CH. 5 DEFINITIONS [UNIT 2]

Sensation

Awareness resulting from the stimulation of a sense organ

Perception

Organization + interpretation of sensations by the brain

Proprioception

The 6th sense of seeing, hearing, smelling, touching, tasting, and monitoring the body’s positions

Transduction

Conversion of stimuli detected by the receptor cells to electrical impulses that are transported to the brain

Hertz

Unit of frequency that determines vibrations per second

Psychophysics

Branch of psychology that studies the effects of physical stimuli on sensory perceptions and mental states

Absolute Threshold

Defined as the intensity of a stimulus allowing an organism to detech it 50% of the time

Subliminal

It is below the threshold for reliable detection

Signal Detection Analysis

A technique used to determine the ability of the perceiver to separate true signals from background noise

Sensitivity

Individual ability to detect the presence/absence of signals

Judgement/response

refers to the decision about the presence/absence of a stimulus which is independent of sensitivity

Difference threshold/Just noticeable difference (JND)

The change in a stimulus that can just barely be detected by the organism

Weber’s Law

The JND of stimulus is a constant proportion of the original intensity of the stimulus

Subliminal Stimuli

Events that occur below the absolute threshold of our conscious awareness influence our behaviour

Subliminal Advertising

Advertising a product outside of our awareness

Product Placement

Where products like cars, sodas, technology are placed on websites, movies, and TV shows

Blindsight

A condition where people are unable to consciously report on visual stimuli, but are capable of accurately answering questions about what they are seeing

Selective Attention

Ability to focus on some sensory inputs while tuning out others

Cocktail Party Phenomenon

Although selective attention limits what we process, we are simultaneously doing a lot of unconscious monitoring of the world around us

Sensory Adaptation

Decreased sensitivity to a stimulus after a prolonged and constant exposure

Saccades

Our eyes are constantly flitting from one angle to the next, with thousand tiny movements

Perceptual Constancy

The ability to perceive a stimulus as constant despite sensation changes

Electromagnetic Energy

Pulses of energy waves that carry information from place to place

Wave

length

Visible Spectrum

Our eyes only detect the range from 400-700 billionths of a metre on the electromagnetic spectrum

Cornea

Clear covering that protects the eye + focuses on the incoming light

Pupil

Small opening in the centre of the eye

Iris

The coloured part of the eye that controls the size of the pupil by constricting/dilating in response to light intensity

Lens

Structure that focuses the incoming light on the retina

Retina

Layer of tissue at the back of the eye, containing photoreceptor cells

Visual Accommodation

Process of changing the curvature of the lens to keep the light entering the eye focused on the retina

Nearsighted

When the focus is in front of the retina

Far-sighted

When the focus is behind the retina

Presbyopia

Caused by decreased flexibility in the lens

Optic Nerve

Collection of millions of ganglion neurons that send large amounts of visual info, via the thalamus → to the brain

Rods

Visual neurons specializing in detecting black, white, and grey colours

Cones

Visual neurons that specialize in detecting fine detail + colour

Fovea

Central point of the retina

Feature Detector

Specialized neurons located int he visual cortex, responding to the strength, angles, shapes, edges, and movements of a visual stimulus

Hue

Conveyed by the wave-shade of the light that enters the eye

Intensity

Conveyed by the height of the light wave, bigger/intense waves are brighter

Trichromatic Colour Theory

Colour we see depends on the mix of signals from 3 types of cones

Colour Blindness

Inability to detect green/red colours

Opponent-Process Colour Theory

We analyze sensory info not by three colours, but in three sets of opponent colours: red-green, yellow-blue, and white-black

Depth Perception

Ability to perceive 3D space and accurately judge distance

Depth Cues

Messages from our bodies + the external environment that supply us with info about space and distance

Binocular Depth Cues

Depth cues that are created by retinal image disparity (space between our eyes) require coordination of both eyes.

Convergence

Inward turning of our eyes that’s required to focus on objects that are less than ~15m away from us

Accommodation

As the lens changes its curvature to focus on distant/close objects, info relayed from the muscles attached to the lens help us determine an object’s distance

Monocular Depth Cues

Depth cues that help us perceive depth using only one eye

Beta Effect

The perception of motion that occurs when different images are presented next to each other in sucession

Phi Phenomenon

Where we perceive a sensation of motion caused by the appearance and disappearance of objects that are near each other

Frequency

Measured in terms the # of waves that arrive per second, determines our perception of pitch

Pitch

Perceived frequency of a sound

Amplitude (height of sound wave)

determines how much energy it contains and is perceived as loudness

Decibel

Unit of relative loudness

Pinna

The external + visible part of the ear, shaped like a funnel that draws in sound waves, guiding them into the auditory canal

Tympanic Membrane (eardrum)

Tightly stretched, highly sensitive membrane that vibrates with sound waves

Cochlea

Snail-shaped, liquid-filled tube in the inner ear that contains the cilia

Ossicles

Three tiny bones in the middle ear, hammer (malleus), anvil (incus), and stirrup (stapes)

Oval Window

The membrane covering the opening of the cochlea vibrates, disturbing the fluid inside the cochlea

Cilia

Bundle of fibres on hair cells in the cochlea

Place Theory of Hearing

Different areas of the cochlea respond to different frequencies

Frequency Theory of Hearing

Whatever the pitch of a sound wave, nerve impulses of a corresponding frequency will be sent to the auditory nerve

Conductive Hearing Loss

Caused by physical damage to the ear, such as the eardrums/ossicles that reduces the ability of the ear to transfer vibrations from the outer ear → inner ear

Sensorineural Hearing Loss

Caused by damage to the cilia/auditory nerve, less common overall but frequently occurs with age

Tinnitus

Ringing/buzzing sensation after being exposed to loud sounds → damage to the cilia

Cochlear Implant

A device made up of a series of electrodes that are placed inside the cochlea

Taste Buds

Designed to sense chemicals in the mouth

Olfactory Membrane

10-20 million receptor cells that detect airborne chemicals

Olfactory Receptor Cells

Topped with tentacle-like protrusions that contain receptor proteins

Proprioception

Ability to sense the position + movement of our body parts

Vestibular System

Ability to keep track of where the body is moving, set of liquid-filled areas in the inner ear that monitors the head’s position + movement, maintaining the body’s balance

Semicircular Canals

Sense the rotational movements of the body

Vestibular Sacs

Connects the canals with the cochlea

Nociceptors

Nerve endings in organs (skin) that respond to discomfort

Gate Control Theory of Pain

Pain is determined by the operation of two types of nerve fibres in the spinal cord

Sensory Interactions

Working together of different senses to create experiences

McGurk Effect

Error in perception that occurs when we misperceive sounds because the audio/visual parts of the speech are mismatched

Synesthesia

Experience where one sensation creates experiences in another

Illusions

When perceptual processes that normally help us correctly perceive the world around us are fooled by a particular situation, so that we see something that doesn’t exist/incorrect

Mueller

Lyer Illusion

Moon Illusion

The moon is perceived to be about 50% larger when it’s near the horizon > overhead

Human Factors

Field of psychology that uses psychological knowledge, including the principles of sensation + perception, to improve technological development