PSYC 1F90 SENSATIONS

Transduction

The process by which sensory organs covert energy form the environment into electrical energy through action potentials that can be understood by the brain. E.g. The eyes translate light energy, ears translate mechanical energy, tongue translates chemical energy.

Psychophysics

Study of how the mind interoperates the physical properties of stimuli.

Absolute threshold

Minimum mount of physical energy that can be detected 50 percent of the time.

Difference threshold

Minimum difference in psychical energy between two stimuli that can be detected 50 prevent of the time.

Sensory adaptation

A decrease overtime in sensory responding to an unchanging stimuli.

Hue

the colour of light, determined by its wavelength.

Saturation

The purity of a colour.

Brightness

The intensity of a colour, determined by the amplitude of the light wave

Cornea

Curved, transparent, protective layer through which light enters the eye

Lens

Clear structure behind the pupil that bends light towards the cornea

Sight accommodation

Changing the shape of the eye lens that enable us to clearly see objects close or far.

Hyperopia

Difficulty focusing on nearby objects

Myopia

Difficulty focusing on far away objects.

Astigmatism

Defects in the cornea, lens, or eye that fuzzes our vision.

Presbyopia

Aging loss of vision

Photoreceptors

 Light sensitive cells responsible for transducing light waves

Blind spot

Area in the retina with no photoreceptors (Optic nerve)

Optic nerve

 Carries info from retina to brain

Fovea

 Tiny spot in the retina center containing only cones

Trichromatic theory

The theory of having three cones to detect colour

Opponent-process theory

Colour vision is based on seeing things as red or green, yellow or blue, black or white.

Pitch

how high or low a tone sounds based on the frequency of the wave

Loudness

The intensity of a sound based on the height of the wave

Eardrum

Membrane that vibrates in response to sound waves and transmits them inwards

Ossicles

Small bones in the ear that are associated with transduction

Cochlea

 Snail shaped organ in the inner ear that contains sensory receptors for hearing

Basilar membrane

Structure in the cochlea containing hair cells that convert sound waves into action potentials.

Conductive hearing loss

Poor transfer of sound from the eardrum to the inner ear

Sensorineural hearing loss

Damage to the inner ear hair cells.

Frequency theory

Pitch is decoded from the rate at which hair cells are firing

Place theory (hearing)

 Higher and lower tones excite different places of the cochlea.

Olfaction

Smell

Gustation

Taste

Kinesthetic sense

Body movement and positioning

Vestibular sense

Balance, gravity, and acceleration

Anosmia

inability to smell a specific odor

Lock and key olfaction (smell) theory

Odors are related to the shapes of chemical molecules.

Anaphia

The inability to experience touch

Mechanoreceptors

Provide information about contact, touching, pressure, texture, and pulling

Thermoreceptors

Provide information about temperature

Nocireceptors

 Provide information about pain

Multimodal integration

The brain combines information coming from more than one sense

Selective attention

Giving priority to a particular incoming sensory message

Perceptual construction

Mental model of external events

Figure ground organization

Organizing stimuli so that there is a recognizable figure and background.

Shape consistency

 The perceived shape of an object is unaffected by changes in the retinal image

Size consistency

The perceived size of an object remains consistent.

Brightness consistency

The apparent brightness of an object remains the same so long as it is illuminated by the same amount of light.

Muller-lyer illusion

Two equal length lines tipped with inward and outward arrow heads appear to be different lengths.

Depth perception

Our ability to see three dimensional space and to judge distances accurately.

Depth cues

Features of the environment and messages from the body that supply information about distance and space

Binocular depth cues

 Perceptual features that require two eyes to impart information about three dimensional space

Retinal disparity

The differences between the images each eye projects

Stereoscopic vision

Perception of space and depth as a result of each eye receiving a different image

Convergence (sight)

Degree to which the eyes turn to focus on a close object

Monocular depth cues

Perceptual features that only require one eye to impart information about depth and space

Pictural depth cues

 Monocular depth cues found in paintings and two dimensional art works.