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121 Cards in this Set
- Front
- Back
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Synesthesia
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– the perceptual experience of one sense that is evoked by another sense
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Sensation
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– simple awareness due to the stimulation of a sense organ
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Perception
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– the organization, identification, and interpretation of a sensation in order to form a mental representation
-brain is perceptual organ -Sensation and perception are related – but separate – events |
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Transduction
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what takes place when many sensors in the body convert physical signals from the environment into neural signals sent to the central nervous system
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Psychophysics
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– methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus
-Gustav Fechner -measured stimulus to an observer’s yes-or-no response begins operationalizing sense perception |
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Thresholds
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-Begin by measuring a single sensory signal to determine how much physical energy is required to evoke a sensation in an observer
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Absolute Threshold
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-Minimal Intensity needed to just barely detect stimulus
-Typically defined as the intensity (e.g., brightness) required for a person to say she or he has perceived the stimulus on 50% of the trials -boundary between awareness and unawareness |
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Just Noticeable Difference (JND)
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-the minimal change in a stimulus that can just barely be detected
-Compare a standard (S), or fixed intensity stimulus, to other intensities of the stimulus |
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Weber’s Law
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– the just noticeable difference of a stimulus is a constant proportion despite variations in intensity
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noise
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refers to all of the other stimuli coming from the internal and external environment
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Signal Detection Theory
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an observation that the response to a stimulus depends both on a person’s sensitivity to the stimulus in the presence of noise and on a person’s response criterion
-observer consders stimulus before response - low fuzzy sensations a harder to bring impact awareness -sensory evidence - Theory proposes a way to measure perceptual sensitivity – how effectively the perceptual system represents sensory events – separately from the observer’s decision-making strategy |
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Liberal criteria vs Conservative criteria
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-Liberal criteria produce lots of hits and false alarms
-Conservative criteria reduce false alarms and increase misses |
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Sensory Adaptation
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– sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions
-familiarizing yourself with enviroment |
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Visual Acuity
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– the ability to see fine detail
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Snellen chart
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- used to measure visual acuity, where normal vision is reported as 20/20, or the ability to read line #8 at a distance of 20 feet from the chart
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Visible light
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the portion of the electromagnetic spectrum that humans can see (measured in nanometers, or billionths of a meter, between waves)
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Hue
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- color
-determined by the length of a light wave |
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Brightness
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-intensity
-determined by the amplitude (height) of a light wave |
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Purity
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-saturation (color richness)
-the number of wavelengths (frequency) that make up the light |
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Cornea
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– clear, smooth outer tissue of the eye that slightly bends light
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Pupil
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– a hole in the colored part (iris) of the eye
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Iris
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– translucent, doughnut-shaped muscle that controls the size of the pupil and hence the amount of light entering the rest of the eye
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Lens
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clear, double-convex structure that focuses light onto the retina
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Retina
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– light sensitive tissue lining the back of the eyeball
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Accommodation
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the process by which the eye maintains a clear image on the retina
-ex lens changing to to focus light on obhects at different distances |
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Light adaptation vs Dark adaptation
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vision adjusting low to bright, vice versa
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Photoreceptor Cells
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-on retina
-light sensitive pigments that transduce light into neural impulses -two types rods and cones |
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Cones
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-photoreceptors that detect color, operate under normal daylight conditions, and allow us to focus on fine detail
-6 million per retina, mostly in the fovea - 8 minutes to adapt |
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Rods
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– photoreceptors that become active only under low-light conditions for night vision
-approximately 120 million per retina, distributed around the retina -except in the fovea -30 mins to adapt to low light conditions -periph vision blurry b/c detected by rods |
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Fovea
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an area of the retina where vision is the clearest and there are no rods at all
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Retinal layers
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Retina contains three layers of cells
i. Rods and cones are in the innermost layer, receiving from bipolar cells, and sending signals to the middle layer ii. Bipolar cells are in the middle layer, receiving from rods and cones, and sending signals to the outer layer iii. Retinal Ganglion Cells (RGCs) are in the outer layer, receiving from bipolar cells, and sending signals to the brain via the optic nerve (a) Blind Spot – a hole in the retina that contains no rods or cones where the optic nerve leaves the retina; therefore it has no mechanism to detect light |
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Receptive Fields
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– the region of the sensory surface that, when stimulated, causes a change in the firing rate of that neuron
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Lateral Inhibition
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– opposing responses of neighboring photoreceptors interacting to result in the signals sent to the bipolar cells, then on to the RGCs
-opposing meaning that the signals through the bipolar cells to the retinal ganglion cells are based on differing level of nueron activation -Allows the detection of edges to define boundaries and shapes of objects (render the permiter of things) |
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RGC shape in receptive fields..
