Chapter 3 - Sensation & Perception Flashcards
What is the stimulation of sensory receptors in the transmission of sensory information to the central nervous system?
Sensation
What is the process by which Sunsations are organized into an inner representation of the world?
Perception
Who proposed the term for the minimal amount of energy that can produce association as a measure of a sensation, known as absolute threshold?
Gustav Fechner
What is defined as the weakest stimulus they can activate the sensory system 50% of the time?
Absolute threshold
What is the perception that occurs below conscious awareness for a signal that is below the absolute threshold?
Subliminal perception
What perception may subtly influence an individual’s attitude?
Subliminal perception
What is the minimum difference in intensity require between two stimuli to be perceived as being different?
Difference threshold
What is the fraction of the intensity by which stimuli must be increased/decreased to be able to be perceived as different stimuli?
Weber’s constant
What is weber’s constant for intensity of light?
2%
What is known as “just noticeable difference”?
Weber’s constant
What is the signal detection theory?
The perception of sensory stimuli is an interaction of physical, biological and psychological factors
What does perception depend on in an individual?
Training/learning, motivation, alertness, interest, and experience
What are featured detectors in the brain?
Specialized neurons that fire in response to specific features of sensory information
What is sensory adaptation?
Process by which organisms respond to the magnitude of incoming stimuli
What occurs when we become more sensitive to stimuli of low magnitude?
Sensitization or positive adaptation
What occurs when we become less sensitive to stimuli that remain the same?
Desensitization or negative adaptation
What makes up 80% of the world around us?
Vision
What is visible light?
Part of the spectrum of electromagnetic energy that’s detectible to the human eye
What is the colour of light is determined by its wavelength?
Hue
What part of the spectrum of electromagnetic energy is not visible to humans?
X-rays and ultraviolet rays
Where does light enter the eye through?
Cornea
What is a muscular membrane regulating the amount of light by constricting/dilating?
Iris
What is the opening of the Iris?
Pupil
What is behind the Iris, focusing the image on the retina?
Lens
What is the photosensitive inner surface of the eye, with specialized receptors - rods and cones?
Retina
What are neurons to conduct neural impulses from rods and cones to ganglion cells?
Bipolar cells
What are ganglion cells?
Neurons whose axons form the optic nerve
What is a nerve that transmits sensory information from the eye to the brain?
Optic nerve
What are the rod shaped photo receptors that are sensitive only to the intensity of light, providing vision in black and white and denture on the periphery of the fovea?
Rods
Who has more rods, men or women?
Men
What are cones?
Cone-shaped photo receptors that transmit sensations of and visual acuity
- most densely packed at the fovea
What is an area near the centre of the retina that is dense with cones and where vision is consequently most acute?
Fovea
Which photo receptor is throughout the fovea?
Rods
What is the blind spot?
Area of the retina where axons from ganglion cells meet to form the optic nerve
What is visual acuity?
Sharpness of vision
What is the term for being able to see things up close?
Near sighted
What is the process of adjusting to conditions of lower lighting by increasing the sensitivity of rods and cones?
Dark adaptation
How long does it take for rods and cones to adapt to the dark?
About 10 minutes for cones and up to 45 for rods
What is the process of adjusting to bright light?
Light adaptation
How long does it take to adapt to the light?
About one minute. It floods retina with too much data and Iris is trying to catch up
What are the perceptual dimensions of color?
Hue, value, saturation
What is the definition of value?
Degree of lightness or darkness
What is the definition of saturation?
How intense a colour appears to us
What is the trichromatic theory?
Colour vision is made possible by three cones that are sensitive to either red, green or blue
What is the opponent-process theory?
Colour vision is made possible by three cones/color receptors:
red-green
blue-yellow
light-dark
The brain integrates input from all three to perceive colours
What is a trichromat defined as?
A person with normal colour vision
What is it Monochromat defined as?
Fully color blind, has vision in black and white
What is a dichromat defined as?
Person with partial color blindness, can discriminate between two colours
- more common in males
What is visual perception?
Process by which we organize/make sense of the sensory impressions caused by our knowledge, expectations and motivations
What do Gestalt psychologists note about perceptual organization?
certain consistencies/rules in the way we integrate bits and pieces of sensory stimulation into meaningful wholes - called the laws of perceptual organization
What allows us to separate the object of interest and the background?
Figure-ground perception
What are gestalt rules for organization?
Closure, proximity/nearness, similarity, continuity and common fate
What is the tendency to perceive a broken figure as being complete or whole?
Closure?
What is the perceptual tendency to group together objects that are near one another?
Proximity/nearness
What is the perceptual tendency to group together objects that are similar in appearance?
Similarity
What is the tendency to perceive a series of points or lines as having unity?
