Chapter 6: Sensation and Perception

what determines the loudness of a sound?

the amplitude of the sound waves

How do we perceive motion?

moving object will "move" across the retina, triggering neighboring retinal cells

What is a feature detector?

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle or movement -located in the brain's visual cortex

What are receptors that detect pain called?

nocieptors

What is common to all senses?

pain, no single pain nerve, rather pain is encoded within each modality -any stimulus intense enough to cause damage may cause the sensation of pain

What is colour constancy?

perceiving familiar objects as having consistent colour, even if changing illumination alters the wavelengths reflected by the objects

What are rods?

retinal receptors that detect black,white and grey; necessary for peripheral and twilight vision, when cones don't respond

What is the rough distinction between sensation and perception?

sensation is the bottom-up process by which the physical sensory system receives and represents stimuli. Perception is the top-down mental process of organizing and interpreting sensory input.

How does the pain circuit work?

sensory receptors (nociceptors) respond to potentially damaging stimuli by sending an impulse to the spinal cord, which passes the message to the brain, which interprets the signal as pain.

What is bottom-up processing?

starts at the sensory receptions and works up to higher levels of processing

What is Weber's law?

states that for an average person to perceive a difference, two stimuli must differ by a constant proportion (not an exact amount) Ex.: two lights must differ in intensity by 8%

What are the basic taste receptors?

sweet, sour, salty, bitter and umami

What is perceptual adaptation?

the ability to adjust to an artificially displaced or even inverted visual field Ex.: new pair of glasses at first make you feel distorted/dizzy, in a few days you will adjust OR even, lenses that turn the world upside down, you could still adapt

What is depth perception?

the ability to see objects in three-dimensions although the images that strike the retina are two-dimensional; allows us to judge the distance

Define sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

What is transduction?

the process of converting one form of energy into another that your brain can use

Define perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

What is parallel processing?

the processing of many aspects of a problem stimulus at once (colour, motion, form depth)

What is the fovea?

the retina's area of central focus, where the cones cluster in and around

Define audition

the sense or act of hearing

Why is it that after wearing shoes for a while, you cease to notice them?

the shoes provide constant stimulation. Sensory adaptation allows us to focus on changing stimuli.

What is psychophysics?

the study of relationships between the physical characteristics of stimuli and our psychological experiences of them

What 2 physical characteristics of light help us determine our sensory experience?

(1) wavelength: the distance from one peak to the next, determines its hue: the colour we perceive

What is the volley theory?

- Frequency theory cannot explain how higher frequencies are coded. -Volley theory offers an explanation: A single neuron cannot fire at a rate higher than 1000 Hz. But if the neurons fire in a volley (like cannons), then higher frequencies can be coded.

What determines our perceptual set?

through experiences we form schemas

what are the parts of the inner ear?

-cochlea -semicircular canals -vestibular sacs

What are the parts of the middle ear (3 tiny bones)?

-hammer -anvil -stirrup

What is tonic pain?

-long-lasting "chronic" pain after phasic pain ceases -slow pathway -serves to "remind" you of the immediate past and should thus assist you to learn to avoid the painful stimulus in the future

What is phasic pain?

-pain we feel immediately upon intense stimulation -rapid pathway -role is protective -interrupts processing of other information, causes you to switch attention -goal: take action, to remove you from the source of painful stimulus

How are action potentials in a "pain" nerve any different from those that correspond to light touch?

-sensory modality is coded by the specific nerve that carries the neuronal message -this is called Muller's "specificity" -the auditory nerve codes an auditory signal; the optic nerve, visual signals.

What are the 3 layers of the retina?

-the rods and cones -the bipolar cells -the ganglion cells

How do we localize sound?

-time difference between arrival of the sounds Ex.: a sound occurring on the left side will arrive at the left ear before it arrives at the right ear -intensity different between the ears Ex.: a sound occurring on the left side will be louder in the left than it is in the right ear, the head will actually block and attenuate the intensity of the sound being transmitted in the right ear (sound shadow)

In all modalities, what are the 5 critical features of the physical characteristics of a stimulus?

