PSY270H1 Lecture Notes - Lecture 4: Change Blindness, Inattentional Blindness
Lecture 4:
How do we deploy attention:
Covert Attention: Shifting attention without focusing eyes on the target.
Attention is directed to a different region of space than the eyes.
Helmholtz (1894) provided empirical proof that we can covertly attend by holding his fixation
constant but moving his attention. He wrote letters on a wall and had a device which would
illuminate the room for a very brief displays (not enough time to move the eyes) and he found
that he could better attend to information he was attending to than the information he was
looking at.
Selection Theories: Bottleneck
Broadbent (1958): Proposed that we process multiple channels of information
-Different areas of the visual field
Sound originating from different areas of space
Different areas of touch, olfaction, etc.
Proposed that there is a filter that can be moved to block information from some channels while
allowing information from other channels to pass.
Creates a bottleneck (called this because it blocks information in the same way bottleneck blocks
passage of liquid, although this analogy is sort of crappy).
Selection Theories: Bottleneck:
Early Filter Theory: Goes through low level perception, to high level perception, through
semantic processing (meaning), and finally to conscious awareness (where you have conscious
access to the information).
So according to the early filter theory we only have low level perception of information we
aren’t attending to but once we start attending to something it goes through all the processing
(visual on slide).
The ate filter theory differs in that it says that the information you aren’t attending to doesn’t
make it to conscious awareness BUT does go through all the other levels of processing (Visual
on slide).
Dichotic Listening Tasks; where is the filter?
Dichotic Listening: A technique in which different streams of auditory information are played to
each ear using headphones.
Attention is manipulated by asking subjects to ‘shadow” the content presented to one ear.
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