Continuity
What is the tendency to perceive elements that move together as belonging together?
Common fate
What is top-down processing?
Use of contextual information or knowledge of a pattern in order to organize parts of the pattern (perception of whole followed by perception of parts)
What is bottom-up processing?
Organization of parts of a pattern to recognize the pattern they compose (perception of parts leads to perception of whole)
What is the visual perception of motion is based on a change of position relative to other objects?
Perception of motion
What are sensations that give rise to misperceptions?
Illusions
What is the perception of motion generated by a series of stationary images presented in rapid succession?
Stroboscopic motion (1st motion pictures)
What are monocular cues?
Stimuli suggestive of depth that can be perceived with only one “mono” eye
What are the different Monocular cues?
Perspective, size constantly, overlapping, shadows, Textra gradient, motion parallax
What are stimuli suggestive of depth that involve simultaneous perception by both eyes?
Binocular cues
What is retinal disparity?
Cue to depth perception based on the difference between the images cast on the retina by each eye as the object moves closer or farther away
What is the cue to depth perception based on the inward motion of eyes as an object moves closer?
Convergence
What are the perceptual Constancies?
Size constancy, color constancy, brightness constancy, shape constancy
What is the purpose of perceptual constancies?
Enable us to recognize objects even when their apparent shape or size differs
What occur when the principles of perception cause us to interpret visual input incorrectly?
Visual illusions
What is the failure to notice things around us because our attention is focused elsewhere?
Inattentional blindness
What is change blindness?
Failure to notice changes around us, even when we are looking right at them
What is the ventral stream?
Creates mental representation or perceptions of everything we see
What is the dorsal stream?
Informs our muscles on how to act toward objects in our world
How does sound travel?
Waves
What kind of medium does a sound wave require?
Air or water
What is the sensitivity of a human ear to sound waves?
Broad range of sensitivity, 20 to 20,000 waves or cycles per second
What is pitch measured as?
Frequency
How is loudness measured?
Amplitude of sound waves do you
What is the unit expressing the loudness of a sound?
Decibel
What is the ear shaped and structured to do?
Capture sound waves, vibrate and sympathy with them, transmit auditory information to the brain
What are the three parts of the ear?
Outer ear, middle ear, inner ear
Which part of the ear funnels sound waves to the eardrum, which transmit sound waves to the middle and inner ears?
Outer ear
What part of the ear consists of the eardrum and three tiny bones?
Middle ear
Which part of the ear acts as an amplifier?
Middle ear
Where is the cochlea?
Inner ear
What is the membrane that lies coiled within the cochlea?
Basilar membrane
What is the receptor for hearing that lies on the basilar membrane?
Organ of Corti
What is the command post of hearing?
Organ of Corti
What does the relative loudness of the sound in each ear provide?
Directional information
What is the perception of loudness and pitch related to?
Number of receptor neurons in the organ of Corti
What is the place theory?
Pitch of a sound is determined by the section of the basilar membrane that vibrates in response to the sound
What is the frequency theory?
Pitch of a sound is reflected in the frequency of the neural impulses that are generated in response to the sound
What is conductive deafness?
Damage to structures of middle ear
What is sensoneurinal deafness?
Damage to inner ear or auditory nerve
What is the flavour of food based on?
Odour, texture and temperature
What is the other name for taste?
Gustation
How many taste buds do humans have?
About 10,000
What does perceived flavour depend on?
Odor, texture, temperature and taste
What is a person who experiences taste sensation more intensely, due to having a greater amount of taste buds
Supertaster
What is a non-taster?
Person who experiences little to no taste sensation of a particular type
What are the skin senses?
Touch, pressure, temperature and pain
Where are temperature receptors located?
Just beneath the skin
What are nociceptors?
Sensory neurons found in the skin, joints and some organs that respond to damaging stimuli
What are prostaglandins?
Chemicals that facilitate the transmission of pain signals to the brain
Why is the perception of pain subjective?
Our emotional and psychological states affect how we feel pain
What does the Gate-control theory propose?
Nervous system can process only a limited amount of stimulation at a time (rubbing knee after stubbing toe transmits sensations to brain that compete for attention of neurons)
What is phantom limb pain?
Pain can be felt in the missing limbs (have undergone reorganization of motor and somatosensory cortex consistent with pain)
What is kinesthesis?
Sense that informs us about the position and motion of parts of our body
What is the sense of equilibrium that informs us about our bodies positions in space and relative to gravity?
Vestibular sense
What are forms of extra sensory perception?
Pre-cognition, psychokinesis, telepathy, clairvoyance
What do psychologists believe about perception through means other than sensory organs (ESP)?
No rigorous scientific research has generated evidence (only anecdotal experiences from individuals)