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Most receptive fields that represent an RGC contain either a central excitatory zone surrounded by a doughnut-shaped inhibitory zone (on-center cell) or a central inhibitory zone surrounded by a doughnut-shaped excitatory zone (off-center cell)
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Use of RGC in receptive field...
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kind of “spot detector” encoding differences in brightness or color by recording differences in excitation and inhibition of receptive fields
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Evolutionary reason for color...
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fundamental clues to an object’s identity and whether or not to be alarmed
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Wavelength shortest to longest...
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The shortest wavelengths of visible color are deep purple, then blue, green, yellow, orange, and the longest waves are seen as red
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Rods and photopigment
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rods contain only one type of photopigment, cones can contain one of three photopigments sensitive to Red (Long-wavelength; L-cones), Green (Medium-wavelength; M-cones), or Blue (Short-wavelength; S-cones) that are the primary colors of light
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Additive Color Mixing
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– increasing light to create color (e.g., combine red and green spotlights to create yellow light)
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White
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White is the reflection of all colors (or lights)
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Subtractive Color Mixing
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removing light from the mix (e.g., combine yellow and red paints to create orange paint)
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Black
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Black is the reflection of no color (or light)
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Trichromatic Color Representation in the Cones
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– the pattern of responding across the three types of cones that provides a unique code for each color
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Color-Opponent Representation into the Brain
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Cones can fatigue if you stare at one color for too long, resulting in a form of sensory adaptation called color afterimage
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Color-Opponent System
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– pairs of visual neurons that work in opposition (red vs. green and blue vs. yellow)
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Trichromatic and color-opponent systems begin color perception
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S-, M-, and L-cones connect to color-opponent RGCs that send excitatory-inhibitory information down the optic nerve to the thalamus, and then to the occipital cortex
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Visual Brain 1
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Half of the axons in the optic nerve that leave each eye come from the RGCs representing the left visual field, whereas the other half come from the RGCs representing the right visual field
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Visual Brain 2
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The optic nerve from each eye travels to the lateral geniculate nucleus (LGN) of the thalamus
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Visual Brain 3
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The information leaves the thalamus and travels to the primary visual cortex (V1) in the occipital lobe
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V1
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-percieving shape
-occipital lobe -specialized for detecting the location and orientation of edges -i. There are cells to detect vertical edges, horizontal edges, 45° edges, and everything in between |
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Pathways for visual streams
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-ventral stream, or “what pathway,” projects to the lower levels of the temporal lobes and represents an object’s shape and identity
(towads temporal lobe) -dorsal stream, or “where pathway,” projects to the parietal lobes and dorsal temporal lobes and identifies the location and motion of an object (frontal lobe) -dorsal stream the “how pathway” because of its role in aiming, reaching, and tracking faces ventral location/aim dorsal |
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Visual-Form Agnosia
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the inability to recognize objects by sight
vental/temporal lobe |
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Optic Ataxia
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difficulty using vision to guide reaching and grasping movements
Dorsal parietal frontal |
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Modular View
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specialized brain areas, or modules, detect and represent faces or houses or even body parts
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Distributed Representation
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the pattern of activity across multiple brain regions that identifies any viewed object, including faces
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Perceptual Constancy
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– a perceptual principle stating that even as aspects of sensory signals change, perception remains consistent
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Gestalt perceptual grouping rules
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(a) Simplicity (Pragnanz) – when confronted with two or more possible interpretations of an object’s shape, the visual system tends to select the simplest or most likely interpretation
(b) Closure – we tend to fill in missing elements of a scene, allowing us to perceive edges that are separated by gaps as belonging to complete objects (c) Continuity – edges that have the same orientation tend to group together perceptually (d) Similarity – regions that are similar in color, lightness, or texture are perceived as belonging to the same object (e) Proximity – objects that are close together tend to be grouped together (f) Common Fate – elements of a visual image that move together are perceived as parts of a single moving object |
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Before recognition can occur.......
