Sensation & Perception Flashcards Review

psychophysics

the branch of psychology that deals with the effects of physical stimuli on sensory response

Absolute threshold

the minimal amount of stimulation needed to detect a stimulus and cause the neuron to fire 50% of the time; E.g. the softest sound you can hear or the dim light you can just barely see

Signal detection theory

Examines the four possible outcomes of each trial in a detection experiment:

→ Hit: the signal was present and the participant reported sensing it

→ Miss: the signal was present but the participant did not sense it

→ False alarm: the signal was absent but the participant reported sensing it

→ Correct rejection: the signal was absent and the participant did not report sensing it

Discrimination threshold

the ability to distinguish the difference between two stimuli

Just Noticeable Difference/Difference Threshold

the minimum amount of distance between two stimuli that can be detected as distinct/how much something must change before you note the difference; E.g. you notice your friend’s perfume got a little stronger

Weber’s Law

the greater the magnitude of the stimulus, the larger the differences must be to be noticed; must vary by constant percentage, not constant amount

Subliminal perception

a form of preconscious processing that occurs when we are presented with stimuli so rapidly that we are not consciously aware of them

priming

preconscious processing

Tip-of-the-tongue phenomenon

a form of preconscious information processing in which we try to recall something that we already know is available but is not easily available for conscious awareness

receptor cells

specialized cells designed to detect specific types of energy

the receptive field

the area from which our receptor cells receive input

transduction

when signals are transformed into neural impulses

Sensory coding

the process by which receptors convey such a range of information to the brain

The two types of dimensions a stimulus has:

qualitative and quantitative

Qualitative dimension

coded and expressed by which neurons are firing; E.g. neurons firing in the occipital lobe would indicate that the sensory information is light and neurons firing in the temporal lobe might indicate that the sensory stimulus is sound

Quantitative dimension

coded by the number of cells firing; bright lights and louds noises involve the excitation of more neurons than those brought on by dim lights and quiet noisesS

Single cell recording

a technique by which the firing rate and pattern of a single receptor cell can be measured in response to varying sensory input

Visual sensation

occurs when the eye receives light input from the outside worldd

distal stimulus

the object as it exists in the environment

proximal stimulus

the image of an object on the retina

Cocktail Party Phenomenon

hen you're at a party and everyone is talking loud but then someone calls your name from across the room and your attention involuntarily switches to the person that called your name/ the direction it came from.

Bottom-up processing

starting with what you see and processing it from there

Top-down processing

starting with prior knowledge on what your seeing it and judging it by that

Parallel Processing

thinking about many aspects of a problem simultaneously, the brain's natural mode of processing things, used to recognize faces

Cornea

protective covering; focuses light into the eye

Pupil

lets light into the eye

Iris

the muscles that control the pupil (dilates it and contracts it)

Lens

focuses light from the pupil onto the retina

Cones

→ cells that are activated color

→ concentrated towards the center of the retina

→ the fovea has the most amount of cones

→ detect fine details

Rods

→ Cells that are activated by black and white

→ Outnumbers cones (20:1)

→ Peripheral vision

→ Sensitive to dim light

Trichromatic Theory

→ Hypothesizes that we have three different cones in the retina that process three different colors: Red, blue and green (primary colors of light)

→ Doesn't explain afterimages and color blindness

Opponent Process Theory

→ States that sensory receptors in the retina come in pairs: red/green, yellow/blue, black/white

→ Theory explains color afterimages and colorblindness.

Convergence

the process by which information becomes more complex as it travels through the sensory system, occurring across all sensory systems

serial processing

when the brain computes information step-by-step in a methodical and linear matter

Relative size

Objects that appear smaller are perceived as being farther away.

Texture gradient

The detail of a surface changes with distance — finer/denser textures seem farther away.Textures grow more dense as distance increases.

Interposition occlusion

when a near object partially blocks the view of the object behind it

Linear perspective

parallel lines draw closer together as objects recede into the distance

Vanishing point

point where two lines becomes indistinguishable from a single line and then disappear

Aerial perspective

Objects that are farther away appear bluer, lighter, or hazier due to the scattering of light by the atmosphere.

Relative clarity

Clearer, sharper objects are perceived as closer; hazy or blurry objects seem farther.

Motion parallax

As you move, objects closer to you appear to move faster across your visual field than objects farther away.

Binocular depth cues

rely on both eyes viewing an image

Stereopsis

the three dimensional image of the world resulting from binocular vision

Retinal convergence

a depth cue that results from the fact that your eyes must turn slightly to focus on near objects. The closer the object the more your eyes turn indeed.

Gestalt Approach

Psychological approach emphasizing that we perceive objects as whole patterns or configurations, not just as a collection of parts; Example: Seeing a complete triangle even when only the corners are drawn.

Proximity

Gestalt principle stating that objects close to each other are perceived as a group; Example: Dots clustered together are seen as a single unit.

Similarity

Gestalt principle stating that objects that are similar in shape, color, or size are perceived as part of the same group; Example: Circles of the same color in a grid are seen as related.

Symmetry

Gestalt principle stating that objects that are symmetrical are perceived as belonging together or forming a unified shape; Example: Two mirrored shapes are seen as a single balanced figure.

Continuity

Gestalt principle stating that we perceive lines or patterns as continuing in smooth, uninterrupted paths; Example: A curved line is seen as a continuous path even if it crosses another line.

Closure

Gestalt principle stating that we tend to fill in gaps to perceive a complete object; Example: A broken circle is perceived as a full circle.

Gate Control Theory

Theory of pain perception proposing that pain signals can be blocked or allowed to pass through “gates” in the spinal cord influenced by factors like attention or emotions; Example: Rubbing a bumped knee reduces pain perception because touch signals “close the gate” to pain signals.

Amplitude

height of wave/ how loud the sound is

Frequency

Length of the waves and determines pitch (how deep or high the sound sounds)

Pinna

collects the sound waves

Eardrum (tympanic membrane)

vibrates when the sound waves hit; Vibrations are transmitted by the ossicles (hammer ➡ anvil ➡ stirrup) then go to the oval window

Cochlea

→ snail shapes structure filled with fluid which moves with the vibrations.

→ The floor of the cochlea is the basilar membrane which has hairs cells that are connected to the organ of Corti (neurons activated by the movement in hair cells)

N.B. Balance is controlled by the semicircular canals

Types of Hearing Loss:

1. Sensorineural - Damage to the cochlea’s hair cell receptors or the auditory nerve

2. Conduction - Damage to the mechanical system—the eardrum and middle ear bones—that conducts sound waves to the cochlea

Kinesthesis

the perception of body movement and body location

Sensory adaptation

when you get used to a stimulus and no longer realize it’s there

Sensory habituation

the amount we feel a stimulus is partially based on how much we focus on themS

Sensory dishabituation

occurs when a change in the stimulus causes us to notice it agains

selective attention

by which we try to attend to one thing while ignoring another

Theories explaining selective attention

Filter theories - proposes that stimuli must pass through some form of screen or filter to enter into attention

Attentional Resource theories - posit that we have only a fixed amount of attention and this resource can be divided up as is required in a given situation