1. its modality (what type of experience is bombarding the receptor?) 2. its frequency 3. its intensity 4. its location 5. its duration

What is the rapid sequence of events that occurs when you see and recognize a friend?

1. light waves reflect off the person and travel into your eye 2.Retinal processing: receptor cells in you retina convert the lights waves' energy into neural impulses sent to your brain 3. feature detection: brain detector cells respond to specific features depth, movement, form 4.Parrelel processing: brain cell teams up information about colour, movement, form and depth at once 5. Recognition: it interprets this information based on previously stored information and you expectations into the conscious perception of your friend

How do we smell?

1. odorants bind to receptors 2. olfactory receptor cells are activated and send electric signals 3.the signals are relayed via converged axons 4. the signals are transmitted to higher regions of the brain

What are the basic steps in transforming sound waves into perceived sound?

1. the outer ear: collects the sound waves 2. the middle ear: translates into mechanical waves 3. the inner ear: turns it into fluid waves 4. the auditory nerve: translates the energy into electrical waves and sends it to the brain 5. the brain: perceives and interprets the sound

Why can some nocturnal animals have impressive night vision?

Because they have many more rods than cones in their retina

Why can cats see better at night?

Because they're able to open their pupils much wider which allows more light to enter their eyes

Does perceptual set involve a bottom-up or top-down processing and why?

It involves a top down processing. Our perceptual set influences our interpretation of stimuli based on our experiences, assumptions and expectations.

How do we sense our body's position?

Kinesthesis: the system for sensing the position and movement of individual body limbs -kinesthesis sensors all over the body

What is retinal disparity?

a binocular cue for perceiving depth: by comparing images from the retinas in two eyes, the brain computes distance--the greater the disparity (difference) between the two images, the closer the object

What is the basilar membrane?

a flexible membrane in the cochlea of the inner ear; the wavelike movement of this structure response to sound stimulates the receptor cells for hearing

What is the iris?

a ring of muscle tissue that forms the coloured portion of the eye around the pupil and controls the size of the pupil opening

What is perceptual set?

a set of mental tendencies and assumptions that greatly affects what we percieve

What is signal detecting theory?

a theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes that there is no signal absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness. -perceiving what is presented to our senses is subjective to each person

What is perceptual constancy?

allows us to perceive an object as unchanging even though the stimuli that fall onto our receptors have changed

What is Gestalt?

an organized whole. Gestalt psychologist emphasized our tendency to integrate pieces of information into meaningful wholes. "the whole may exceed the sum of its parts"

Why do we assume a car is large enough even if we see a tiny image of it from two blocks away?

because of size constancy, we perceive the car as having a constant size, this illustrates the close connection between perceived distance and perceived size

When a door opens, we still perceive it as a rectangle even though the angle is changing why?

because shape constancy allows us to perceive familiar objects as constant while our retinas receive changing images from them, our brain manages to associate different views of an object

How does information we see travel?

begins in the retina neural layers where is gets processed by receptor rods and cones, information travels to your bipolar cells, then to your ganglion cells, and then through their axons to the optic nerve of your brain, then any given retinal area relays its information to a corresponding location in the visual cortex, in the occipital lobe at the back of your brain

Define subliminal

below one's absolute threshold for conscious awareness

What is conduction hearing loss?

caused by damage to the mechanical system that conducts sound waves to the cochlea -a hearing aid (essentially an amplifier) can be used to improve hearing following conductive hearing lose

Where is the middle ear?

chamber between the eardrum and the cochlea

what is the coiled, bony, fluid-filled tube in the inner ear?

cochlea

What is a cochlear implant?

consists of a microphone, a processor, a transmitter and receiver/ stimulator, which receives signals from the speech processor and convert them into electric impulses

Light enters the eye through the _________ which protects the eye and bends light to provide focus

cornea

The experience (consciousness) of the perception of a stimulus almost always requires the ________?

cortex -a visual stimulus is experienced as light not because the visual receptors of the eye are stimulated but because the visual cortex has been stimulated.