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erceptual system must group the image regions that belong together into a representation of an object
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Separating Figure from Ground
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i. Size: smaller regions are likely to be figures
ii. Movement: figures tend to move more than their surroundings iii. Edge Assignment: identifying whether an edge belongs to the figure or the ground |
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Image-based object recognition theories
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state that an image seen previously is stored in memory as a template, then compared to the current image for recognition purposes
Problems (a) You would need multiple templates for different orientations of an object (b) Doesn’t account for things you’ve never seen before |
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Template
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– a mental representation that can be directly compared to a viewed shape in the retinal image
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Parts-based object recognition theories
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that the brain deconstructs viewed objects into a collection of parts, stored as structural descriptions or mental inventories, that act as sort of an “alphabet” of geometric elements (called geons) that can be combined to make objects
i. Problems (a) Only allows for recognition at the level of categories, not individual objects (e.g., explains recognizing a face, but not Grandma’s face) |
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How does the 2 dinmensional retina present three dimensional image...?
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i. Three dimensions are represented on the retina through depth cues (monocular, binocular, and motion-based) that change as you move through space
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Monocular Depth Cues
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-one eye
-i. Relative Size – the retinal image of an object you’re focused on grows smaller as that object moves farther away, and larger as it moves closer ii. Familiar Size – many common objects (e.g., adult people) fall within a familiar range of heights (i.e., 5-7 feet tall), so the retinal image size alone is usually a reliable cue for distance iii. Linear Perspective – phenomenon that parallel lines seem to converge as they recede into the distance iv. Texture Gradient – when viewing a uniform pattern, the size of the pattern elements, as well as the distance between them, grows smaller as the surface recedes from the observer v. Interposition – when one object partially blocks another object, the one doing the blocking is usually closer than the one being blocked vi. Relative Height in the Image – objects that are lower in your field of vision are closer to you, whereas higher objects are farther away |
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Binocular Depth Cues
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a. Stereoscopic Vision – having space between our eyes means that each eye registers a slightly different view of the world
b. Binocular Disparity – the difference in the retinal images of the two eyes that provides information about depth 2 angles contrive better world view |
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Motion-Based Depth Cues
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Motion Parallax – a depth cue based on the movement of the head over time (i.e., when moving, far away objects don’t tend to move much whereas closer objects move by quickly)
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Optic Flow
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– the pattern of motion that accompanies an observer’s forward movement through a scene (a type of motion parallax)
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Ames Room
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– a trapezoidal room that makes two identically-sized people appear to be grossly different in size based on the room cues when viewed with one eye
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Moon Illusion
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– the full moon appears larger when it is at the horizon than high in the sky, because other objects (hills, trees, etc.) intervene between the moon and the viewer
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Perceiving Motion
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a. Neural circuits detect changes in the stimulation location on the retina of an object (as it moves through a stationary visual field) as different speeds and directions of motion
b. The brain also detects your head and eye movements and subtracts those movements from the motion of the retinal image when you are moving |
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Waterfall Illusion
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if motion sensitive neurons are fatigued through adaptation the opposing sensor will take over ...similiar to color afirmage
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Apparent Motion
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the perception of movement as a result of aternating signals appearing in rapid succession in different locations
Motion picture sampling rate is 24 frames per second (fps) to reproduce the continuous motion of the original scene |
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How can hearing be measured...?
