Psych Exam #2

Treisman and Gelade Experiment

1980 Reaction time: Feature search (one feature)-- constant time, does not depend on set size and search occurs in parallel (can search both at the same time if only looking for one particular feature) Conjunction search (two or more features)-- Response time increases linearly with set size (more objects with shapes and colors) and search occurs serially (search is done one after the other...rather than parallel)

Gustotopic

A gustotopic map of taste qualities in the mammalian brain in the primary taste cortex Used a mouse brain to find how bitter, salty, umami and sweet were spatially organized in the primary taste cortex

Cognition

A set of computations performed on representations

Current theorizing for auditory coding

Both frequency and place coding is used for all frequencies Place going is relied on more for high frequencies Frequency coding is relied on more for low frequencies

Sensation

Bringing information about the outside world to the brain (the raw data--old school camera) Sensation is mediated Sensation is limited

Transduction

Converting a stimulus into neuronal signals

Segmentation

Goal: Parse (analyze parts of the) objects in the stimulus Achieved by: Edge detection, determining figure-ground and grouping

Occlusion

Happens when near surfaces overlap far surfaces If one object partially blocks the view of another object, humans perceive it as closer Problem/challenge: This information only allows the observer to create a "ranking" of relative nearness Requires determination of object contours Ex.) The fact that in an image of a fruit bowl with a pitcher behind it...the fruit "occludes" the pitcher (aka, the pitcher is behind the fruit)

Cortical Geography

In principle, sensory information could be represented by very different locations in the brain Even limited to primary auditory cortex, frequencies could be represented anywhere (within that cortex)

Illusory Conjunctions

In rapid presentation, subjects will often mis-combine color and form (ex. presented with blue "S" and green "B"...but sometime subject reported green "S" or Blue "B") Indicates that features are processed independently and then combined

Sensation is Limited

It is limited because we can only perceive certain parts of energy-- ex.) For vision, there is a large scale of electromagnetic energy, but we can only sense part of it--this is called visible energy (The same goes for auditory sense with the range of Hz heard, etc)

Visual Attention

Necessary to "bind" features to the same item (form, color, etc) In visual search: Attention can only be deployed to one location at a time Conjunction search is slow, serial process because attention must be directed to successive locations to bind features in order to determine the location of the target

Role of attention in visual and spatial cognition

Necessary to bind features together (like red "A") Necessary to "inspect" internally generated spatial representations (like the square experiment from point A and B)

Determining Figure-ground

Next step in segmentation Trying to figure out what is object and what is environment? (Important point-- what we used to parse the stimulus in segmentation is in our heads, not in the world!) Ex.) In black, looks like a candle holder...and on each side are white faces....which do you perceive as object, and which is environment/ background?

Determining Location

Next step in visual perception after segmentation Can use binocular disparity, texture density gradient, light source/depth cues, and occlusion

Feature networks

Objects are recognized based on their component parts Detectors gather evidence from lower levels of organization Ex.) Feature detectors (curves, lines, etc) lead to letter detectors ("C", "K," etc) which then leads to a word

Short term memory vs. Working memory

Older theories: temporary store of information, step along the way to storage in LTM, passive storage, unitary store Current theories: temporary store of information, "buffer" for information used in processing, active storage, separate verbal and visual systems

Hermann Grid

Part of enhancing contrast in edge detection for segmentation Black squares increase the contrast of adjacent white regions (making them whiter) -- The corners don't have lateral inhibitory connections, leaving them unenhanced (= darker)

Somatotopy

Point-for-point correspondence of an area of the body to a specific point on the central nervous system The part of the body will correspond to a point in the somatosensory cortex Represented by a sensory homunculus map, which orients the specific body parts and their respective locations upon the homunculus The areas which are finely controlled (e.g., the digits and lips) have larger portions of the somatosensory cortex whereas areas which are coarsely controlled (e.g., the trunk/torso) have smaller portions (Somatosensation)

