PSYC 100A Study Guide - Final Guide: Gustav Fechner, Necker Cube, Subliminal Stimuli
1 May 2018
School
Department
Course
Professor
psych review:
(chapters 6, 7, 8, 9)
Sensation:
1. definitions and basics of sensation and perception
Sensation:
-the detection of physical energy edited or reflected by physical objects
Perception:
-the set of processes that organize and interpret sensory impulses. Allows us to identify
objects
Necker Cube:
-allows for the perception of two different cubes
Source of our perception: sensory experience
Transduction:
-conversion of one type of energy to another
-sense receptors = biological transducers (encodes information into anatomical code —>
neural impulses)
Johanne Muller (1826)
-Doctrine of Specific Nerve Energies
-specific types of sensation accompany certain sensory nerved
-sensory pathways separate
ex: any stimulation of visual nerves leads to sensation of light (push on your eyes, lights up)
in contrast: synthesis (blending of pathways)
Synesthesia
-tasting shapes, hearing colours
ex: video: guy with synesthesia
-tests: a bunch of 5’s and 2’s, most people would not see them but people with synesthesia
often associate letters and numbers with a different colour.
-often have amazing spelling.
2. Psychophysics
Early Sensory Studies
Gustav Theodor Fechner:
find more resources at oneclass.com
find more resources at oneclass.com
-psychophysics
-coined the “two-point threshold” —> points of the skin, how far
apart should they be before the body senses them as separate
sensations.
-and “just noticeable difference”
-dealing with sound, tests etc.
Psychophysics:
-an exact science to establish mathematical relationships between physical and psychic
magnitude
-trying to understand psyche and how it related to body
-solving mind body problem be establishing mathematical relationships between phsycisal
stimulation
Absolute Threshold:
-Limen of minimal intensity for conscious sensation (may know SUBlimenal)
-point at which stimuli are weak at intensity, at such a level where we are only 50% accurate at
identifying whether they are present
-the point @ which you can correctly identify stimulation in 50% of trials.
(brightness, loudness, smelling)
Difference Threshold
-change in intensity for JND - smallest difference that is noticeable
-examined how much change in energy is required in order to perceive difference:
shows up in:
Weber’s Law
-the size of change needed to be perceived:
-varies against background level to produce a constant proportion (JND)
-“just noticeable difference:
Ex: The Weber-Fechner Function:
S = K log R
-sensation is LOGARITHMIC:
-the louder something gets the more noticeable the difference.
Subliminal Perception
-studies done to consider whether we can be influenced subliminally
-Greenwald showed there is no such effect
-For fechner, this was when we can CONSCIOUSLY perceive things below absolute
threshhold, conscious but not as accurate
-after fechner: development of people researching subliminal influences.
Priming
-has impact
-related to mere exposure effect:
-we tend to prefer things that we have had a brief exposure to over those that are novel
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find more resources at oneclass.com
Sensory Adaptation:
-The reduction of sensory responsiveness when a stimulus is unchanging or repetitive
-can adjust or adapt to changing levels of stimulation
Sensory Deprivation
-that absence of “normal” levels of sensory stimulation
-studies said can lead to anxiety and hallucinations
-BUT: participants may have been INFLUENCED be expectations such as panic buttons
and release from liability wavers
-common practice today: sensory deprivation tanks
Sensory Overload:
-too much noise and excitement can be discomforting and cause fatigue, mental confusion,
and STRESS (relateable)
-this is sometimes used for brainwashing or coercively influencing people.
REGARDLESS we can selectively attend:
Selective Attention
-focusing of attention on selected aspects of environment and the “blocking” of others
ex: “Cocktail Party Phenomenon”
-lots of noise and distractions but you can still recognize your name being said
-partial awareness to everything but some things get a fuller awareness
3. Vision
Light:
-part of the EMR spectrum that extends from short UV through to long infra-red
-height of wave is intensity
i. Hue = related to the WAVE LENGTH of light
ii. Brightness (or luminance) = related to AMOUNT OF LIGHT EMITTED or reflected by an
object
iii. Saturation = the VIVIDNESS or PURITY of colour; complexity of light waves (number of
different wave lengths contained in a light source)
4. The Eye and its Functions
STRUCTURE:
cornea: CLEAR PART, light travels through here to pupil
Pupil:
-light enters through here
-goes down to retina
Retina:
(from front to back)
-light travels thru tissue and blood vessels
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Sensation: de nitions and basics of sensation and perception. The detection of physical energy edited or re ected by physical objects. The set of processes that organize and interpret sensory impulses. Allows for the perception of two different cubes. Conversion of one type of energy to another. Sense receptors = biological transducers (encodes information into anatomical code > neural impulses) Speci c types of sensation accompany certain sensory nerved. Sensory pathways separate ex: any stimulation of visual nerves leads to sensation of light (push on your eyes, lights up) in contrast: synthesis (blending of pathways) Tasting shapes, hearing colours ex: video: guy with synesthesia. Tests: a bunch of 5"s and 2"s, most people would not see them but people with synesthesia often associate letters and numbers with a different colour. Coined the two-point threshold > points of the skin, how far apart should they be before the body senses them as separate sensations.