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– changes in air pressure unfolding over time
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Pure Tone
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– a simple sound wave that first increases air pressure and then creates a relative vacuum
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Pitch
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(high or low) is determined by the frequency (wavelength) of the sound wave, measured in cycles per second, or hertz (Hz)
a. Changes in frequency over time allow for the identification of the origin of the sound |
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Loudness
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sound intensity) is determined by the amplitude (height) of the sound wave, measured in decibels (dBs)
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Timbre
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(sound quality or resonance) is determined by the complexity of the sound waves, or their mix of frequencies
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Outer Ear
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3 parts Pinna (visible part) Auditory Canal, Ear Drum (air tight flap of skin taht viberates in response to sound waves)
-collects sound waves and funnels them toward the middle ear |
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Middle Ear
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transmits vibrations to the inner ear
Contains three tiny bones, or ossicles (hammer, anvil, and stirrup) that form a lever for transmitting and intensifying vibrations from the eardrum |
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Inner Ear
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embedded in the skull, transduces vibrations into neural impulses
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Cochlea
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– a fluid-filled tube that is the organ of auditory transduction
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Basilar Membrane
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– a structure in the inner ear that undulates when vibrations from the ossicles reach the cochlear fluid
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Hair Cells
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specialized auditory receptor neurons embedded in the basilar membrane, causing the release of neurotransmitter, initiating a neural signal in the auditory nerve that goes to the brain
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Area A1
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portion of the temporal lobe that contains the primary auditory cortex
-Left hemisphere language -right hemisphere rythmic sounds and music -topographically resonds to sounds |
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Place Code
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the cochlea encodes different frequencies at different locations along the basilar membrane
high freqs |
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Temporal Code
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the cochlea registers low frequencies via the firing rate of action potentials entering the auditory nerve
measures amount of base instead of place on basilar membrance |
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Localizing Sound sources
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placement of our ears on the opposite sides of the head gives us stereophonic
hearing similar to what gives us depth |
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Somatosenses
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or body senses, are for detecting things close to our bodies
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Haptic Perception
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– the active exploration of the environment by touching and grasping objects with our hands
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Four receptors
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provide a rich tactile experience by sensing pressure, texture, pattern, or vibrations
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touch vs visual receptive fields
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Touch receptors have receptive fields much like visual receptive fields, with excitatory centers and inhibitory surrounds
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Neural representation of the body’s surface
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There is contralateral organization
More of the tactile brain is devoted to parts of the skin surface that have greater spatial resolution (e.g., fingertips and lips) |
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Pain
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indicates damage or potential damage to the body
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Tissue damage
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transduced by pain receptors
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Perceptual Constancy
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– a perceptual principle stating that even as aspects of sensory signals change, perception remains consistent
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Gestalt perceptual grouping rules
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(a) Simplicity (Pragnanz) – when confronted with two or more possible interpretations of an object’s shape, the visual system tends to select the simplest or most likely interpretation
(b) Closure – we tend to fill in missing elements of a scene, allowing us to perceive edges that are separated by gaps as belonging to complete objects (c) Continuity – edges that have the same orientation tend to group together perceptually (d) Similarity – regions that are similar in color, lightness, or texture are perceived as belonging to the same object (e) Proximity – objects that are close together tend to be grouped together (f) Common Fate – elements of a visual image that move together are perceived as parts of a single moving object |
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Before recognition can occur.......
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erceptual system must group the image regions that belong together into a representation of an object
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Separating Figure from Ground
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i. Size: smaller regions are likely to be figures
ii. Movement: figures tend to move more than their surroundings iii. Edge Assignment: identifying whether an edge belongs to the figure or the ground |
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Image-based object recognition theories
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state that an image seen previously is stored in memory as a template, then compared to the current image for recognition purposes
Problems (a) You would need multiple templates for different orientations of an object (b) Doesn’t account for things you’ve never seen before |
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Template
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– a mental representation that can be directly compared to a viewed shape in the retinal image
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Parts-based object recognition theories
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that the brain deconstructs viewed objects into a collection of parts, stored as structural descriptions or mental inventories, that act as sort of an “alphabet” of geometric elements (called geons) that can be combined to make objects
i. Problems (a) Only allows for recognition at the level of categories, not individual objects (e.g., explains recognizing a face, but not Grandma’s face) |
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How does the 2 dinmensional retina present three dimensional image...?
