from:
http://www.beseenonabike.com/bsoab/beseenonabike_info_cyclist_perception.htm
To avoid an accident between a cyclist and a motorist the motorist must
first notice the cyclist. What makes cyclists get noticed by motorists?
Provided the driver is looking at the road ahead then surely the
cyclist will be noticed? Not necessarily! BeSeenOnABike claim that
drivers can suffer from two types of blindness: Inattentional Blindness
and Change Blindness.
Why is fluorescent clothing recommened when riding a bicycle during the
day? Why not wear bright clothes (white or yellow). Why wear bright
clothes at all - whats wrong with black clothes whilst cycling?
The strange phenomenum of Inattentional Blindness suggests that we may
not see something at all unless we are paying attention to it.
(Blackmore, 2005). Psychologists Arien Mack & Irvin Rock held subjects
attention by asking them to watch a fixation spot and, when a cross
briefly appeared, to decide whether the vertical arm was longer than
the horizontal arm. When a highly visible object unexpectantly flashed
close to the cross, most subjects failed to see it. Even more
surprising was that when they had to attend to a cross slightly to one
side of where they were looking, they failed to see the object flashed
right in front of their eyes. It seems that paying attention to one
side makes you blind where you are looking. Mack and Rock conclude that
there can be no conscious perception without attention.
In these studies, observers monitored one event while simultaneosly
ignoring another similar event. Observers monitored one team of players
passing a basketball while ignoring another team also passing a ball.
The observers were asked to count the number of times that the team
that was being monitored passed the ball. An Unexpected Event occurred.
For example, a woman carrying an open umbrella might walk across the
court. As in Mack & Rock's studies, observers often failed to see the
Unexpected Event.
View the movie.
http://viscog.beckman.uiuc.edu/grafs/demos/20.html
These studies demonstrate that attention is directed to objects and
events rather than spatial locations - the attended event was literally
superimposed on the unattended event, yet observers still did not see
the Unexpected Event.
BeSeenOnABike claim that in some accidents involving cyclists being hit
by motorists, the cyclist is the Unexpected Event. Because the motorist
suffers from Inattentional Blindness the motorist never sees the
cyclist! A cyclist wearing normal dark clothes may be not be visible to
a motorist (the cyclist is an Unexpected Event). By wearing bright
fluorescent clothing or other fluorescent gadgets rather than dark
clothes, the motorist attends to the cyclist - and sees him! Maybe a
fluorescent smiley could actually save lives!
What's the Difference between Looking and Seeing?
A large fraction of traffic accidents are of the type "driver looked
but failed to see". Here, drivers collide with pedestrians or cyclists
in plain view, with cars directly in front of them (the classic
"rear-ender"😉, and even run into trains. That's right - run into
trains, not the other way around!
In such cases, information from the world is entering the driver's
eyes. But at some point along the way this information is lost, causing
the driver to lose connection with reality. They are looking but they
are not seeing.
What's going on? Our findings indicate that the critical factor is
attention: To see an object change, it is necessary to attend to it.
To show this, Ronald Rensink developed a flicker paradigm in which an
original and a modified image continually alternate, one after the
other, with a brief blank field between the two. The onset of each
blank field swamps the local motion signals caused by a change,
short-circuiting the automatic system that normally draws attention to
its location. Without automatic control, attention is controlled
entirely by slower, higher-level mechanisms which search the scene,
object by object, until attention lands upon the object that is
changing. The change blindness induced under these conditions is a form
of invisibility: it can become very difficult to see a change that is
obvious once attended.
To see this effect for yourself, try out the following Change Blindness
examples.
BeSeenOnABike claim that in some accidents involving cyclists being hit
by motorists, the motorist suffers from Change Blindness. The motorist
never sees the cyclist! Maybe a cyclist wearing a fluorescent jacket
could actually saving their life by making the motorist attend to the
jacket and thus see the cyclist!
References
Inattentional Blindness (page 62) in Consciousness: A Very Short
Introduction by Susan Blackmore, Pub: Oxford University Press, 2005
Inattentional Blindness An Overview By Arien Mack & Irvin Rock
Overview of Inattentional Blindness (Visual Cognition lab)
Visual Cognition Lab demos
Tony Raven said:David Martin said:
Lesson 101: It doesn't matter what you are wearing if you are not where
people are looking.
Is the wrong answer. Human vision has evolved so that there is a very
small field of view that is good at interpreting visual information on
things you are looking at. Stare at the edge of a TV screen and try and
identify the face of the newsreader to see just how small it is.
However it is surrounded by a very large field visual system that is
good at identifying where the brain should swivel the eye to look.
Flashing lights are very good at getting the attention of that wide
field system and the flashing parameters to get noticed are different
from those that appear effective when looking directly at the source.
--
Tony
