Augenstein Jared Intro Psychology Chapter 3 Summary
VISION
Sensation o The awareness of properties of an object or event that occurs when a type of receptor (e.g. those in the ear, etc.) is stimulated o Sensations arise when enough physical energy strikes a sense organ, so that the receptor cells send neural impulses to the brain Perception o The act of organizing and interpreting sensory input as signaling a particular object or event o First must specify sizes and locations of objects, then recognize and identify Psychophysics o The study of the relation between physical events and the corresponding experience of those events Threshold o The point at which stimulation is strong enough to be noticed o Absolute threshold The smallest amount of a stimulus needed in order to detect that the stimulus is present o Just-noticeable difference (JND) The size of the difference in stimulus property needed for the observer to notice that a change has occurred A kind of threshold that depends on the overall magnitude of the stimulus (e.g. a thin person vs. a heavier person gaining 5 lbs.) Weber's law The rule that a constant percentage of a magnitude change is necessary to detect a difference (e.g. the greater the thickness of the waist, the greater the extra amount must be to be noticed) o Signal detection theory A theory explaining why people detect signals, which are always embedded in noise, in some situations but not others Sensitivity o The threshold level for distinguishing between a stimulus and noise the lower the threshold the greater the sensitivity Bias o A person's willingness to report noticing a stimulus
o Change bias by adjusting criterion Amplitude o The height of the peaks in a light wave Frequency o The rate at which light waves move past a given point Wavelength o The time between the arrival of peaks of a light wave; shorter wavelengths correspond to higher frequencies o Lower frequencies (longer wavelengths) are towards red end of spectrum, higher frequencies (shorter wavelengths) are towards violet end Transduction o The process whereby physical energy is converted by a sensory neuron into neural impulses Pupil o The opening in the eye through which light passes Iris o The circular muscle that adjusts the size of the pupil Cornea o The transparent covering over the eye, which serves party to focus the light onto the back of the eye Accommodation o Occurs when muscles adjust the shape of the lens so that it focuses light on the retina from objects at different distances Retina o A sheet of tissue at the back of the eye containing cells that convert light to neural impulses Fovea o The small, central region of the retina with the highest density of cones and the highest resolution Rods o Retinal cells that are very sensitive to light but register only shades of grey Cones o Retinal cells that respond most strongly to one of three wavelengths of light and that play a key role in producing color vision Optic nerve o The large bundle of nerve fibers carrying impulses from the retina into the brain o "Blind spot" because there are no rods/cones at the place where the optic nerve exits the retina Dark adaptation o The process whereby exposure to darkness causes the eyes to become more sensitive, allowing for better vision in the dark Circadian behavior
o Behavior that follows the daily pattern of light (e.g. waking/sleeping) Melatonin Ganglion cells Hue the aspect of color (whether it looks red, blue, etc.) determined by the present wavelengths of light Saturation how deep the color appears based on the purity of the input (the amount of white mixed in with the color) Lightness/brightness of color determined by amplitude of light waves Trichromatic theory of color vision o The theory that color vision arises from the combinations of neural impulses from three different kinds of sensors, each of which responds maximally to a different wavelength Eye contains 3 kinds of color sensors (long, medium, short) and brain registers color by combining responses to separate wavelengths Human perception of hues occurs as result of having 3 kinds of cones o One most responsive to light in wavelength perceived as yellow, one to green, and one to violet o Brain responds to mixture of these 3 response signals, not individual Colors perceived are the ones being reflected (whatever is not being absorbed) Opponent process theory of color vision o The theory that the presence of one color of a pair (red/green, yellow/blue, black/white) it causes cells that register it to inhibit the perception of the other (complementary) color Afterimage o The image left behind by a previous perception o Occurs when one member of a pair of opponent cells inhibits the other (e.g. green inhibits red) and then releases it Opponent cells o Cells that pit the colors in a pair, most notably blue/yellow or red/green, against each other o Cones feed into opponent cells located in retina and thalamus Color blindness o An inability, either acquired (by brain damage) or inherited, to perceive hue o Acquired achromotopsia acquired colorblindness Figure o In perception, a set of characteristics (such as shape, color, texture) that corresponds to an object Ground o In perception, the background, which must be distinguished in order to pick out figures
