Chapter 4 Flashcards
Device that convert one kind of energy into another
Transducers
The process of detecting physical energies with sensory organs
Sensation
Mental process of organising sensation into meaningful patterns
Perception
Study of relationship between physical stimuli and sensations they evoke in a human observer
Psychophysics
The minimum amount of physical energy necessary to produce a sensation
Absolute threshold
A decrease in sensory response to an unchanging stimulus
Sensory adaptation
Separation of sensory information into important elements
Sensory analysis
Basic elements of a stimulus, such as lines, shapes, edges or colours
Perceptual features
Neural signals that sense organs use to transmit info to the brain
Sensory coding
The minimum difference between two stimuli that is detectable to an observer
Difference threshold
Giving priority to a particular incoming sensory message (focus on book while not noticing the sensation of back against chair)
Selective attention
A failure to notice a stimulus because attention in focused elsewhere
Inattentional blindness
Type of sensation you experience depends on which area the brain is activated
Sensory localisation
Narrow spread of the electromagnetic spectrum to which the eyes respond
Visible spectrum
Basic colour categories corresponding differently to light wavelengths
Hue
Degree to which wavelengths of light are “pure” or “mixed”
Saturation
Amplitude/height of light waves
Brightness
Coloured circular muscle that controls amount of light entering eye
Iris
Opening at front of eye through which light passes
Pupil
Transparent membrane covering the front of the eye - bends light rays inwards
Cornea
Structure in the eye that focuses on light rays
Lens
Changes in shape of the lens of the eye to focus light on the retina
Accomodation
Four Visual Problems
Hyperopia, Myopia, Astigmatism, Presbyopia
Hyperopia
Difficulty focusing on nearby objects (farsighted)
Myopia
Difficulty focusing on far away objects (nearsighted)
Astigmatism
Corneal or lens defect - causes some area to be out of focus
Presbyopia
Difficulty focusing cause by loss of flexibility in lens due to ageing
Light sensitive layer at back of the eye
Retina
Light sensitive cells in the retina
Photoreceptors
Photoreceptors - colors and bright light - 5 million in each eye
Cones
Photoreceptors - dim light - produce black and white - about 120 million in each eye
Rods
Area of retina lacking photoreceptors
Blind spot
Sharpness of visual perception
Visual acuity
Area at center of retina containing only cone (sharp image) containing only cones
Fovea
Vision at edges of visual field
Peripheral vision
Loss of peripheral vision
Tunnel vision
Colour vision theory that states we have 3 cone types: red, green and blue (other colours are a combination of these)
Trichronatic theory
Theory of colour vision based on three coding systems (red/green, yellow/blue, black/white)
Opponent process theory
Visual sensation that remains after stimulus is removed
Afterimage
Inabikity to perceive colours; lack cones or malfunctioning cones
Colour blindness
Inability to distinguish some colours (red-green most common - more in men than women - sex-linked - recessive)
Colour weakness
Test for colour blindness and colot weakness
Ishihara test
Increased retinal sensitivity to light after entering the dark; going from daylight into dark movie theatre
Dark adaptation