Sensory Organs

Receive energy from or are otherwise stimulated by the environment Eyes-- light energy Ears-- acoustic energy Skin--mechanical energy and heat Tongue-- molecular stimulation Nose-- molecular stimulation Inner ear, joints -- mechanical energy from stretching

Top-down vs. Bottom-up information

Top-down = knowledge Bottom-up = stimulus

Working memory

Used any time you manipulate information, not just used on first input

Articulatory Loop

Verbal information is maintained through a process of subvocalization and retention Phonological store (back and forth from) articulatory rehearsal) Information decays from the store-- in order to maintain it, one most "say it in one's head" -This actually involves sending it to the articulatory system (though one need not say it aloud)

Cognitive psychology

Views the mind/brain as an information processor

Sensation is mediated

We do not have direct perception of objects -- We receive information about objects indirectly (ex. through light, sound waves) This information is further affected by the properties of the sensory system

What is the object of visual attention?

1.) A location in space OR 2.) An object in space

Visual Perception

1.) Segmentation -- Finding object boundaries 2.) Local analysis -- Determining properties 3.) Normalization-- Abstracting

Atkinson-Shiffrin

1968 Said that short-term memory is unitary, temporary storage where information goes on its way to being stored It is a temporary storage location before information enters long-term memory

Bisiach and Luzzatti

1978 Asked patients with left unilateral neglect to describe the area they were standing in, in the square, from memory Either from position A (which faced the cathedral) or from position B (facing away from the cathedral) Results: When recalling locations from memory, patients only recalled those locations on the right side of space from their perspective (the patients knew the layout of the entire square, because they could recall locations when imagining from the other perspective) Spatial neglect can affect internally generated representations in addition to information coming from the outside world This means that we must attend to our own mental representations (attention is required to inspect our own spatial representations)

Tootell Experiment

1991 Used Metabolic Radio-Isotope Markers (glucose) in the brain to figure out the spatial organization of the visual cortex, done on a macaque monkey In this experiment by Roger Tootell, the target-shaped stimulus with radial lines was centered on an anesthetized macaque monkey's right visual field for 45 minutes after injection with radioactive 2-deoxyglucose. One eye was held closed. One picture (of the actual brain) shows the labeling in the striate cortex of the left hemisphere--This autoradiograph shows a section parallel to the surface; the cortex was flattened and frozen before sectioning The roughly vertical lines of label represent the (semi)circular stimulus lines; the horizontal lines of label represent the radial lines in the right visual field The hatching within each line of label is caused by only one eye having been stimulated and represents ocular-dominance columns

Behrmann Et Al. Experiment

1998 Task: Judge whether the number of bumps are the same (short presentation of objects with the bumps) Conditions: Bumps on the same object were in Row 1 and 3, and bumps on different objects were on Row 2 Results: Accuracy was better for same-object than different-object; True, even though bumps on same object were farther from each other than bumps on different object Due to the fact that if bumps are all on the same object, subjects are saved the need of shifting attention between objects

Opponent-Process Theory of Color

3 types of cones transduce light Color is then coded in terms of 3 antagonistic channels Red-green, Blue-yellow and Black-white Opponent/Antagonistic = Channel codes for only one at a time (Yellow, but not blue, etc) All colors are combination of yellow OR blue + red OR green 2 opponent channels: one will be stimulated and the other will be inhibited-- if for the blue-yellow channel, blue is stimulated, than yellow will be inhibited; if for the red-green channel, red is stimulated, green will be inhibited

Measuring Sensation

Absolute threshold, Just Noticeable Difference, Weber's Law

Retinotopic Organization

Adjacent points in space are processed by adjacent points in visual cortex Show in retinotopic map of the visual cortex with corresponding numbers from the visual field coming from the eye (center is the fovea)

