Consciousness: how ‘working memory’ may mysteriously give rise to it
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To solve a Rubrik’s cube, you need to engage your working memory.<br>T4W/Shutterstock
https://theconversation.com/consciousness-how-working-memory-may-mysteriously-give-rise-to-it-283823
https://theconversation.com/consciousness-how-working-memory-may-mysteriously-give-rise-to-it-283823
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You know that feeling when you walk into a room and immediately forget why you came in? Maybe you were there to fetch your keys. On your way to the room, you were thinking about grabbing your keys. But once you arrive, your keys have completely disappeared from your mind.
This is sometimes known as the doorway effect, since it often strikes when you walk into a new room. Why does it happen? The answer has a lot to do with a faculty called working memory. Information gets stored in working memory when we need it for the tasks that we are engaged in right now (like remembering to grab your keys).
What makes working memory so intriguing is its close link to consciousness. The doorway effect suggests that when information is removed from working memory, it immediately seems to leave consciousness. It also suggests that it is easy for information in working memory to be forgotten.
The link between working memory and consciousness is getting increasing attention in psychology, philosophy and neuroscience. Could working memory somehow give rise to consciousness? In my new book, I explore the complex relationship between the two.
Working memory: both rich and poor
To understand the doorway effect, we’ll need to know a bit about working memory. One thing that makes working memory so special is that it’s so rich, both in terms of the information it has access to, and its processing power. According to recent models of working memory, it can draw information from sensory channels (vision, touch, smell etc), as well as from other memory systems such as long-term memory and also the brain’s system for processing language. In other words, working memory is where a lot of the information in your brain comes together.
Wait, why am I carrying boxes?<br>Prostock-studio/Shutterstock
Once working memory has that information, there’s a lot it can do with it. Inside working memory are a host of different smaller systems for specific tasks, including visual and spatial reasoning (like solving a Rubik’s cube) and storing chunks of information (like a phone number). There’s even a “central executive” system (my favourite). The executive is like a merciless boss, assigning tasks to the different systems within working memory and keeping everything under control.
In other ways, what makes working memory so special is that it’s simultaneously very poor. Despite the riches of information available to it, working memory can only actually store a tiny amount of information at any one time.
In one classic experiment reported in 1997 people were asked to view a screen with several coloured shapes on it, which they were told to remember. The shapes then disappeared for about a second, and a new set of coloured shapes appeared. One of the new shapes might have changed colour. Participants were asked to spot whether there had been any changes between the two sets of shapes. This is called “change-detection”.
People were almost perfect at this when there were only 1-3 shapes involved in each set, but got steadily worse as the number of shapes was increased from 4-12. The experimenters argued that this is because it gets harder to store information as the number of shapes increases. This is because the capacity of working memory isn’t big enough to store lots of shapes. The experimenters concluded that the capacity of working memory is only about four “slots”. Once those slots are taken, working memory is full up: there’s simply no more room for any new information.
The idea that working memory has “slots” is closely related to something called “chunking”. Here are two strings of letters (nine in each). Try to memorise them both:
BBC FBI WWF
ZQK EWP WLJ
I bet you find the first string of letters easier to memorise. This is because they’re familiar, and so naturally your brain sorts them into three chunks. They can then be stored as three different chunks in working memory. For this reason, the first set only takes up three slots in working memory. The second string of letters is unfamiliar, and so requires us to store all nine letters as individual chunks. This is difficult because working memory quickly runs out of slots.
But like many features of working memory, its capacity is a hotly debated issue. A growing number of scientists have rejected the idea that it has “slots”, arguing instead that its capacity is more of a flexible resource that can be differently distributed across different pieces of information. According to...