Perception: Gestalt Principles, Facial Recognition, Pain Sensation, Sleep Stages - Prof. s, Study notes of Psychology

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PSY2012:

Quiz 2 Review

Concepts + Practice Questions

FALL 2023

Chapter 4 Concepts

Just Noticeable Theory

● Relevant to our ability to distinguish a stronger stimulus from a weaker one ○ Ex: soft noise vs a slightly louder noise

● Weber’s law ○ There is a constant proportional relationship between the JND and the original stimulus intensity ○ The stronger the stimulus, the bigger the change needed for a change in stimulus intensity to be noticeable

Absolute Threshold

● The lowest level of a stimulus we can detect on 50 percent of the trials when no other stimuli of that type are present ○ Demonstrates how remarkably sensitive our sensory systems are

● Ex: on a clear night, our visual systems can detect a single candle from 30 miles away

Selective Attention

● Selective attention: allows us to select one sensory channel and turn off the others, or at least turn down their volume ● Filter theory of attention ○ Attention is a bottleneck through which information passes ■ By Donald Broadbent ○ Mental filter slows down the flow of information by enabling us to pay attention to important stimuli and ignore others ○ Dichotic listening: Broadbent tested filter theory of attention with this experiment; participants heard 2 different messages, one delivered to the left ear and one to the right ear

Cocktail Party Effect

● Cocktail party effect: reflects our ability to hone in on one stimulus while we filter out other stimuli ○ Exceptions: when we suddenly hear our own name mentioned in a separate conversation elsewhere in the room ● For heavily practiced activities that become automatic, we have a hard time filtering out information even when we want to ○ Automatic processes are so second-nature they don’t consume attentional resources and aren’t distracting

Theories of Color Vision

Trichromatic Theory ● proposes that we base our color vision on three primary colors (blue, green, and red)

Opponent Process Theory

● we perceive colors in terms of three pairs of opponent cells: red or green, blue or yellow, or black or white ● Explains afterimages

Trichromatic Theory ● Young-Helmholtz trichromatic theory of color vision: Young suggested our vision is sensitive to three primary colors of light; von Helmholtz replicated and extended that proposal by examining the colors that color-blind individuals could see ● Color blindness: ○ Inability to see some or all colors ■ Monochromats: only one type of cone and thereby lose all color vision; extremely rare ■ Most color-blind people can perceive a lot of the world in color because they’re dichromats (have two cones and are missing only one) ● Humans, apes, and some monkeys are trichromats ○ People and our close primate relatives possess three kinds of cones

Major Components of the Ear

Outer Ear ● Consists of the: ○ Pinna: part of the ear we see; its skin and cartilage flap ○ Ear canal: funnels sound waves into the eardrum

Middle Ear ● Contains the ossicles – three tiniest bones in the body named the hammer, anvil, and stirrup ○ Vibrate at the frequency of the sound wave, transmitting it from the eardrum to the inner ear

Inner Ear ● Cochlea converts vibration into neural activity ○ Spiral-shaped; bony; inner cavity is filled with thick fluid ○ Vibrations from sound waves disturb this fluid and travel to the base of the cochlea, where pressure is released and transduction occurs ● Organ of Corti and basilar membrane ⇒ critical to hearing because hair cells are embedded within them

Gestalt Principles of Perception

● Subjective contours: our brains often provide missing information about outlines

● Gestalt principles ○ Describes rules that govern how we perceive objects as wholes within their overall context ○ Help explain why we see our world consist of unified figures of forms instead of jumbles of lines and curves ○ Main 6 principles: proximity, similarity, continuity, closure, symmetry, figure-ground

Gestalt Principles of Perception (3)

Facial Perception

● Prosopagnosia: face blindness; depend on non-facial cues to recognize people (freckles, weight, eyeglasses, clothing) ○ Typically restricted to the face than to stimuli or objects in general ○ Shows the limits of brain plasticity – impairments persist over a lifetime

Aids in Facial Recognition ● Holistic processing: the ability to visualize a face as a whole, rather than the sum of its parts ○ Believed to be crucial to face recognition ● Fusiform gyrus and, within it, the fusiform face area play a central role in the capacity of facial recognition ○ In the temporal lobe ● Sprawling networks of neuron s may be responsible for face recognition

Perception of Pain

● Can be acute (short-lived, chronic) or enduring ● There is a threshold for each kind of pain-producing stimulus ● Emotional component ○ Associated with anxiety, uncertainty, and helplessness ○ Gate control model: idea that pain is blocked from consciousness because neural mechanisms in the spinal cord function as a “gate” where it controls the flow of sensory input to the nervous system ■ Suggests the stimulation we experience competes with and blocks the pain from consciousness ● Placebo effect for pain - may stimulate the body’s production of natural painkillers (endorphins) ● Phantom pain: a sensation of pain or discomfort in the missing limb of people with amputated limbs; about 60 to 80% of amputees experience this ● Research on pain sensitivity shows that pain serves an essential function

Chapter 5 Concepts