Background: The brains of all mammals have a unique layer of nerve cells covering the cerebrum. This layer is called the neocortex (the pink region of the brains in Figure above ). The neocortex plays an important role in many complex brain functions. In some mammals, such as rats, the neocortex is relatively smooth. In other mammals, especially humans, the neocortex has many folds. The folds increase the surface area of the neocortex. The larger this area is, the greater the mental abilities of an animal.

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Which brain belongs to the mouse, Brain A or Brain B?

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Which brain belongs to the gorilla, Brain A or Brain B?

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Will the mammal belonging to Brain A have greater or fewer mental abilities than the mammal belonging to Brain B?

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Will the mammal belonging to Brain B have greater or fewer mental abilities than the mammal belonging to Brain A?

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Is Brain A more or less likely to belong to the mouse than Brain B?

Situation: Matt is studying the brains of two different mammals. He knows that one brain belongs to a mouse and the other brain belongs to a gorilla, but is not sure which brain belongs to which mammal. To determine this, he observes the neocortex of each brain and finds that the neocortex of Brain A is relatively smooth and the neocortex of Brain B has many more folds.

Question: Is Brain A more or less likely to belong to the ape than Brain B?