Where does cognition come from? The most common claim is probably that cognition resides in the brain. But that can’t be enough. The idea of a bodiless brain is pretty disturbing – could a brain in a jar produce true cognition? The externalist (embodiment) philosophy maintains that the interaction among brain, body, and world is crucial; these three components together give rise to the mind, and no one is sufficient on its own.
The brain is the most obvious contributor to cognition. Neuroscience research is based in the idea that a better understanding of the brain will bring about a better understanding of thinking and behavior. Fuster demonstrates his belief in the primacy of the brain by claiming “our memories are networks of interconnected cortical neurons, formed by association, that contain our experiences in their connectional structure” (451). His use of the verb “to be” instead of phrases like “are created by” or “result from” exemplifies his commitment to the preeminence of the brain. Fuster explains complex cognitive phenomena in terms of their underlying brain events. For example, he describes working memory as a temporary activation of a network of perceptual and motor memories, or, more simply, as the product of neural events.
A number of researchers opposed to this brain-centered view advocate for the importance of the body in cognition. After all, every brain is situated in a body. Ballard emphasizes the vitality of the body. Specifically, he points out the central role that they eyes can play in a number of tasks requiring working memory. In one experiment, he showed participants a structure made of a number of different blocks. They had a resource area containing the same blocks they would need to duplicate the model, and were asked to do so in a separate workspace area. As they moved blocks from the resource area to the workspace area, participants looked back at the model much more than they should have if they had stored a representation of the model in working memory. In fact, the most common strategy was to look from the model, to the pick-up area, back to the model, and then to the drop area for each block. Thus, Ballard concludes, subjects used fixation as a deictic pointing device presumably because the computational costs of storing the model in memory (a cognitive task) were greater than the on-line costs of shifting their eyes. In sum, the paper provided a unique example of the connectedness of the physical body and the brain’s processes.
Just as brains are situated in bodies, bodies are situated in the world, so it is unsurprising that the world is likewise crucial for cognition. Spivey uses eye-movement experiments to demonstrate the role of the external visual environment in numerous types of cognition. In one especially persuasive experiment, participants listened to descriptions of spatiotemporally dynamic scenes while facing a large white screen. For example, they might hear a description of events unfolding in a skyscraper. Narration might start talking about an occurrence on a lower floor and continue describing events higher up sequentially. Even though subjects were looking at a blank screen, their eye movements corresponded with the direction of the description (in the case of the example, their eyes would shift upward with the description). Spivey argues that the physical eye movements are an integral part of language processing, and more broadly that physical movements enable many types of cognition.
Kirsh also presents numerous real-world examples of people’s use of their physical environments. Drawing from instances of people cooking, packing groceries at the supermarket, personal workshops and playrooms, and playing Tetris, he shows that the spatial arrangements we create in our own environments help simplify choices, perception, and computation. We simplify choices, for example, when we lay vegetables that need to be washed next to the sink because the proximity of the items makes the desired action (washing) more salient and undesired actions (like chopping) less salient. One way we simplify perception is by symbolically marking an object. He gives the example of a woman who, after measuring an amount of butter and cutting the stick in two, laid her knife on the measured piece to act as a sort of reminder. Finally, a Tetris game demonstrates our ability to use our environment to simplify computation. Approximately 800 to 1800ms after a zoid enters the screen, people display a burst of rotations, presumably because actually rotating the zoid takes less time than mentally rotating it. Thus, he concludes, humans use a variety of strategies to optimize their environments for cognition in many tasks.
Mind can emerge only when brain, body, and world come together. In this sense, “mind is best measured by its capabilities, not by its capacities” (Spivey, p. 183). Although the brain is undeniably an important contributor to thought and behavior, the physical presence of neurons and their connections does not alone constitute cognition. The bodies in which brains are found and the worlds in which the bodies are found are also crucial components of the human mind and cognition. Evidence from a variety of contexts has shown the importance of embodiment, or as Spivey concisely noted, “it might just be that your mind is bigger than your brain” (p. 162).