attention and perception 8A-D

attention

actively focusing on particular information while simultaneously ignoring other information

internal stimuli

information or sensations that originate from within the body

external stimuli

information or sensations that originate from outside the body

sustained attention

focusing on one stimulus or task across a prolonged continuous period of time

distractions

stimuli that draw attention away from the current task

divided attention

splitting attention across two or more stimuli at one time

multitasking

the act of working on multiple tasks at one time

selective attention

exclusively focusing on a specific stimulus or task while ignoring all other stimuli or tasks

sensation

the process of receiving and detecting raw sensory information via the sensory organs and sending it to the brain

three stages of sensation

reception, transduction, transmission

reception

when a sensory stimulus is first detected by a sensory organ

transduction

the conversion of raw sensory information detected by sensory receptors into a form that can be sent to the brain

transmission

the process of sending sensory information as a neural impulse to the part of the brain responsible for processing that sensory information

perception

the process of selecting, organising and interpreting information to be able to understand it

three stages of perception

selection, organisation, interpretation

selection

the process of attending to certain features of sensory stimuli to the exclusion of others

organisation

the process of regrouping features of sensory stimuli together to form cohesive and meaningful information

interpretation

the process of understanding and assigning meaning to sensory information

eye

the sensory organ responsible for receiving light to enable vision

cornea

a transparent, convex-shaped covering which protects the eye and helps to focus light rays onto the retina at the back of the eye

pupil

an opening in the iris that helps to control the amount of light entering the eye

lens

focuses the light that enters the eye onto the retina by bulging or flattening according to how far away an object is

retina

a layer at the back of the eye that receives and absorbs light and processes images

photoreceptors

sensory receptors on the retina which receive light and convert this sensory information into a form that can be sent to the brain - includes rods and cones

rods

photoreceptors that allow for vision in low levels of light

cones

photoreceptors that allow for colour vision and fine detail in well-lit conditions

optic nerve

a bundle of neurons that transmits neural impulses from the eye to the brain - exits the eye at the back of the retina

blind spot

a small area of the retina where the optic nerve exits, and where there are no photoreceptors (so that no light can be detected there)

the process of visual perception can be understood as largely influenced by

biological, psychological and/or social factors

perceptual set

a predisposition to perceive certain features of sensory stimuli and ignore other features that are deemed irrelevant

visual perception principles

guiding rules that we automatically and unconsciously apply to incoming visual signals - determine how we organise and interpret the visual data that we receive

gestalt principles

guiding rules of perception that allow us to organise and group separate visual stimuli into a meaningful whole

gestalt principles include the

figure-ground, proximity, similarity and closure principles

figure-ground principle

involves our brain's tendency to see some figures as being at the front of an image i.e. the "foreground" and others as falling back into the "background"

proximity principle

the brain's tendency to group together items in an image, based on their physical closeness to one another

similarity principle

the brain's tendency to group together parts of an image that are similar in some way (e.g. size, shape, colour, position)

closure principle

the brain's ability to mentally compare images that are otherwise incomplete

visual constancies

the ability to perceive visual objects as staying the same, even though they may appear to change or do change in our sensation

visual constancies include the

shape, size and brightness constancy

shape constancy

the tendency to perceive an object as maintaining its shape despite any changes in the shape of the image of the object on the retina

size constancy

the ability to recognise that an object's actual size remains the same, even though the size of the image it casts on each retina change

brightness constancy

the tendency to perceive an object as maintaining its level of brightness in relation to its surroundings, despite changes in the amount of light being reflected from the object to the retina

depth cues

visual cues that allow someone to perceive the world in three dimensions and judge the distance and position of objects in their environment

depth cues include the

monocular and binocular depth cues

monocular depth cues

rely on visual information received by just one eye

pictorial depth cues

a type of monocular depth cue that is classified as a psychological factor

pictorial depth cues include the

interposition/overlap, texture gradient, relative size, height in visual field and linear perspective

interposition/overlap

when an object overlaps another object, it is perceived as closer than the one it covers

texture gradient

we rely on the use of texture to judge how far away objects are - the closer we are, the greater the detail of texture we can see

relative size

the relative size of objects to one another in our visual field helps us to judge distance

height in visual field

in our visual field, the closer objects are to the horizon, the further away they appear

linear perspective

parallel lines within our visual field appear to gradually come together as they recede into the distance, but are separated up close

biological types of monocular depth cues include

motion parallax and accommodation

motion parallax

uses our perception of movement to help us gauge how far away things are - the less objects in our visual field more, the further away they appear from us

accommodation

involves our lens bulging and flattening according to how far away an object is

binocular depth cues

rely on visual information from both eyes

binocular depth cues include

retinal disparity and convergence

retinal disparity

the difference or "disparity" between the different images received on the retina of either eye - the closer an object, the greater the disparity

convergence

when we look at things up close, our eyes turn inwards and our eye muscles are strained - the strain produces signals to our brain that something is up close