Perception & Cell Assemblies

Learned Aspects Of Perception

Whilst the Gestalt laws play an important role in perception, it is believed that there is also a learned aspect of perception.

For example, if you listen to some music which is unfamiliar to you and completely different from what you have heard before, the song may appear to have little or no pattern it. However the more you listen, the more you will begin to notice the patterns it contains.

Therefore whilst the Gestalt laws allowed you to recognise some pattern with the song to begin with, the fact that you are able to detect more patterns within the song the more you listen to it, shows that there is also some learned aspect to perception.

If you listen to the audio clip below until about 1min 30secs, you should be able to get some idea of this learned aspect of perception.

What you may have noticed is that at the start of the song portions of it seemed to make sense. By that I mean you were able to recognise some form of pattern within the song.

That form of recognition can be attributed to the Gestalt laws, which suggest that there is some form of inbuilt pattern recognition we all possess.

However the first time you heard the chorus, it probably sounded like a bunch of incoherent nonsense. But the second or third time you heard it, you probably recognised it as a pattern within the song and it seemed to fit within it. This would be attributed to the learnt aspect of perception.

Cell Assemblies

One way to explain why repeated exposures to something enhances our perception of it, is in terms of the neuronal activity that exposure causes in our brain.

For example, research done by psychologist Donald Hebb suggests that when our neurons repeatedly fire in response to a stimulus, they form a “cell assembly”.

This is defined by Hebb as a group of neurons that the brain uses over and over again to create a representation of an external pattern.

If a particular pattern is very complex, then a particular cell assembly may only represent a portion of that pattern.

Therefore by grouping individual cell assemblies together (something Hebb called a “phase sequence”) we are able to perceive a larger pattern.

So to break this down, what Hebb is proposing is that when you are exposed to some sort of a pattern (such as in music) there are certain groups of neurons which fire in the brain. If you are exposed to this pattern again, the same group of neurons (a cell assembly) will fire again.

If you are exposed to a new and more complex pattern, this cell assembly may only fit with a part of the new pattern. As a result, only a portion of this new pattern will seem to make sense to you, seem right, or seem like it fits.

As you hear this pattern again, new cell assemblies will be formed representing different parts of it.

Eventually, there will come a point when you are exposed to that complex pattern that it makes sense to you and you can recognise the individual patterns within it.

This is a result of all your cell assemblies (which are relevant to that pattern) working together in a phase sequence which forms the whole pattern.

This is why you can hear a completely unfamiliar piece of music, yet still recognise certain portions of it. According to Hebb, this is due to the presence of an established cell assembly which is firing.