Change blindness is a cognitive phenomenon where individuals fail to notice significant changes in their visual environment, often due to focused attention and limited cognitive resources. Studies have shown that this inability to detect change is influenced by factors such as expectations, attention, age, and distractions. The implications of change blindness extend to various real-world scenarios, including social interactions, driving, eyewitness testimony, and air traffic control.

1. Change Blindness
(Cognitive Psychology -2)
Ref-About.com
by
Col Mukteshwar Prasad(Retd),
Mtech(IIT Delhi)
,CE(I),FIE(I),FIETE,FISLE,FInstOD,AMCSI
Contact -+919007224278,
e-mail -muktesh_prasad@yahoo.co.in
for book ”Decoding Services Selection Board” and
SSB guidance and training at Shivnandani Edu and
Defence Academy,Kolkata,India

2. Change Blindness
 What Is Change Blindness?
 If something in your visual field changed dramatically right before your eyes,
you would notice it immediately, right?
 While you might think that you see or are aware of all the changes
that happen in front of you, the reality is that there is simply too
much information for your brain to fully process and be aware of
every single thing that happens in your immediate environment.
 In many cases, big shifts can happen in your visual field and you are never
even aware of these changes. Psychologists refer to this as change
blindness.
 What is it?
 Why exactly does it happen?
 What effect does it have on how you perceive and interact with the world
around you?

3. Defining Change Blindness
 "The term 'change blindness' refers to the surprising difficulty
observers have in noticing large changes to visual scenes."
(Simons & Rensink, 2005)
 "Change blindness is a failure to detect that an object has moved or
disappeared and is the opposite of change detection. The phenomenon
of change blindness can be demonstrated even when the change in question
is large. For example, Simons and Levin (1998) carried out studies in which
participants started to have a conversation with a stranger. This stranger was
then replaced by a different stranger during a brief interruption (e.g., a large
object coming between them). Many participants simply did not realize that
their conversational partner had changed!"
(Eysenck & Keane, 2005)

4. Research on Change Blindness
 Blackmore, Belstaff, Nelson, and Troscianko (1995) - In this experiment,
participants were shown an image that was changed during a brief blank
interval in the visual scene. The researchers found that when there is a brief
break in the visual scene, people find it more difficult to detect changes.
 Simons and Levin (1998) - In this experiment, researchers engaged
participants in a conversation. Then, during a period of distraction, they
switched the original person for someone else. Surprisingly, only about half of
the participants noticed the swap.
 O’Regan, Rensink, & Clarke (1999) - Researchers found that when small
shapes are splattered over an image, such as mud splashes over a car
windshield, large changes can be made to a visual scene without the
observer noticing. While previous research demonstrated that change
blindness could be produced by a visual disruption such as flickering,
blinking, or eye movement, this study demonstrated that change blindness
can also occur without visual masking.
 Levin et al. (2000) – When researchers told observers about changes that happened
in a film sequence and showed them stills from the film, 83 percent of the participants
predicted that they would notice these changes. When these observers did not know

5. Research on Change Blindness
 Feil & Mestre (2010) - Recent research also suggests that subject-matter
experts may be more adept at noticing change in their area of expertise than
novices. For example, a physicist would be better able to detect changes to a
physics problem than a college student taking his first physics course.

6. Why does Change Blindness Occur?
 The ability to detect change plays a major role in our daily life. A couple of
examples include noticing when a car drifts into our lane of traffic or
observing a person entering a room. If perceiving change is so important,
why do we often fail to notice major changes?
 There are a number of factors that play a role:
 Focused Attention and Limited Resources
 At this very moment, your attention is focused on the words you are reading.
While you are looking this sentence, are you giving any attention to the wall
color of the room you are in or to where your feet are placed?
 Until asked that question, it's highly unlikely that you were paying attention to
either of those things.
 According to researcher Daniel Simons, attention is limited, so we have to
pick and choose what we focus on. We can really only focus on one
thing at any given time, so it is that one thing that we pay attention to in
great detail. As a result, large volumes of information in the world
around us simply pass by our awareness because we lack the
resources to attend to it.

7. Why does Change Blindness Occur?
 Expectations and Past Experiences
 "One reason people think they would see the changes may be that they
know from past experiences that changes that occur in real life are
usually easy to see. But there is an important difference between changes
that occur in real life and those that occur in change detection experiments.
Changes that occur in real life are often accompanied by motion, which
provides a cue that indicates a change is occurring."
(Goldstein, Sensation and Perception, 2010)
 We don't notice some changes, particularly the artificially induced ones in
an experimental lab, because we simply don't expect such changes to
occur.
 How often in real life does one person suddenly turn into somebody
else?
 When would an object suddenly blink into existence when it wasn't
there before?
 Would a person's shirt really change color right before our eyes?
 Because these things simply don't occur in our day to day existence,
we tend not to notice them when they happen in an staged

8. Why does Change Blindness Occur?
 Other Factors That Play a Role
 A number of factors can also influence change blindness, including
 attention,
 age,
 how objects are presented, and
 the use of psychoactive drugs.
 Researchers have found that shifting a person's attention, such as causing a
distraction, leads to increased change blindness. Studies have found that older
people are less likely to detect changes in a visual scene.
 Our ability to take in visual information is constrained by limited resources. "The
basic problem is that far more information lands on your eyes than you can
possibly analyze and still end up with a reasonable sized brain," explained
researcher Jeremy Wolfe of Harvard Medical School to The New York Times.
 To cope with this overwhelming amount of data, huge amounts of information enter
our visual system without being assimilated.
 Focused attention on a particular part of our environment allows us to essentially
shine a spotlight on something that we deem as important that needs to be
processed and attended to.

9. Change Blindness in real World
 Detecting change plays a major role in our ability to function in our daily life.
Some of these include:
 Social Interactions: Change blindness can impact our day-to-day social
interactions such as relatively minor slip ups like asking the wrong waiter for
the check
 Driving: Failure to detect changes in the environment while you are driving
can lead to dire, sometimes fatal, consequences. Researchers have found
that distractions such as talking on the phone or texting can impact
attention and lead to increased change blindness.
 Eyewitness Testimony: Researchers have found that change blindness can
also play a role in a witnesses ability to recount the details of a crime or to
identify the perpetrator of a crime.
 Air Traffic Control: If an air traffic control fails to detect important changes,
fatal accidents could result.

10. References
 References
 Angier, N. (2008, April 1). Blind to change, even as it stares us in the face. The New York Times. Retrieved from
http://www.nytimes.com/2008/04/01/science/01angi.html
 Davies G, Hine S.(2007). Change blindness and eyewitness testimony. The Journal of Psychology 141(4), 423-434.
 Eysenck, M. W. & Keane, M. T. (2005). Cognitive psychology: A student's handbook. New York:
Psychology Press Ltd.
 Goldstein, E. B. (2010). Sensation and perception. Belmont, CA: Wadsworth.
 O'Regan, J. K., Rensink, R. A., & Clark, J. L. (1999) Change-blindness as a result of “mudsplashes”. Nature. doi:10.1038/17953
 Simons, D. J. & Rensink, R. A. (2005) Change blindness: Past, present, and future. Trends in Cognitive Sciences,
9(1), 16-20.