Camouflage when figure and ground are similar Brain's ability to delineate edges: o Neurons in the primary visual cortex (the first part of the cortex to process visual input, in the occipital lobe) are arranged in columns o Neurons in each column fire selectively to edges that have a specific orientation o Columns are arranged into sets driven by input from one of the eyes o Sets arranged into a hypercolumn o Neurons in each hypercolumn respond to input from single spot on retina o Hypercolumns are topographically organized, so pattern on retina is spatially laid out on cortex Gestalt laws of organization o Proximity marks near each other tend to be grouped together o Continuity marks that tend to fall along a smooth curve or straight line tend to be grouped together o Similarity marks that look alike tend to be grouped together o Closure tendency to close any gaps in a figure o Good form marks that form a single shape tend to be grouped together Perceptual constancy o The perception of characteristics that occurs when an object or quality (such as shape or color) looks the same even though the sensory information striking the eyes changes o E.g. size constancy Seeing an object as being the same size when viewed at different distances o E.g. shape constancy Seeing objects as having the shame shape even when the image on the retina changes o E.g. color constancy Seeing objects as having the same color in different viewing situations Binocular cues o Cues to the distance of an object that arise from both eyes working together Retinal disparity o The difference between the images striking the retinas of the two eyes o Brain uses amount of disparity to determine which objects are in front of and which are behind others Monocular static cues o Information that specifies the distance of an object that can be picked up with one eye without the movement of the object or eye o E.g. texture gradient Progressive changes in texture that signify distance
o E.g. in art, linear perspective, foreshortening, and occlusion cues used to indicate relative Motion distance cues o Information that specifies the distance of an object on the basis of its movement Visual pathways o "where" pathway goes up to the parietal lobes, concerned with spatial properties o "what" pathway goes down to the temporal lobes, concerned with properties of objects Object recognition vs. identification "Where" pathway Bottom-up processing o Processing of perceptions initiated by stimulus input Top-down processing o Perception processing that is guided by knowledge, expectation, or belief Perceptual set o The sum of your assumptions and beliefs that lead you to expect to perceive certain objects or characteristics in particular contexts (e.g. seeing the bottom light on a stoplight as green even if it is blue-green) o Perceptual expectancies perceptions dependent on your previous experiences "What" pathway Brain uses two ways to code space: o Categorical spatial relations code positions with categories such as "above" or "left of" or "inside" o Coordinate spatial relations specify continuous distance from your body or another object that serves as an "origin" of a coordinate space Attention o The act of focusing on particular information, which allows it to be processed more fully than what is not attended to Selective attention o The process of picking out a particular quality, object, or event for relatively detailed analysis Why we pay attention: o Pop-out Phenomenon that occurs when a stimulus is sufficiently different from the ones around it that it is immediately evident o Vigilance the act of actively anticipating a particular event thus causing you to maintain attention as you wait for it Blindsight
o When some visual function persists even when areas crucial for consciousness are damaged, because multiple pathways from the eye lead to many places in the brain, and some can function even though they do not pass through brain areas that give rise to conscious experience Repetition blindness o The inability to see the second occurrence of a stimulus that appears twice in succession Attentional blink o A rebound period in which a person cannot pay attention to one thing after having just paid attention to another Hearing Auditory Sensation: If a Tree Falls but Nobody Hears It, Is There a Sound? Sound Waves: Being Pressured Pitch- How high or low a sound seems; higher frequencies of pressure waves produce the experience of higher pitches. Loudness- The strength of a sound; pressure waves with greater amplitude produce the experience of louder sound. Like vision, auditory processing occurs in two major phases: sensation and perception If a tree falls in the forest but nobody hears it is there a sound? No, sound is caused by waves of molecules, but the waves themselves are not sound. Sound is a psychological event and hence depends on a nervous system to transduce the physical energy of the vibrations to nerve energy. The Brain's Ear: More Than a Microphone Hair Cells- The cells with stiff hairs along the basilar membrane of the inner ear that, when moved, produce nerve impulses that are sent to the brain; these cells are the auditory equivalent of rods and cones. Frequency Theory- The theory that higher frequencies produce higher rates of neural firing. Place Theory- The theory that different frequencies activate different places along the basilar membrane. Anatomy of the Ear- There are three parts, the outer ear, middle ear, and inner ear. The semicircular canals have no role in hearing; they help us keep our balance If you hear a loud sound, the muscles in you're ear reflexively tighten which protects against damage. Deafness: Hear Today, Gone Tomorrow Nerve Deafness- A type of deafness that typically occurs when the hair cells are destroyed by loud sounds. (Ex. Rock Concert) Conduction Deafness- A type of deafness caused by a physical impairment of the external or middle ear.
