Why human memory is not a bit like a computer’s

My latest 3QD essay is about the mystery of human memory, and why it is not at all like computer memory. I discuss the quirks of human memory formation and recall, and the concept of “content-addressable memory”.

3quarksdaily: Why human memory is not a bit like a computer’s

Here is an excerpt:

Decades of experience with electronics has led many people to think of memory as a matter of placing digital files in memory slots. It then seems natural to wonder about storage and deletion, capacity in bytes, and whether we can download information into the brain ‘directly’, as in the Matrix movies.

The computer metaphor may seem cutting edge, but its essence may be as old as civilization it is the latest iteration of the “inscription metaphor”. Plato, for example, described memory in terms of impressions on wax-tablets — the hard drives of the era. According to the inscription metaphor, when we remember something, we etch a representation of it in a physical medium — like carvings on rock or ink on paper. Each memory is then understood as a discrete entity with a specific location in space. In the case of human beings, this space is between the ears. Some memory researchers even use the term “engram” to refer to the neural counterpart of a specific memory, further reifying the engraving metaphor.

Before getting to the problems with the inscription metaphor, I should say that at a sufficiently fuzzy level of abstraction, it is not entirely useless. There is plenty of neuroscientific evidence that memories are tied to particular brain regions; damage to these regions can weaken or eliminate specific memories. So the general concepts of physical storage and localizability are the least controversial aspect of the inscription metaphor (at least at first glance).

The issue with the inscription metaphor is that it leaves out the aspects of human memory that are arguably the most interesting and mysterious — how we acquire memories and how we evoke them. When we look more closely at how humans form and recall memories, we may even find that the storage and localizability ideas need to be revised.

Read the whole piece here:

3quarksdaily: Why human memory is not a bit like a computer’s

 

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Is the mind a machine?

My latest 3QD essay explores the “mind as machine” metaphor, and metaphors in general.

Putting the “cog” in “cognitive”: on the “mind as machine” metaphor

Here’s an excerpt:

People who study the mind and brain often confront the limits of metaphor. In the essay ‘Brain Metaphor and Brain Theory‘, the vision scientist John Daugman draws our attention to the fact that thinkers throughout history have used the latest material technology as a model for the mind and body. In the Katha Upanishad (which Daugman doesn’t mention), the body is a chariot and the mind is the reins. For the pre-Socratic Greeks, hydraulic metaphors for the psyche were popular: imbalances in the four humors produced particular moods and dispositions. By the 18th and 19th centuries, mechanical metaphors predominated in western thinking: the mind worked like clockwork. The machine metaphor has remained with us in some form or the other since the industrial revolution: for many contemporary scientists and philosophers, the only debate seems to be about what sort of machine the mind really is. Is it an electrical circuit? A cybernetic feedback device? A computing machine that manipulates abstract symbols? Some thinkers so convinced that the mind is a computer that they invite us to abandon the notion that the idea is a metaphor. Daugman quotes the cogntive scientist Zenon Pylyshyn, who claimed that “there is no reason why computation ought to be treated merely as a metaphor for cognition, as opposed to the literal nature of cognition”.

Daugman reacts to this Whiggish attitude with a confession of incredulity that many of us can relate to: “who among us finds any recognizable strand of their personhood or of their experience of others and of the world and its passions, to be significantly illuminated by, or distilled in, the metaphor of computation?.” He concludes his essay with the suggestion that “[w]e should remember than the enthusiastically embraced metaphors of each “new era” can become, like their predecessors, as much the prisonhouse of thought as they at first appeared to represent its liberation.”

Read the rest at 3 Quarks Daily:

Putting the “cog” in “cognitive”: on the “mind as machine” metaphor

Ways of Knowing

Here is an excerpt from my latest 3QD essay:

“To attempt an understanding of understanding, I think it might make sense to situate our verbal forms of knowledge-generation in the wider world of knowing: a world that includes the forms that we share with animals and even plants. To this end, I’ve come up with a taxonomy of understanding, which, for reasons that should become apparent eventually, I will organize in a ring. At the very outset I must stress that in humans these ways of knowing are very rarely employed in isolation. Moreover, they are not fixed faculties: they influence each other and gradually modify each other. Finally, I must stress that this ‘systematization’ is a work in progress. With these caveats in mind, I’d like to treat each of the ways of knowing in order, starting at the bottom and working my way around in a clockwise direction.”

Read the rest at 3 Quarks Daily: Ways of Knowing

(I’ve collected links to all my 3QD essays here.)