Modified PowerPoint from: Aneeq Ahmad -- Henderson State University. Worth Publishers © 2007

Restored Vision

After cataract surgery

blind adults were able to

regain sight. These

individuals could

differentiate figure and

ground relationship

however had difficulty

discriminating a circle and

a triangle (Von Senden,

1932).

Facial Recognition

After blind adults were

able to regain sight they

were unable to recognize

faces, they would only

recognize individual,

distinct features.

Normal observers also

show difficulty in facial

recognition when lower

half of the pictures are

changed.

Courtesy of Richard

LeGrand

Sensory Deprivation

Kittens raised without

exposure to horizontal

lines later had

difficulty perceiving

horizontal bars.

Suggests that vision

is at least partly an

acquired senseBlakemore & Cooper

(1970)

Perceptual Adaptation

Visual ability to adjust to an

artificially displaced visual

field, e.g., prism glasses.

(think about the “drunk

googles” you used in

driving school)

We (humans) can even

adapt to an upside down

world!

Courtesy of Hubert

Dolezal

Perceptual Set

Time flies I cant they're too fast

Perceptual Set

Time flies. I cant they're too fast.

Perceptual Set

A mental predisposition to perceive one thing

and not another. What you see in the center

picture is influenced by flanking pictures.

From Shepard,

1990.

(a) Nessie or a tree trunk? (b) Flying Saucers or Clouds??

Perceptual Set

Usually our perceptual sets lead us to fairly

accurate conclusions…yet sometimes they can

lead us astray…

Frank Searle, photo Adams/ Corbis-Sygma

Dick

Ruhl

Children's schemas represent reality as well as their

abilities to represent what they see.

Schemas develop through experience!!

SchemasSchemas are concepts that organize and

interpret unfamiliar information.

Courtesy of Anna Elizabeth

Voskuil

Context Effects

A given stimulus can evoke radically different

perceptions, based on the immediate context of

the stimulus.

To an East African the sitting woman is balancing a metal

box on her head and the family was sitting under a tree.

Cultural Context

Context instilled by culture also alter perception.

Perception Revisited

Is perception innate or acquired?

Perception & Human Factors

Human factors psychologists design machines

that assist our natural perceptions.

The knobs for the stove burners on the right is easier to

understand than one on the left.

Photodisc/

Punchstock

Courtesy of General

Electric

Human Factors & Misperceptions

Understanding human factors can enable us in

designing equipment that can avoid disaster.

Two-thirds of airline crashes are due to human error.

Largely based on errors of perception.

Does Extrasensory Perception

exist?

Perception without sensory input is called

extrasensory perception (ESP).

What do you think???

A large percentage of scientists do not believe in

ESP.

Claims of ESP

Paranormal

phenomena include

claims of astrological

predictions, psychic

healing,

communication with

the dead and out-of-

body experience, but

the most relevant are

telepathy,

clairvoyance and

precognition.

Claims of ESP

1.Telepathy: Mind-to mind communication. One

person sending thoughts and the other receiving it.

2.Clairvoyance: Perception of remote events. Like

sensing a friend’s house on fire.

3.Precognition: Perceiving future events. Such as a

political leader’s death.

4.Psychokinesis: Performing a physical task with

your mind.

Premonitions or Pretensions?

Can psychics see the future? Can psychics aid

police in identifying locations of dead bodies?

What about psychic predictions of the famous

Nostradamus?

The answers to these questions are NO!

Nostradamus’ predictions are “retrofitted” to

events that took place afterwards…a psychic has

not predicted surprising events in history like 9-11

or Princess Diana’s death.

Putting ESP to Experimental Test

In an experiment with 28,000

individuals, Wiseman tested

psychically influencing or

predicting a coin toss.

People were able to correctly

influence or predict a coin

toss 49.8% of the time.

Scientists cannot validate

the claims of ESP…because

they can not replicate the

instances of the supposed

abilities in lab conditions!!!

Why do people continue to

believe? Because they

WANT to or because they

know someone who thinks

they have experienced ESP.