Have you ever wondered why you usually miss
glaring bloopers in major motion pictures? If
you are like most people, you probably believe
that just because your eyes are open, you are
seeing. So why do we sometimes fail to see
things that are right in front of our eyes?
The reality is that attention plays a major role
in visual perception. One of the primary
reasons why you fail to notice these mistakes
in films and television programs is a
psychological phenomenon known as
inattentional blindness. When your attention is
focused on one demanding task, such as
paying attention to the main character in a
movie, you might not notice unexpected things
entering your visual field.
Research on Inattentional Blindness
The term was first coined by psychologists
Arien Mack and Irvin Rock who observed the
phenomenon during their perception and
attention experiments. "Because this inability
to perceive, this sighted blindness, seemed to
be caused by the fact that subjects were not
attending to the stimulus but instead were
attending to something else ... we labeled this
phenomenon inattentional blindness (IB),"
they explained.
One of the best-known experiments
demonstrating inattentional blindness is the
Simons and Chabris "invisible gorilla test." In
this experiment, researchers asked participants
to watch a video of people tossing a
basketball and the observers were told to
count the number of passes or to keep track of
the number of throws versus bounce passes.
Afterwards, the participants were asked if they
had noticed anything unusual while watching
the video. In most of the tests, approximately
50 percent of the participants reported seeing
nothing out of the ordinary.
What was it they had missed? In some
instances, a woman dressed in a gorilla suit
strolled through the scene, turned to the
camera, thumped her chest and walked away.
How on earth could so many people could
miss such an obvious and unexpected thing
right before their eyes? Because their
attention was focused elsewhere on a
demanding task, the gorilla basically became
invisible.
Explanations for Inattentional Blindness
Why does inattentional blindness occur?
Rather than focusing on every tiny detail in
the world around us, we tend to concentrate
on things that are important and then rely on
our existing schemas to fill in the rest. This is
highly economical and allows us to focus our
existing attentional, cognitive, and processing
resources on the things that are most
important, while still allowing us to have a
cohesive and seamless experience of the world
around us.
One of the reasons why people so often miss
the gorilla sauntering through a scene of
people playing basketball is simply because
the stimulus lacks what is known as
ecological validity. How often does a gorilla
show up in the middle of a basketball game?
Because this is unlikely to happen in a real-
world setting, we are simply less likely to
notice it.
The salience of the stimuli is important. While
we do sometimes fail to miss essential
information in the world around us, we are
generally pretty good at noticing relevant
information such as a car speeding toward us
or a deer jumping out of the trees into the
road.
A Few Real-World Examples of Inattentional
Blindness
Even though you think you are paying
attention to the road, you fail to notice a
car swerve into your lane of traffic, resulting
in a traffic accident.
You are watching a historical film set in
ancient Greece. You don't notice a major
blooper in which an airplane appears in the
background of a pivotal scene.
You decide to make a phone call while
driving through busy traffic. You fail to
notice that the traffic light has turned red,
so you run the stop light and end up
getting a traffic ticket for inattentive
driving.
While playing a video game, you are so
intently focused on spotting a specific type
of "bad guy" that you miss another threat
to your character and you end up losing the
game.
Observations
"Simons and Chabis carried out a further
experiment in which observers counted the
passes made by members of the team
dressed in white or the one dressed in
black. The gorilla's presence was detected
by only 42% of observers when the attended
team was the one dressed in white, thus
replicating the previous findings. However,
the gorilla's presence was detected by 83%
of observers when the attended team was
the one dressed in black. This shows the
impact of similarity between the unexpected
stimulus (gorilla) and task-relevant stimuli
(members of the attended team)."
(Eysenck & Keane, 2011)
"Inattentional blindness can be attributed
to an overuse of top-down processing .
Information that participants were not
attending to was filled in with that
individual's expectations. In this sense,
inattentional blindness is similar to change
blindness . However, change blindness
generally refers to missing a change in a
previously present stimulus, and
inattentional blindness generally refers to
missing a new stimulus."
(Mauldin, K., 2013)
The bottom line:
Just because your eyes are open doesn't
mean you are seeing everything in the world
around you. Perception depends upon
numerous factors, including attention.
Sometimes we miss the things that are right
in front of us.
References
Eysenck, M. W. & Keane, M. T. (2011).
Cognitive psychology: A student's handbook .
Psychology Press.
Mack, A. & Rock, I. (1999). Inattentional
blindness: An overview by Arien Mack and
Irvin Rock. Retrieved from www.theassc.org/
files/assc/2417.pdf
Mauldin, K. (2013). Inattentional blindness. In
A. K. Taylor (Ed.). Encyclopedia of human
memory. Santa Barbara, CA: ABC-CLIO, LLC.
Simons, D. J., & Chabris, C. F. (1999).
Gorillas in our midst: Sustained inattentional
blindness for dynamic events. Perception, 28,
1059-1074.
Simons, D. (2012, Sept.). But did you see the
gorilla? The problem with inattentional
blindness. Smithsonian Magazine. Retrieved
from http://www.smithsonianmag.com/
science-nature/but-did-you-see-the-gorilla-
the-problem-with-inattentional-
blindness-17339778/?no-ist

Source: http://psychology.about.com/od/cognitivepsychology/fl/What-Is-Inattentional-Blindness.htm

Excellent post. I learned about this some semesters ago.

I'm glad you included the source as well as the references. Good job.
Many people post articles and refuse to give credit to whom credit is due.