Читать книгу Figure It Out - Stephen P. Anderson - Страница 22

To reconcile these two views, let’s turn to the cognitive philosopher Andy Clark, who has proposed two opposing models of human thought.¹⁷ One model, based on the computational theory, equates the mind with the brain and puts cognition—every last bit of it—in the head. Clark calls this the brain-bound model. If this model is correct, it means that the body exists exclusively for sensory perception (i.e., information inputs), with motor movements (i.e., action outputs) playing no role in cognition itself. It also means that cognition depends entirely on neural activity. If that’s the case, we should, in theory, be able to pop the top off a human skull, scoop out the brain, dump it into a cognition tank hooked up to ocular and auditory processors and say, “Voila, there it is, a thinking, intelligent, conscious being.”¹⁸

When you read an article about the mind that features an image of the brain, you’re probably dealing with the brainbound model. It is the culturally dominant conception of the mind, one exemplified by the computer scientist and futurist Ray Kurzweil. Kurzweil envisioned a day when our brains could be uploaded to the cloud, and we would exist as conscious creatures made of pure information.¹⁹ While this view has many proponents, it’s worth noting that even neuroscience has been coming around to the idea that what the brain does is intimately connected to the messy reality of our biology. The neuroscientist Alan Jasanoff summed up the “fundamental lesson of neuroscience” this way: “The brain cannot be all there is.”²⁰ The more science learns, the more questions arise about the brainbound model.

Because of this, Clark proposed an alternative model called the extended mind.²¹ In this model, neural processes don’t handle each and every cognitive task. Some will happen in the head, while others might happen in the world. The basis for this idea is that we evolved in a physical world, which also means we evolved cognitive tooling that relies on our brains and our bodies and anything in the world. Sometimes that means thinking happens entirely in the head with mental representations. Other times it means the cognitive act depends on information outside the head—external representations—and interactions with other worldly resources. When the mind is extended, to use Clark’s vivid wordage, “Cognition leaks out into the world.”²²

We can draw a line between these two models (see Figure 2.3). On one side is brainbound, with mind and brain co-located in the skull and the body serving only as input and output. On the other side is extended, with cognition spread across brain, body, and anything in the world: whiteboards, smartphones, sticky notes, maps, notebooks, and even other people. The extended model doesn’t dismiss what the brain does. But neither is it biased toward electrical signals whizzing through squishy gray tissue.

FIGURE 2.3 Contrasting models of human cognition. Brainbound locates all of cognition in the brain. Extended spreads it across brain, body, and the world.

A key difference between these two models is how much they depend on neurons. Brainbound assumes neuronal hegemony: thinking is restricted to what neurons do. Extended argues for neural frugality: thinking can happen with neurons, but it doesn’t have to. Sometimes our thinking happens outside the head because it can be faster, or easier, or just plain better to do the work out there.²³ This isn’t the brain being lazy. Instead, it’s more like the busy executive who effectively delegates certain tasks to the people around her rather than doing all the work herself.