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i. Three dimensions are represented on the retina through depth cues (monocular, binocular, and motion-based) that change as you move through space
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Monocular Depth Cues
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-one eye
-i. Relative Size – the retinal image of an object you’re focused on grows smaller as that object moves farther away, and larger as it moves closer ii. Familiar Size – many common objects (e.g., adult people) fall within a familiar range of heights (i.e., 5-7 feet tall), so the retinal image size alone is usually a reliable cue for distance iii. Linear Perspective – phenomenon that parallel lines seem to converge as they recede into the distance iv. Texture Gradient – when viewing a uniform pattern, the size of the pattern elements, as well as the distance between them, grows smaller as the surface recedes from the observer v. Interposition – when one object partially blocks another object, the one doing the blocking is usually closer than the one being blocked vi. Relative Height in the Image – objects that are lower in your field of vision are closer to you, whereas higher objects are farther away |
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Binocular Depth Cues
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a. Stereoscopic Vision – having space between our eyes means that each eye registers a slightly different view of the world
b. Binocular Disparity – the difference in the retinal images of the two eyes that provides information about depth 2 angles contrive better world view |
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Tissue damage
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i. A-delta fibers – transmit the initial sharp pain from sudden injury
ii. C-fibers – transmit the longer-lasting, duller pain that persists after the initial injury |
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Two pain pathways
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i. Somatosensory cortex identifies where the pain is occurring and what sort of pain it is (sharp, burning, dull)
ii. Motivational and emotional areas (amygdala, hypothalamus, frontal cortex) to motivate the escape from the source of the pain |
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Referred Pain
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– feeling of pain when sensory information from internal and external areas converge on the same nerve cells in the spinal cord
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Gate-Control Theory
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– a theory of pain perception based on the idea that signals arriving from pain receptors in the body can be stopped, or gated, by interneurons in the spinal cord via feedback from two directions
(c) Bottom-up control – senses feed information to the brain (d) Top-down control – brain exerts control over what we sense |
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Vestibular System
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the three fluid-filled semicircular canals and adjacent organs located next to the cochlea in each inner ear
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gustation
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taste
respond to the molecular structure of substances dissolving in saliva (as you ingest) |
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olfaction
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smell
respond to the molecular structure of substances floating in the nasal cavity (as you inhale) |
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Olfactory signals
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sent directly to the frontal lobe, amygdala, and other parts of the forebrain without stopping at the thalamus first
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olfactory epithelium
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Odorant molecules released from substances travel through the air into our noses and interact with olfactory receptor neurons (ORNs) in the olfactory epithelium situated on top of the nasal cavity, sending action potentials down the olfactory nerve
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Olfactory Receptor Neurons
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– receptor cells that initiate the sense of smell
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Olfactory Bulb
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– a brain structure located above the nasal cavity and beneath the frontal lobes
i. Glomerulus – a site where ORNs converge in the olfactory bulb to begin perception of odorants |
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Pheromones
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– biochemical odorants emitted by other members of a species that can affect an animal’s behavior or physiology
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Taste
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1. A primary function of taste is to identify things that are poisonous and lethal
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Tongue
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is covered in papillae, or small bumps, with each one containing hundreds of taste buds
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Taste Bud
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the organ of taste transduction
approximately 5,000 to 10,000 cover the tongue, roof of the mouth, and upper throat ii. Each bud contains 50 to 100 taste receptor cells Tips of receptors, called microvilli, react with tastant molecules in food |
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Five main types of taste receptors
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salt (NaCl), sour (acids), bitter, sweet, and umami (savory; responding to high protein and MSG)
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Taste and smell collaborate
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complex perception of flavor
a. Odorants from substances outside the mouth enter the nasal cavity via the nostrils, and odorants in the mouth enter through the back of the throat |
