Car accidents and plane crashes:
How theories of space-based and
object-based attention can be a matter
of life and death
Evidence for Spatial Attention
Eriksen & Eriksen (1974): - The Flanker Compatibility Effect
Task: to read the centre letter of a five letter string and push the lever one way if the letter
was “H” or “K” and the other way if the centre letter was “S”
Reaction times are quicker if the letters flanking the middle letter are compatible
Resp. Compatible Resp. Incompatible
KKHKK SSHSS
RTs < RTs
But this only works when the flankers are very near to the target (<1˚).
The theory of a minimum width spotlight of attention has evolved from this evidence.
Other evidence for spatial attention came from studies which showed that attention fell off with
increasing eccentricity:
Hoffman & Nelson (1981)
Identify a target and a secondary shape nearby
As distance increased between the target and the secondary shape, accuracy was reduced.
Downing and Pinker (1985)
used a cueing experiment with 10 potential target sites:
X
Reaction times slowed as the invalid cues appeared further away from the cued location.
, A RGUMENTS FOR OBJECT - BASED ATTENTION ARISE
Kahneman & Henik (1981):
Occlusion of objects renders them visually incomplete and fragmented in the raw retinal
image.
Yet we perceive a coherent world and perceive complete objects rather than parts of
objects.
Therefore we must have some form of early visual mechanism which can construct
representations of objects.
Rock & Gutman (1981):
Asked subjects to identify just one of two pictures which were superimposed upon each
other.
Subjects were asked to give an aesthetic judgement on one of the coloured pictures and to
ignore the other
Subjects couldn't remember the unattended images.
Therefore attention is object-based as otherwise the unreported object would have also
been processed within the beam of attention.
Driver & Bayliss (1989), Bayliss & Driver (1992):
Eriksen & Eriksen (1974) found response compatibility effects for distracters that were close
together (<1˚).
But spatial separation between a distracter and a central target may decrease the effect of
the distracter due to the breakdown of the target/distracter perceptual group.
They did two experiments (1989, 1992) using the Flanker Compatibility Effect to distinguish
spatial attention and object-based attention.
S K H K S vs. SKHKS
Driver & Bayliss (1989)
S K H K S vs. SKHK S
Bayliss & Driver (1992)
Egly, Driver and Rafal (1994)
Within-object invalid targets were responded to faster than between-object invalid
targets.
How theories of space-based and
object-based attention can be a matter
of life and death
Evidence for Spatial Attention
Eriksen & Eriksen (1974): - The Flanker Compatibility Effect
Task: to read the centre letter of a five letter string and push the lever one way if the letter
was “H” or “K” and the other way if the centre letter was “S”
Reaction times are quicker if the letters flanking the middle letter are compatible
Resp. Compatible Resp. Incompatible
KKHKK SSHSS
RTs < RTs
But this only works when the flankers are very near to the target (<1˚).
The theory of a minimum width spotlight of attention has evolved from this evidence.
Other evidence for spatial attention came from studies which showed that attention fell off with
increasing eccentricity:
Hoffman & Nelson (1981)
Identify a target and a secondary shape nearby
As distance increased between the target and the secondary shape, accuracy was reduced.
Downing and Pinker (1985)
used a cueing experiment with 10 potential target sites:
X
Reaction times slowed as the invalid cues appeared further away from the cued location.
, A RGUMENTS FOR OBJECT - BASED ATTENTION ARISE
Kahneman & Henik (1981):
Occlusion of objects renders them visually incomplete and fragmented in the raw retinal
image.
Yet we perceive a coherent world and perceive complete objects rather than parts of
objects.
Therefore we must have some form of early visual mechanism which can construct
representations of objects.
Rock & Gutman (1981):
Asked subjects to identify just one of two pictures which were superimposed upon each
other.
Subjects were asked to give an aesthetic judgement on one of the coloured pictures and to
ignore the other
Subjects couldn't remember the unattended images.
Therefore attention is object-based as otherwise the unreported object would have also
been processed within the beam of attention.
Driver & Bayliss (1989), Bayliss & Driver (1992):
Eriksen & Eriksen (1974) found response compatibility effects for distracters that were close
together (<1˚).
But spatial separation between a distracter and a central target may decrease the effect of
the distracter due to the breakdown of the target/distracter perceptual group.
They did two experiments (1989, 1992) using the Flanker Compatibility Effect to distinguish
spatial attention and object-based attention.
S K H K S vs. SKHKS
Driver & Bayliss (1989)
S K H K S vs. SKHK S
Bayliss & Driver (1992)
Egly, Driver and Rafal (1994)
Within-object invalid targets were responded to faster than between-object invalid
targets.
