About 780,000 years ago, we humans started outsourcing one of our key bodily functions. That is to say, we discovered that using elements external to the body would get the job done more efficiently. So instead of laboriously doing the hard work of breaking down nutrients unaided, our ancestors began to help the job of digestion along – a job that had always, until then, been done internally and self-sufficiently – by cooking their food prior to eating it.

Hundreds of thousands of years later, some thinkers now claim that our use of smartphones and other tools plays a similar role in helping us to function. This time, however, it’s our cognition that we are outsourcing – to an extended mind. It’s argued that the process of cognition in cases like this is done collaboratively, in partnership, with the brain and the external tools both playing a crucial role. But is cognition comparable to digestion in this way? And does the extended mind hypothesis say anything really profound about the way that thinking sometimes happens, or is it simply a trivial truth about modern-day technology?

An unremarkable proposition

Nowadays, it’s true, most of us do use tools like calculators, satnav and predictive text to make things easier for our brains. (And before that, we used pens, paper, maps and books.) But is that really such a big deal?

Advocates of the extended mind would say that these non-biological props, the outside tools that help us to tot up a bill or find our way around, are actually acting as external parts of the cognitive system.

That sounds dramatic. But they’re not saying these items are minds in themselves, or that inanimate objects can carry out cognitive functions independently, without collaboration with a mind. And they’re not claiming that our technological tools are conscious.

Clark and Chalmers (1998), the original advocates of the extended mind, give the example of Otto, a man with Alzheimer’s, who writes down the facts he needs to remember in a notebook. That notebook, they contend, is part of Otto’s cognitive system; it functions in the same way a memory or belief would in a person without dementia. So, for example, Inga, who doesn’t have dementia, simply remembers the location of a museum she wants to visit. The only difference between cognitive processes for Inga and Otto is that Otto’s memory or belief about the museum’s location isn’t located within Otto’s brain, but in the notebook.

If that’s all that is being claimed, the postulation of an extended mind may be a rather unremarkable proposition, a simple stating of an obvious truth, albeit in radical-sounding terms. We might think of it as a question of terminology, rather than a departure from accepted views in any substantial way. The notebook could be described by extended mind advocates as part of a cognitive system, or by others as an external tool, and in either case its function is the same. But is there any more to the story?

Thinking beyond boundaries

Key to the rationale behind the extended mind hypothesis is the “parity principle”. This simply advocates an equity of approach, by stating that geography should not be a factor in labelling cognitive processes. Elements of cognition should be treated as such, wherever they happen to occur, inside or outside the brain or body.

So if, for example, the recall of a particular fact is typically thought of as a cognitive function when it takes place solely within the brain – as it does for Inga – then location should not be an issue. The parity principle states that the occurrence should still be accepted as a cognitive function, regardless, in Otto’s case, of its partial externality.

What are we to make of this? Location boundaries can certainly be useful. They offer a clear-cut, unambiguous, handy measure that can help us to differentiate how people or things should be treated. For example, we might think that saving a life, when the person is right in front of us, is morally imperative, while it would be only optional if the person were on another continent. Or we might say that in some cases ending a life is OK – as long as the subject is inside the womb rather than outside it.

But perhaps in reality, things are more fuzzy. Should location really matter that much, or is it just a convenient rule of thumb? Perhaps function is the most important thing. So, the breaking down of nutrients in food still happens, even if part of it is achieved by cooking food on a fire, rather than digestion within our bodies. And the recall of a restaurant’s location still happens, despite being helped along by words on a page, outside Otto’s brain.

Are minds a special case?

Perhaps we are inclined to resist the concept of an extended mind, because we think that our minds are special. Yes, we might accept that digestion can be helped along by external factors, just as vision can be aided by spectacles. But thinking? That’s a function that seems to be synonymous with “us”. It’s connected to consciousness, and creativity, and free will. We don’t want to admit any old inanimate object into the exclusive “cognition club”, because cognition seems to be at the very core of what it means to be a person.

If that’s the intuition, then I think the extended mind hypothesis is a useful exercise to help us gain clarity about exactly what cognition consists in.

Thinkers like N. Katherine Hayles, for example, have no problem with the idea that single-celled organisms and computational media both engage in a form of cognition. And with the rise of artificial intelligence, we might need to become more accustomed to the concept of non-biological “thinkers”, or agents that help us to carry out cognitive processes.

Meanwhile, neural prosthetics, such as cochlear implants for people with hearing impairments, are already here. Implanted in the body, they work in partnership with the brain to complete cognitive functions. Does their location in the body give them a pass, or does their alien, non-biological nature mean they can’t be counted as part of a cognitive system? As our technology develops, we’ll have a greater need to address these questions and achieve greater clarity about where cognition begins and ends.

Further reading

• Clark, A., & Chalmers, D. (1998). The Extended Mind. Analysis, 58(1), 7–19.
• Menary, R. (ed), (2010), The Extended Mind. MIT Press.

What do you think?

I’d love to know your opinions on the extended mind hypothesis. Add them in the comments below!