ch 4

Sensation

Detecting physical energy from the environment and encoding it as neural signals

Bottom-Up Processing

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

Externally Driven.

Perception

Selecting, organizing, and interpreting what comes in your window as meaningful objects and events.

Top-Down Processing

Guided by higher level mental processes, such as experience, motivation, and expectations

Perceptual Adaptation

Ability to adjust to an artificially displaced field

Psychophysics

The study of how physical energy relates to our psychological experience

Transduction

Conversion of one form of energy into another

Absolute Threshold

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

Difference Threshold

(JND)

The minimum difference a person can detect between any 2 stimuli 50% of the time

Weber's Law

Difference thresholds differ by a constant percentage rather than a constant amount.

Signal Detection Theory

Predicts when we will detect weak stimuli amid background noise

Subliminal Messages

Stimuli below one's absolute threshold

Works to an extent

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation

Wavelength

Determines Hue

Amplitude

Determines Brightness

Pupil

A small adjustable opening in the center of the eye through which light enters

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil's opening

Cornea

Protects the eye and bends light to provide focus

Lens

The transparent structure behind the pupil that changes shape to help focus objects on the retina

Accomodation

Lens changes shape to focus near or far images on the retina

Retina

Light sensitive inner surface of the eye containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

Optic Nerve

The nerve that carries neural impulses from the eye to the brain

Blind Spot

The point at which the optic nerve leaves the eye

Fovea

The central focal point in the retina

Acuity

Resolution

Nearsightedness

Too much curvature of the cornea/lens

Farsightedness

Not enough curvature of the cornea/lens

Rods

Retinal receptors that detect black, white, and grey

Cones

Retinal receptors that are concentrated near the center of the retina

Feature Detectors

Nerve cells in the brain the respond to specific features of the stimulus, such as shape, angles, or movement

Parallel Processing

The processing of many aspects of a problem simultaneously

Trichromatic Theory of Color Vision

The eye has 3 types of color receptors (red, green, and blue)

Color Blind

People who lack a chemical produced by one or more types of cones

Opponent Process Theory of Color Vision

Certain neurons can be either excited or inhibited depending on the wavelength of light

Wavelength

Pitch

Amplitude

Loudness

Decibels

Unit of measurement for sound

Transduction in the Ear

Vibration/mechanical energy -> neural impulses

Hair Cells

Bent by the vibrations and transduce mechanical energy to neural impulses

Frequency Theory

The theory that the rate of nerve impulses travelling up the auditory nerve matches the frequency of a sound

Place Theory

The theory that links pitch with the place where the cochlea's membrane is stimulated.

Conduction Deafness

Caused by damage to the mechanical system that conducts sound waves to the cochlea

Sensorineural Deafness

Caused by damage to the cochlea's receptor cells or to the auditory nerves

Four Skin Senses

Pressure, Warmth, Cold, and Pain

Gate Control Theory of Pain

The spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass onto the brain

Five Taste Sensations

Sweet. Salty, Bitter, Sour, Umami

Gestalt Psychology

Emphasize the tendency to integrate pieces of information into meaningful wholes

Figure Ground Relationship

The organization of the visual field into objects that stand out from their surroundings

Proximity

We group nearby objects together

Similarity

We group similar objects together

Continuity

We perceive smooth continuous patterns rather than disconnected ones

Connectedness

Uniform and Linked

Depth Perception

The ability to see objects in 3D although the images that strike the retina are 2D

Allows us to judge distance

Monocular Cues

Available to either eye alone

Linear Perspective

Parallel lines appear to converge with distance

The more they converge, the greater their perceived distance

Interposition

If one object partially blocks our view of another, we perceive it as closer

Relative Size

If we assume 2 objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away

Relative Height

We perceive objects higher in our field of vision as farther away

Light and Shadow

Nearby objects reflect more light to our eyes

Dimmer seems farther away

Binocular Cues

Depends on both eyes

Retinal Disparity

By comparing the images from the retinas in the 2 eyes, the brain computes distance

Greater the difference/disparity the closer the object

Phi Phenomenon

An illusion of movement created when two or more adjacent lights blink on and off in quick succession

Perceptual Constancy

Perceiving objects as unchanging even as illumination and retinal images change

Consistent shape, size, lightness, and color

Perceptual Set

A mental predisposition to perceive one thing and not another

Extrasensory Perception (ESP)

Claim that perception can occur apart from sensory input

Telepathy

One person sending thoughts to another or perceiving another's thoughts

Clairvoyance

Perceiving remote events

Precognition

Perceiving future events

Psychokinesis

"Mind over matter"

Visual Capture

The tendency for vision to dominate the other senses

Papillae

Tiny bumps on the surface of the tongue covered in taste buds

5 Taste Sensations

Sweet, salty, bitter, sour, umami

Olfactory Bulb

Brain structure responsible for our sense of smell

Processes info about odors after receiving sensory input form the nose

Kinesthetic Sense

The system for sensing the position and movement of individual body parts

Vestibular Sense

The sense of body movement and position, including the sense of balance

Selective Attention

The focusing of conscious awareness on a particular stimulus

Cocktail Party Effect

Being able to focus one's attention on a particular stimulus while filtering out a range of other stimuli

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere

Change Blindness

Failing to notice change in the environment

Visual Cliff Experiment

Tested depth perception in infants

Human Factors Psychology

A branch of psychology the explore how people and machines interact and how machines and physical environments can be made safe and easy to use

Parapsychology

The study of paranormal phenomena

Including ESP and Psychokinesis

Decibels

Unit of measurement for sound

(dB)

Transduction in the Ear

Depends on experience, expectations, motivation, and fatigue level

Unconsciously sensed

No receptor cells

Brain fills the "hole" without permission

Near objects are more clear