(Image: Jules Clark/Getty)
Knowledge goes beyond memory, forming a rich and detailed understanding of your world. But you can know too much
One of the brain鈥檚 most useful features is the ability to absorb pieces of information and make connections between them. Knowledge really is power: a little can be a dangerous thing and the more you know the better equipped you are to deal with life.
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But what exactly is knowledge? How are facts stored, organised and recalled when needed?
Knowledge obviously relies on memory 鈥� in particular the type of memory that stores general information about objects, places, facts and people, known as semantic memory. This is the part of memory which knows that Paris is the capital of France, a constitutional republic in western Europe 鈥� but not the part which stores memories of a weekend break there.
Knowledge isn鈥檛 so much about what information you store as how you organise it to create a rich and detailed understanding of the world that connects everything you know.
The sight of a dog, for example, automatically activates other bits of information about dogs: how they look, smell, sound and move, the fact that they are domesticated wolves, the names of similar dogs you know, and your feelings about dogs.
How the brain achieves this gargantuan feat is far from clear. A recent proposal is that it has a 鈥渉ub鈥� which tags categories to everything we know and encounter, allowing us to connect related things.
In 2003, Tim Rogers, a cognitive psychologist now at the University of Wisconsin-Madison, proposed the anterior temporal lobe (ATL) as the hub (). The ATL is badly affected in people with semantic dementia, who progressively lose their knowledge of the meanings of words and objects but retain their skills and autobiographical memories. Experiments since then have backed this up 鈥� when the ATL is temporarily knocked out by a small electromagnetic pulse, people lose the ability to name objects and understand the meanings of words.
Rogers says that without this system we would spend a lot of time being confused about how things fit together. 鈥淗ow would you infer, for instance, that when making a collage with your kids, if you run out of sticky tape you can use the glue stick instead?鈥� he says. 鈥淭he tape is not similar to the glue stick in its shape, colour or how you use it. You need a representation that specifies similarity of kind.鈥�
The good news is that there seems to be no limit to the knowledge that can fit into a brain. As far as we know no one has ever run out of storage space.
鈥淭here seems to be no limit to the knowledge that can fit into a brain鈥�
But it seems you can know too much. Michael Ramscar at T眉bingen University in Germany reckons that anyone who lives long enough eventually hits that point just by virtue of a lifetime鈥檚 knowledge. He suggests that cognitive skills slow down with age not because the brain withers but because it is so full. And that 鈥� like an overused hard drive 鈥� takes longer to sift through.
Read more: 鈥�Mind expanding: 7 ways to fine-tune your brain鈥�
