Psych unit 4 - sensation and perception

Sensation

The process of detecting information from the enviornment that meets a certain threshold and translucent stimuli into neurochemical messages for processing (perception) in the brain.

Transduction

Process where you turn sensory energy (light or sound) into neural signals so the brain can understand

Absolute Threshold

The smallest possible stimulus that can be detected 50% of the time 

Just noticeable difference 

Smallest difference between two stimuli that can be detected 50% of the time 

Webers Law 

The degree to which stimuli can be detected at least 50% of the time 

Sensory interaction

The sensory systems constantly work together

Top Down processing

Knowledge gained from prior experience. Has stimuli to perceive them

Bottom up

Raw information that enters through our sense organs, no prior knowledge

Sensory Adaption 

The reduced response to unchanging stimulus. After constant exposure to a stimulus, nerve cells fire less frequently 

Synesthesia

Experience of sensation in which one system of sensation is experienced through another

Selective Attention

Prioritize input

Inattention

Failure to see a secondary event while performing another visual task

Change Attention

Failure to see changes in your visual environment after an interruption

Retina

The photosensitive surface at the back of the eye. Cells in the retina capture visual informático that is transducer to the brain for processing

Rods

In retina - Black and white (peripheral), dim light

Cones 

In retina - color, detail 

Ganglion

Transmits signals to optic nerve

Blind spot

Near the retina and where the visual nerve exits the eye

Accommodation

Visual stimuli are focused onto the retina by the lens. When this process is altered, nearsightedness or farsightedness can occur

Trichromatic Color theory 

3 color receptors (red,yellow,blue) 

Opponent Process

Pairs (red-green, blue-yellow, black-white)

Damage to the occipital lobes result in

Disorders such as prosopagnosia (face blindness) and blindsight

Wavelengths

Pitch

Amplitudes

Loudness

Place theory 

Different pitches = different cochlea areas

Frequency

Rank of neural firing matches frequency

Volley

Neurons alternate firing for high pitch

Sensorineural deafness

Inner ear or nerve damage, damage to the hair cells or auditory nerve

Conduction hearing loss

Damage to the mechanical system that conducts sound (eardrum or ossicles) 

Olfactory bulb

The structure above the nasal cavity that process smell signals from receptor cells

Gustation

Sense of taste

Types of tastes

Sweet, sour, salty, bitter, umami, and oleogustus

Kinesthetic sense

Sense of body part position and movement 

Vestibular sense 

Sense of balance and body orientation; located in inner ear (semicircular canal)

Gate control 

The spinal cord acts as a “gate” that can block or allow pain signals to pass the brain 

Biopsycholosocial

Pain is influences by biological, psychological, and social factors

Gestalt principles of organization

Proximity, similarity, closure, continuity, figure ground

Perceptual constancies

Size, shape, and color

Retinal disparity 

Difference between images in each eye; greater disparity = closer object 

Convergence

Eyes move inward to focus on near objects

Monocular depth cues

Interposition: closer objects block farther ones

Linear: lines converge

Texture: become hazy as distance increases

Shadow: gives depth 

Relative size: further away = smaller size 

Relative motion = as you move, nearby objects appear to move 

Stroboscopic

Perceiving motion from a rapid series of still images. E.x animation

Phi phenomenon

Illusion of movement

Perceptual set

A mental predisposition to perceive things a certain way based on expectations, experience, and context