What is sorineural hearing loss (nerve deafness)?

damage to the cochlea's hair cell receptors and their associated nerves -hearing aid cannot be used if the cochlea is extensively damages, a cochlear implant is necessary

What are binocular cues?

depth cues, such as retinal disparity that depend on the use of two eyes

What is sensory adaptation?

diminished sensitivity as a consequence of constant stimulation Ex.: constantly exposed to a certain odour, you become unaware of it

In terms of perception, a band's lead singer would be considered _________ (figure/ground), and the other musicians would be considered _________(figure/ground).

figure; ground

What theory of pitch perception would best explain about how we hear the low-pitched cello?

frequency theory, which presumes the the brain reads pitch by monitoring frequency of the neural impulses travelling up the auditory nerve (accounts for low-pitched)

How do we interpret loudness?

from the number of activated hair cells

What is top-down processing?

guided by higher-level-mental processes, constructs perceptions from the sensory input by drawing on our experience and expectations

What are monocular cues?

how we judge whether a person is 1 or 100 meters away; there isn't a difference between the left and right retina, we depend on the depth cues available to each eye separately

What is embodied cognition?

in psychological science, the influence of bodily sensations, gestures, and other states on cognitive preferences and judgements. Ex.: after holding a warm drink vs. a cold one, people are more likely to rate someone more warmly, feel closer

As long as stimulation is constant (remains the same), it is only necessary to perceive the _________?

initial onset

What type of pain (phasic or tonic) do we have much better memory for?

phasic, we remember the onset and the offset of pain much better than the long-lasting tonic pain

What theory of pitch perception would best explain a symphony audience's enjoyment of the high-pitched piccolo?

place theory, which presumes that we hear different pitches because different sound waves trigger activity at different places along the cochlea's basilar membrane (explains how we hear high-pitched sounds but not low-pitched)

What are the 4 touch receptors?

pressure, warmth, cold and pain

What are cones?

retinal receptor cells that are concentrated near the center of the retina and that function in daylight/well-lit conditions. Cones detect fine detail and give rise to colour sensations

What is priming?

the activation, often unconsciously, of certain associations thus predisposing one's perception, memory or response Ex.: the flashing of nude pic thing

What is the pupil?

the adjustable opening in the centre on the eye through which light enters

What is the process of accommodation?

the eye's lens changes shape to focus near or far objects on the retina

What determines the pitch of a sound?

the frequency of the sound waves

What influences the way we see brightness of a colour?

the intensity: the amount of energy in a light or sound wave as determined by the wave's amplitude

What is the retina?

the light-sensative inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

What is the difference threshold?

the minimum difference a person can detect between any two stimuli half the time

What is absolute thresholds?

the minimum stimulation necessary to detect a particular light, sound, pressure, taste or odour 50 percent of the time.

What is the optic nerve?

the nerve that carries neural impulses from the eye to the brain

What is the figure-ground organization?

the organization of the visual field into objects (the figures) that stand out from their surroundings (the groud)

What is grouping?

the perceptual tendency to organize stimuli into coherent groups

What is the blind spot?

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

What is sensory interaction?

the principle that one sense may influence another, as when the smell of food influences its taste

What is the opponent processing theory?

the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable colour vision. Ex.: some cells are stimulated by green and inhibited by red

What is the Young-Helmholtz trichromatic (three colour) theory?

the theory that the retina contains 3 different colour receptors: one most sensitive to red, one to green, one to blue, which, when stimulated in combination, can produce the perception of any colour

What is the gate-control theory?

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up the small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

What is the lens?

the transparent structure behind the pupil that changes shape to help focus images on the retina

What is the role of the sensory receptors?

to translate a very restricted amount of the earth's energy (that required for the survival of species) into something that the nervous system can understand, an electrical signal.

How do we sense our body's movement?

vestibular sense: movement of fluids in the inner ear caused by head/body movement -receptors are hairlike in the semi-circular canals and vestibular sacs

How does our system for sensing smell differ from our sensory for vision, touch, and taste?

we have 2 types of retinal receptors, 4 touch senses, 5 taste sensations, but we have no basic smell receptors. Instead, different combinations of odour receptors send messages to the brain, enabling us to recognize some 10,000 different smells.