University Of Education Lahore, Vehari Campus
Assignment
Cognitive Psychology
Topic
Process of Perception
Submitted to
Dr. Asif Shehzad
Submitted by
Lubna Zafar
Roll No
Msf23003273
Class
M.PHIL Education 2nd semester morning
Date
May 8, 2024
WHAT IS PERCEPTION?
While our sensory receptors are constantly collecting information from the
environment, it is ultimately how we interpret that information that affects how we
interact with the world. Perception refers to the way sensory information is organized,
interpreted, and consciously experienced.
Perception involves both bottom-up and top-down processing. Bottom-up
processing refers to the fact that perceptions are built from sensory input. On the other
hand, how we interpret those sensations is influenced by our available knowledge, our
experiences, and our thoughts. This is called top-down processing.
Although our perceptions are built from sensations, not all sensations result in
perception. In fact, we often don’t perceive stimuli that remain relatively constant
over prolonged periods of time. This is known as sensory adaptation. Imagine
entering a classroom with an old analog clock. Upon first entering the room, you can
hear the ticking of the clock; as you begin to engage in conversation with classmates
or listen to your professor greet the class, you are no longer aware of the ticking.
The clock is still ticking, and that information is still affecting sensory
receptors of the auditory system. The fact that you no longer perceive the sound
demonstrates sensory adaptation and shows that while closely associated, sensation
and perception are different.
Attention and Perception
There is another factor that affects sensation and
perception: attention. Attention plays a significant role in determining what is sensed
versus what is perceived. Imagine you are at a party full of music, chatter, and
laughter.
You get involved in an interesting conversation with
a friend, and you tune out all the background noise. If someone interrupted you to ask
what song had just finished playing, you would probably be unable to answer that
question.
One of the most interesting demonstrations of how
important attention is in determining our perception of the environment occurred in a
famous study conducted by Daniel Simons and Christopher Chabris (1999). In this
study, participants watched a video of people dressed in black and white passing
basketballs.
Participants were asked to count the number of times
the team in white passed the ball. During the video, a person dressed in a black gorilla
costume walks among the two teams. You would think that someone would notice the
gorilla, right? Nearly half of the people who watched the video didn’t notice the
gorilla at all, despite the fact that he was clearly visible for nine seconds. Because
participants were so focused on the number of times the white team was passing the
ball, they completely tuned out other visual information. Failure to notice something
that is completely visible because of a lack of attention is called inattentional
blindness.
Motivations, Expectations, and Perception
Motivation can also affect perception. Have you ever been expecting a
really important phone call and, while taking a shower, you think you hear the phone
ringing, only to discover that it is not? If so, then you have experienced how
motivation to detect a meaningful stimulus can shift our ability to discriminate
between a true sensory stimulus and background noise.
The ability to identify a stimulus when it is embedded in a distracting
background is called signal detection theory. This might also explain why a mother is
awakened by a quiet murmur from her baby but not by other sounds that occur while
she is asleep. Signal detection theory has practical applications, such as increasing air
traffic controller accuracy. Controllers need to be able to detect planes among many
signals (blips) that appear on the radar screen and follow those planes as they move
through the sky.
In fact, the original work of the researcher who developed signal
detection theory was focused on improving the sensitivity of air traffic controllers to
plane blips (Swets, 1964).
Our perceptions can also be affected by our beliefs,
values, prejudices, expectations, and life experiences. As you will see later in this
module, individuals who are deprived of the experience of binocular vision during
critical periods of development have trouble perceiving depth (Fawcett, Wang, &
Birch, 2005).
The shared experiences of people within a given
cultural context can have pronounced effects on perception. For example, Marshall
Segall, Donald Campbell, and Melville Herskovits (1963) published the results of a
multinational study in which they demonstrated that individuals from Western
cultures were more prone to experience certain types of visual illusions than
individuals from non-Western cultures, and vice versa.
One such illusion that Westerners were more likely to
experience was the Müller-Lyer illusion. The lines appear to be different lengths, but
they are actually the same length.