First Steps of Auditory Perception: Organizing the Auditory World Sorting Out Sounds: From One, Many Speech segmentation problem- The problem of organizing a continuous stream of speech into separate parts that correspond to individual words. Categorical perception- Identifying sounds as belonging to distinct categories that correspond to the basic units of speech. To organize sounds, we use auditory scene analysis. Locating Sounds: Why Two Ears Are Better Than One Since our heads block sounds, differences in loudness between the two ears are what we use to locate sounds. Turning our head allows us to compare the relative volume of a sound, to help locate its source. Auditory Perception: Recognition and Identification More Than Meets the Ear The phonemic restoration effect occurs when part of a word is missing in a sentence, the part is filled-in subconsciously. Hearing Without Awareness Cocktail party phenomenon- The effect of not being aware of other people's conversations until your name is mentioned, and then suddenly hearing it. Dichotic listening- A procedure in which participants hear stimuli presented separately to the two ears (through headphones) and are instructed to listen only to sounds presented to one ear. Smell: A Nose for News? Chemical Senses- Taste and smell, which rely on sensing the presence of specific chemicals. Women are better at sensing things than men, especially during ovulation. Distinguishing Odors: Lock and Key Odor detection is best described using the lock-and-key metaphor. Molecules have different shapes, and the olfactory receptors are built so that only molecules with particular shapes will fit in particular places. Pheromones: Another Kind of Scents? Pheromones- Chemicals that function like hormones but are released outside the body (in urine and sweat) Taste: The Mouth Has It Taste buds- Microscopic structures on the bumps on the tongue surface, at the back of the throat, and inside the cheeks; the four types of taste buds are sensitive
to sweet, sour, salty, and bitter tastes. All tastes are broken up into a combination of these four tastes. Taste and Smell What we taste is mostly what we smell, or a combination of both. Somasthetic Senses: Not Just Skin Deep Somasthetic Sense- Senses that have to do with perceiving the body and its position in space- specifically, kinesthetic sense, vestibular sense, touch, temperature sensitivity, pain sense, and possibly magnetic sense. Kineesthetic sense- The sense that registers the movement and position of the limbs. Vestibular sense- The sense that provides information about the body's orientation relative to gravity. Paradoxical cold- Occurs when stimulation of nerves by something hot produces the sensation of cold. Double Pain- The sensation that occurs when an injury first causes a sharp pain, and later a dull pain; the two kinds of pain arise from different fibers sending their messages at different speeds. Endorphins- Painkilling chemicals produced naturally in the brain Gate control of pain- The top-down inhibition of interneurons that regulate the input of pain signals to the brain Other Senses Magnetic Sense: Only for the Birds We may have a weak sense of magnets, birds migrate by using magnetic sense Extrasensory Perception (ESP) The ability to perceive and know things without using the ordinary senses. Ex. Telepathy, psychokinesis, precognition (the ability to foretell the future)