Improve Your Communication Skills, 2nd Edition

• Bottom-up processing
: The brain doesn’t recognise 
objects directly. It looks for features, such as shape and 
colour. The networks that look for features operate 
independently of each other, and in parallel. ‘Bottom-
up’ processing occurs, appropriately, in the lower – and 
more primitive – parts of the brain, including the brain 
stem and the cerebellum. The neural networks in these 
regions send information upwards, into the higher 
regions of the brain: the neo-cortex.
• Top-down processing
: Meanwhile, the higher-level 
centres of the brain – in the neo-cortex, sitting above 
and around the lower parts of the brain – are doing 
‘top-down’ processing: providing the mental networks 
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8 Improve your Communication Skills
that organise information into patterns and give it 
meaning. As you read, for example, bottom-up 
processing recognises the shapes of letters; top-down 
processing provides the networks to combine the 
shapes into the patterns of recognisable words.
When the elements processed bottom-up have been matched 
against the patterns supplied by top-down processing, the brain 
has understood what’s out there.
Top-down and bottom-up processing engage in continuous, 
mutual feedback. It’s a kind of internal conversation within
the brain. Bottom-up processing constantly sends new 
information upwards so that the higher regions can update and 
adjust their neural networks. Meanwhile, top-down processing 
constantly organises incoming information into new or existing 
patterns.
The brain often has to make a calculated guess about what it 
has perceived. Incoming information is often garbled, 
ambiguous or incomplete. How can my brain distinguish your 
voice from all the other noise in a crowded room? Or a flower 
from a picture of a flower? How does it recognise a tune from just 
a few notes?
Top-down processing often completes incoming information 
by using pre-existing patterns. The brain creates a 
mental model:
a 
representation of reality, created by matching incomplete 
information to learned patterns in the brain.
Visual illusions demonstrate how the brain makes these 
calculated guesses. In the image in Figure 1.2, for example, we 
appear to see a white triangle, even though the image contains no 
triangle. The brain’s top-down processing completes the 
incoming information by imposing a ‘triangle’ pattern – its best 
guess of what is there. (The triangle is named after Gaetano 
Kanizsa, an Italian psychologist and artist, founder of the 
Institute of Psychology of Trieste.)
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