perception, senses, sleep/consciousness, drugs

[KA 300 page (1-54)]

visual cues

depth, form, motion, constancy
allows us to perceptually organize information

binocular cues

depth cues, such as retinal disparity and convergence, that depend on the use of two eyes

retinal disparity

a binocular cue for perceiving depth by comparing images from the retinas in the two eyes, the brain computes distance—the greater the disparity (difference) between the two images, the closer the object.

eyes are how far apart from each other?

2.5 inches

convergence

A binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object

eyes when things are far away

muscles of eyes are relaxed

eyes when things are close to us

muscles of eyes contract

monocular cues

depth cues, such as interposition and linear perspective, available to either eye alone

biocular cues give us a sense of

depth

monocular cues give us a sense of

form and motion

relative size

a monocular cue for perceiving depth; the smaller retinal image is farther away

Interposition

overlap
monocular visual cue in which two objects are in the same line of vision and one partially conceals the other, indicating that the first object concealed is further away

relative height

a monocular cue for perceiving depth; objects higher in our field of vision are perceived as farther away

shading/contour

a monocular cue for depth perception; the apparent light source determines whether the surface of an object is perceived as concave or convex

motion parallax

relative motion
a monocular depth cue in which we view objects that are closer to us as moving faster than objects that are further away from us

constancy

the tendency to perceive certain objects in the same way regardless of changing angle, distance, or lighting

types of constancy

size, shape, color

size constancy

the tendency to interpret an object as always being the same actual size, regardless of its distance

shape constancy

the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object (diff colors)

sensory adaptation

tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging

hearing adaptation

inner ear muscle: higher noise = muscle contract (this dampens vibrations in inner ear, protects ear drum.)

Takes a few seconds to kick in! So does not work for immediate noises like a gun shot, but it works for being at a rock concert for an entire afternoon

touch adaptation

temperature receptors desensitized over time

smell adaptation

desensitized receptors in your nose to molecule sensory information over time.

proprioception

sensory information concerning body movements and position of the body in space

sight adaptation

down regulation or up regulation to light intensity

down regulation in eyes

light adaptation

when it is bright out, pupils constrict and rods and cones become desensitized

pupils constrict

less light enters back of eye

up regulation

dark adaptation

pupils dilate - rods and cones start synthesizing light sensitive molecules

Weber's Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

just noticeable difference (JND)

the smallest change in the intensity of a stimulus that we can detect

Weber's law formula

JND= K x I

K = constant
I = initial intensity

Absolute threshold of sensation

minimum intensity of stimulus needed to detect a particular stimulus 50% of the time

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time

subliminal stimuli

stimuli that are below the level of conscious awareness

types of somatosensation

thermoception, mechanoception, nociception, proprioception

Somatosensation

The body senses, including body position, touch, skin temperature, and pain.

thermoception

temperature perception

mechanoception

sensation of pressure

Proprioception

The ability to tell where one's body is in space.

Nociception

perception of pain

intensity

how quickly neurons fire for us to notice

slow neuron firing

low intensity

fast neuron firing

high intensity

non adapting neuron

neuron consistency fires at a constant rate

slow adapting neuron

neuron fires rapidly at first then tapers off

fast adapting neuron

fires as soon as stimulus starts, stops, then starts up again once stimulus stops

dermatomes

an area of the skin supplied by nerves from a single spinal root

vestibular system

three semicircular canals that provide the sense of balance, located in the inner ear and connected to the brain by a nerve

semicircular canals

three canals within the inner ear that contain specialized receptor cells that generate nerve impulses with body movement

endolymph

fluid within the membranous labyrinth of the inner ear

otolithic organs

Utricle and saccule. Detect linear acceleration and head positioning

otolithic organs detect

linear acceleration

otolithic organs contain

CaCO3 crystals attached to hair cells in vicious gel

if we go from lying down to sitting up:

otolithic organs pull on hair cells which triggers AP

dizziness is caused by

endolymph continuing to move after you've stopped moving

signal detection theory

the response to a stimulus depends both on a person's sensitivity to the stimulus in the presence of noise and on a person's response criterion

hit

the subject responded affirmative when a signal was present

miss

subject did not respond when a signal was present

false alarm

the subject perceived a signal when none was present

correct rejection

the subject did not respond when no signal was present

hit > miss

strong signal

hit < miss

weak signal

conservative strategy

always say no unless 100% sure signal is present. Bad thing is might get some misses

liberal strategy

always say yes, even if you get false alarms.

noise distribution

The distribution of possible neural responses to a trial on which no stimulus is present.

signal distribution

values arising when signal + noise present

Ideal observer to signal detection

Difference between signal and noise = d'
d'/2 = ideal observer (maximize hits minimize misses)

difference between signal and noise

d'
if signal is shifted to the left, d' is very small and difficult to detect
if shifted right, it's large and easy to detect

ideal observer

minimizes misses and false alarms

Beta strategy

Set value of threshold to the ratio of height of signal distribution to the height of noise distribution

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

inductive reasoning

A type of logic in which generalizations are based on a large number of specific observations.

deductive reasoning

reasoning in which a conclusion is reached by stating a general principle and then applying that principle to a specific case (The sun rises every morning; therefore, the sun will rise on Tuesday morning.)

Gestalt Principles

ways for the brain to infer missing parts of a picture when a picture is incomplete

similarity

items that are similar tend to be grouped together

Pragnanz

reality is reduced to the simplest form possible (eg Olympic rings)

proximity

objects that are close together are more likely to be perceived as belonging in the same group

continuity

lines are seen as following the smoothest path

closure

objects that make up a recognizable image are more likely to be perceived as belonging in the same group even if the image contains gaps that the mind needs to fill in

symmetry

mind perceives objects as being symmetrical and forming around a center point

law of common fate

The Gestalt principle that we tend to group similar objects together that share a common motion or destination

Law of Past Experiences

Implies that under some circumstances visual stimuli are categorized according to past experience.

contextual effects

the context in which stimuli are presented and the processes of perceptual organization contribute to how people perceive those stimuli (and also that the context can establish the way in which stimuli are organized)

conjuctiva

thin layer of cells
mucous membrane that lines the eyelids and outer surface of the eyeball

cornea

the transparent thick sheet of fibrous tissue
anterior 1/16th
starts to bend light; first part of eye that light hits

anterior chamber

Area behind the cornea and in front of the lens and iris. It contains aqueous humor.

aqueous humor

provide pressure to maintain shape of eyeball
allows nutrients and minerals to supply cells of cornea/iris

pupil

the opening in the middle of the iris that changes size to let in different amounts of light

iris

muscle that expands and contracts to change the size of the opening (pupil) for light

iris does what?

gives the eye color

lens

bends light so it goes to back of eyeball - focuses light specifically on the fovea of the retina. Adjust how much it bends the light by changing its shape, using the suspensory ligaments.

suspensory ligaments

a fibrous membrane that holds the lens of the eye in place

suspensory ligaments are attached to

ciliary muscle

ciliary muscle

muscle that helps focus light on the retina by controlling the curvature of the lens of the eye

ciliary body

Structure surrounding the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.

posterior chamber

area behind the iris to the back of lens; also filled with aqueous humor.

vitreous chamber

the main interior portion of the eye, filled with vitreous humor

vitreous humor

jelly-like substance to provide pressure to eyeball and gives nutrients to inside of eyeball.