Sensation and Perception Unit 2 Flashcards
Sensation
Process by which information in the psychical world is detected by sensory organs
Eyes, ears, nose/mouth, skin (somesthetic senses, temp and pain, vestibular: balance, kinesthetic: location of body in space, muscles/joints)
Perception
Process by which sensory information is interpreted in the brain
Seeing and hearing, the way it is understood happens in the brain
What process does sensation begin with ?
Transduction- all sensory organs are responsible for transduction
What do transducers do
Almost translation machines, they translate energy
Taking in vast amounts of information in the environment, it exists as various forms of energy, (ex. When you taste things/ smell things, its chemical energy)
Brain doesn’t understand any of this, the transducers translates all these various types of energy into electrical energy (action potential)
When you taste things/ smell things, its chemical energy
Challenge and solution during sensation
Challenge- Sensory organs can transduce the avalanche of sensations available in the environment, but the brian cannot process all of this information
Solution- Restrict information through selection and selective attention
Challenge with attention
Extremely limited
What do we pay attention to
Physically salient - bright, loud, sharp, taste bad
Appealing or interesting (attractive, curious)
Personal meaning or importance (ex. cocktail party effect)- Your name, your attention switches
Things that allow you to achieve your goals
Yarbus 1967
found eye tracking shows that people look toward aspects of the painting that will provide the information needed to meet their goals (the instruction)
Goals impact attention and therefore what we perceive
When we focus our attention on one specific place, we will miss some stimuli
Sensory information is not always sent to the brain for processing even when you think you’ve seen everything
Yarbus vs the gorilla
Gorilla is in the middle of it all, straight through field of vision 50% of people did not see it, the information passed through visual receptors but was not comprehend
Demonstrates how attention can narrow to include only things that are relevant to our goals
Simons and Chabris 1999
white team passing basketball, did you see the gorilla?
Inattentional blindness
ail to see elements of a scene you are watching (objects, actions)
Happens for two reasons
Focused on a goal
What you saw was Unexpected
Change blindness
Fail to see gradual change to elements of a scene you are watching
Chabris, Weinberger, Fontarine and Simmons (1999)
Count the number of times the runner in front of you touches their hat, while a staged fight went down
Interested in how many people would report haven seen this altercation
Ran it at night time- How many saw the fight: 33%
Daylight- How many people saw the fight: 60%
Take home message: It is possible to “see” (ie. sense) something without “seeing” (ie. perceiving)
Unanswered question- Do expert searchers’ experience inattentional blindness?
Drew, Vo, and Wolfe (2013)
Had radiologist who were trained to find cancer on scans, to see if they could find a hidden gorilla in the scan (was 50x larger than cancer in brain)
83% of the radiologists did NOT see the gorilla
With eye goggles, 80% of the 83% of people looked straight at it
Take home-
Even experts experience inattentional blindness
Confirmed in 2022 meta-analysis
How is information from the senses combined during perception?
Brain doesn’t deal with information coming from one sense at a time; it combines information from all senses; (In previous studies^ only one was used (visual))
This is multimodal integration
Multimodal integration
Playing sports: an amazing baseball catch
Visual system, tracking the ball, surroundings, kinesthetic, vestibular
Playing music: Reading music while playing
Speech: couldn’t understand people during covid bc couldn’t see mouth
Why do we see similarities in perception across people?
Similarities due to transduction -Human transducers work in the same way for most people, yielding a similar perceptual experience.
Similarities due to experience - We often use similar perceptual rules to interpret stimuli and consequently have similar perceptual experiences
Shape constancy
Brightness constancy
Why do we see differences in perception across people?
Differences due to transduction:
Diversity due to transduction
Diversity due to experience
Cultural diversity in color perception
Winawer ET AL 2007
Cultural diversity in color perception
Background: Unlike English, Russian distinguishes between lighter blues (“goluboy”) and darker blues (“siniy”)
Method:
A blur ‘test square’ appears on the screen, followed by two options
Select the option that matches the test square
Results:
Russian speakers faster to discriminate two colors when they fell into different linguistic categories (one light, one dark) than when they are in the same linguistic category
English speakers did not show any difference in discriminating different shades of blue
Take home message:
Language, which is a product of culture, affects perception of color
Revisiting research:
Winerwar compared English and Russian speakers on how quickly the were able to match blue squares to a standard
Bottom up processing
No experience or context related to the stimuli; must focus on its individual ‘parts’ and try to construct something that is meaningful from them
Relies heavily on the S2 (the rider)
Top down processing
Past experience and/or context allow for very quick perception of the stimulus
Relies heavily on the S1 (the elephant)
absolute threshold
The minimum amount of physical energy that can be detected 50% of the time
Difference threshold
minimum difference in physical energy between two stimuli that can be detected 50% of the time
three characteristics of light that are processed by the eye
- Hues - various colours of light red, organic, yellow, green, blue, violet, indigo all relate to a wavelength picked up by the eye
- Saturation - is a very pure form of color, intense color fire truck red is more saturated than brick red
- Amplitude - or height of light waves. Taller or have a greater amplitude will appear brighter in intense high-energy illumination and more dull and drab in dim light
