Our incredible shrinking brains

March 8, 2019

In his 1991 book Consciousness Explained, the cognitive scientist Daniel Dennett describes the juvenile sea squirt, which wanders through the sea looking for a rock to cling to. On finding one, it no longer needs its brain. So it . . . eats it.

Dennett’s example graphically illustrates the fact that brains are expensive in terms of energy. This is why most creatures on Earth get by without one, and even a creature with a brain like the juvenile sea squirt ditches it once it is no longer useful… Read article

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