our judgments of what is and is not typical.
5. Then again, concepts like 'is drunk' needn't be applied on the basis of similarity to a prototype, but via a process of inference based on rules. (This guy jumped in the pool with his clothes on. That's distorted judgement, and being drunk does that. Besides, he was at a party where there was a lot of drinking.So he's drunk.) Note that the inference did not rest on the guy's looking like a prototypical drunk. (He could have been immaculately dressed, etc..)

 

1. Pinker suggests that it may be a pointless question to ask whether a concept is learned or innate.
2. Most concepts are acquired through a combination of both learning and innate structure. The innate structure of the brain gives us a "head start" in learning by making it easier to learn the concepts we need. However, there are certain concepts that are so important to human functioning that they are very close to being entirely innate.

 

1. To what degree is the ability to perceive objects innate?
2. To answer this it helps to ask: What does the concept of an object involve? Here are some answers: Objects correspond to clusters of properties from different senses. Certain sights, sounds, tastes, etc. go together. We know the hidden parts are really there. Two objects can't be in the same place at the same time. Objects (generally) endure through time, and they tend to keep their properties (even if their apparent size or shape varies as the point of view varies).
3. In the past, the generally accepted view was that learning primarily explains how the child goes from a booming buzzing confusion in the perceptual world to a world of objects.
4. Recently cognitive scientists have discovered a new tool. Infant habituation (boredom) is used to tell us what the infant can and cannot distinguish. Surprise at novelty (versus "more of the same") can be measured by gaze, general posture, and by a sucking response.
5. In Elizabeth Spelke 's pioneering experiment, a donkey and a horse on adjacent screens were shown bouncing at different rates. A boing sound in sync with one but not the other was presented. Infants attend more to the screen where the boing is in sync, which suggests that infants have a conception of an object as a unity of sight and sound.
6. Spelke also showed 4 month old infants and image of a rod mowing back and forth but partly hidden by a rectangle. In one condition, the rectangle is removed to show a rod, and in the other one sees two rod fragments in coordinated motion (with a gap where the rectangle used to be). The first condition excited very little attention, but the second was highly attended to, suggesting that the discovery that there was no unified object was quite surprising.
7. Renee Baillargeon showed 5.5 month old infants a "drawbridge" apparatus. In the "possible" condition, the child sees the object and then the drawbridge occludes it and stops at the point where it would collide with the object. In the "impossible" condition, the bridge closes 180 degrees as if the object behind it weren't there. There was much more attention to the second condition.
8. Baillargeon also showed infants short and tall bunnies occluded by a u-shaped mask. The short bunny was too short to appear in the window (between the two legs of the u). and went from left to right behind the mask. The tall bunny was tall enough to appear in the window, but when it moved from left to right, it did not appear in the window. Infants attended much more to the tall bunny.
9. All of this suggests that very young infants already perceive a world of objects, and that learning has very little to do with it. Some of these experiments have been replicated with 1 or 2 day old infants.
10. Pinker notes that other concepts near the notion of an object, like gravity and inertia, are probably not innate.

 

1. An agent is something (like an animal or a human) that can move under its own power.
2. An ability to classify things into animate and inanimate categories is developed very early, and so likely innate. Infants become upset and surprised when a face stops moving, but not when a ball stops moving.
3. Even very young children can attribute goals to simple shapes that appear to move in ways that violate the laws of physics.

 

1. An essence of a thing is some principle in it that explains its form, growth, and ability to move or change. An essence is very much like one of Aristotle's forms.
2. In all cultures, the biological world is classified in terms of genus and species which correspond to something like different essences. These classification schemes work despite appearances that would suggested different groupings. (For example, tadpoles are classified with frogs even though they look like fish.)
3. Children show an appreciation for essences at an early age, suggesting that the concept of an essence is near innate. For example, young children know that changing the outward appearance of an animal does not change its expected biological properties. So painting a piglet to look like a cow will not cause it to grow up into something that says "Moo". They also know that changing the animal's "insides" does change what one should expect of its biological properties.

 

1. Artifacts are tools we construct to control our environment. (Look around, nearly everything you see is an artifact.)
2. Very young children understand that artifacts (even cars) are different from animals and other objects. They also fail to use essentialistic reasoning when it comes to artifacts. Changing a teapot to look like a birdhouse makes it into a birdhouse.
3. Children also understand that artifacts satisfy basic goals. They view the artifact in terms of what it is for. So regardless of appearance, they classify something as a chair, as long as it satisfies the purpose of a chair: to provide a surface for sitting.

 

1. One of the hardest things a child has to learn is how to understand other minds, that is, to be able to figure out what another person believes, desires, or intends.
2. Many cognitive scientists believe that there is a special brain module devoted to folk psychology. Its job is to allow us to predict behavior of others by understanding their mental states. Pinker refers to this as mind-reading.
3. Mind-reading skills are very difficult but they develop quickly, which provides some evidence that part of the brain is especially adapted to help us learn these skills.
4. Two month old infants can recognize eyes. By six months, they can tell when eyes are looking at them or not. By one year, they can tell what others are looking at.
5. By four years old, the (normal) child is able to solve the false belief task. When shown a pencil box that contains candy, they will no longer say that another child (whom they know did not see inside it) will think there is candy in the box; they will say instead that the child will think pencils are in there. This means they can tell the difference between their beliefs and the beliefs of others, so that they can correctly assign beliefs to others that are different from theirs - beliefs they know to be false.
6. It is widely believed now that the condition called autism is due the failure of a child's mind-reading abilities to develop properly. Autistic children behave as if people were just another kind of object. Autistics do not attend to faces, nor are they able to guess what people are thinking. They live isolated, asocial lives, although they may display strong intellectual gifts in other areas.