Sensation and Perception

Sensation “the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment” Basically, it’s the raw information from your environment Processed by sensory organs (eyes, ears, ect) and nerves in your body

“the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events” Basically, it is our interpretation of the raw information Influenced by experience, emotion, motivation and context

Bottom-up and Top-down processing Bottom-up processing starts at the sensory receptors and works up to our higher levels of processing Noticing the hue of someone’s face as being red, noticing the size of someone’s nose, the color of their eyes Top-down processing constructs perceptions from sensory inputs Identifying someone from their face, knowing a person was at the beach last weekend because they are sunburned

Selective Attention Selecting important stimuli from the many thousands acting upon us “important” is key here; texting seems important to your brain while driving, but it isn’t what’s REALLY important, is it?

Thresholds Absolute Threshold: minimum stimulation required for detection 50% of the time Difference Threshold: minimum difference a person can detect between two stimuli 50% of the time

PERCEPTUAL SET LOOK CLOSELY AT THIS IMAGE OF A SEAL TRAINER, TRAINING A SEAL TO BALANCE A BALL ON ITS NOSE GRIVAS – pg.124-125

PERCEPTUAL SET LOOK CLOSELY AT THIS IMAGE OF A MAN HOLDING HIS LADY’S HAND AS HE ENTERS THE COSTUME PARTY GRIVAS – pg.124-125

PERCEPTUAL SET Perceptual set = the predisposition or ‘readiness’ to perceive something in accordance with what we expect it to be GRIVAS – pg.125

PERCEPTUAL SET 5 factors influence perceptual set; Context Motivation Emotional State Past Experience Cultural Factors GRIVAS – pg.124-130

Refers to the setting or environment in which a perception is made PERCEPTUAL SET CONTEXT Refers to the setting or environment in which a perception is made GRIVAS – pg.127-128

PERCEPTUAL SET MOTIVATION Refers to the processes within us which activate behaviour that is directed towards achieving a particular goal GRIVAS – pg.129

PERCEPTUAL SET EMOTIONAL STATE How we are feeling can also influence the way in which we perceive visual information GRIVAS – pg.129

PERCEPTUAL SET PAST EXPERIENCE Refers to our personal experiences throughout our lives which leads to many individual differences in perception GRIVAS – pg.129-130

PERCEPTUAL SET CULTURAL FACTORS Experience with or in a particular culture can influence the way we process and interpret visual information GRIVAS – pg.130

DISTORTIONS OF VISUAL PERCEPTION BY ILLUSIONS VISUAL ILLUSION A misinterpretation (distortion or mistake) of real sensory information A mismatch between our perception and what we understand as reality GRIVAS – pg.133

DISTORTIONS OF VISUAL PERCEPTION BY ILLUSIONS GRIVAS – pg.133

“Fraser’s Spiral”

“The Disappearing Circle”

“The Disappearing Circle” When focusing on the black dot, why does the outer grey circle appear to fade away?

Sensory Adaptation Sensory Adaptation: Senses tuned to change; adaptable Responsive to increases and decreases of stimuli E.g.: Eyes adjust to darkness in a movie theatre Skin adapts to coldness of ocean water

What would happen if we did not have “sensory adaptation?” Can you think of other examples of how our senses adapt to changes in external stimuli? What would happen if we did not have “sensory adaptation?”

“The Stroop Effect” (Part A.)

“The Stroop Effect” (Part B.)

“The Stroop Effect” Why is it more difficult to name the colors in “Part B.?” The “Stroop Effect” illustrates how difficult it is to ignore some kinds of stimuli You were receiving two stimuli – the color and the word – which compete and slow you down when you try to name the color

THE MULLER-LYER ILLUSION A visual illusion in which one of two lines of equal length, each of which has opposite shaped ends, is incorrectly perceived as being longer than the other GRIVAS – pg.134-137

THE MULLER-LYER ILLUSION GRIVAS – pg.134-137 BEHAVIOURAL PERSPECTIVE

THE AMES ROOM ILLUSION A trapezium-shaped room that is longer and higher on one side than the other. The room’s unusual shape and being restricted to the use of monocular vision to view it provides the basis for the illusion. People in the room appear larger on the right than they do on the left GRIVAS – pg.138-140

THE AMES ROOM ILLUSION GRIVAS – pg.138-140