Working memory systems

Alan Baddeley 2 working systems: Articulatory Loop and Visual-Spatial Sketchpad

Attention

Although the senses are constantly transcoding information from the environment, very little of it is fully processed or makes it to your awareness Attention is like a "spotlight" that we can direct various parts of our environment--proved wrong by inhibition of return (showed that attention does not facilitate anything in a particular space, but rather, it selects particular objects)

Edge Detection

An edge is a discontinuity in a physical surface This is the first step to extracting objects Edges can be identified by: enhancing contrast and finding lines Enhance contrast --will receive bright physical stimulus (intense stimulation) and gray physical stimulus (moderate stimulation) -- each will brought to a neuron and each neuron has a sideways connection that provides inhibition-- Due to position on a stimulus, one side may look brighter than the rest of the same stripe, and the other side may look darker, creating an "edge" (look at a piece of paper with different colors of black/white/grey scale segments) Lateral inhibition-- adjacent neurons inhibit each other (the visual system as well as other sensory systems contain lateral inhibition at many levels) to heighten contrast--competitive interaction to which field will be activated Ex.) Vision- have dark and light photoreceptors, and when stimulus hits light photoreceptors, lateral inhibition keeps the stimulus from also hitting the dark photoreceptors, thus enhancing the contrast between dark and light

Copying task

Another task used to test for unilateral spatial neglect Instructions: Copy each figure (ex. given a house, flower and clock) If lefts-sided neglect, will only draw the right half of the clock, house and flower (and vice-versa)

Is attention simply attenuation or does it play other roles in cognition?

Attention appears to be a critical component to visual perception, binding together visual features

Top-down processes in attention

Attention can be deployed strategically, based on one's goals (Watching a magician's hands, waiting for the light to turn green, listening to one individual in a crowded restaurant, watching a location for an enemy) This knowledge modulates what is salient (if something is expected based on the context, it won't be salient enough to attract your attention through bottom-up means)

Filtering theory

Broadbent (1958) The perceptual system has a fundamental capacity limitation Only one piece of information can be processed at a time Attention is a filter Shows that from sensory input, two things can go to attention, but only one thing will be processed further (example...to verbal processing)

Opponent Processes

Can code for all colors Can account for pairs of colors in after images Can account for lack of red-green, yellow-blue colors (ex. Moving green dot illusion-- absence of red = green) Back by neural evidence

Trichromatic theory

Coding of color (proposed before the 3 photopigments were known) Young and Helmholtz Observed: All colors can be made through a combination of Red, Green and Blue (RGB) Proposed: Color is coded as a combination of RGB Problems: The after images reveal pairs of colors (green leads to red and yellow leads to blue) We can have yellow-green, blue-green, yellow-red, reddish-blue, but NOT red-green or yellow-blue

The role of attention in early visual perception

Color and shape are processed independently in the visual system Ex.) Red "A" -- the color and the letter are processed independently

Experience

Constructed from the very way that sensory information is transducer and coded

Sensory receptors

Convert the received energy from the environment into neural signals which are sent to the brain

Weber's Law

Describes the relationship between intensity and a JND Rather than being constant, JNDs vary as a proportion of the intensity -- One cannot detect a different in weight between 200 and 210 grams, but 200 vs. 220 grams is detectable; thus, the change in intensity and the baseline (a minimum or starting point used for comparisons) intensity is constant States that the just noticeable difference between two stimuli is based on a proportion of the original stimulus rather than on a fixed amount of difference More intense the stimulus, the bigger the change needed for you to notice Example: Pick up 1 oz letter then 2 oz letter...can easily detect difference; pick up 5 lb package and a package weighing one more ounce...much harder to detect difference

Bottom-up processing

Detect features of the input (the feature detectors) which leads to figuring out letters and then these features combine into more complex forms (like words)

Perception's Goal: Audition

Determine words Identify speaker, localize in space Make contact with long term memory

Visual Attention

Different from fixation It is possible to attend to a point in space that one is not looking at Empirical demonstration of visual attention: Cued Detection Paradigm (Posner, 1980)-- Subjects maintain fixation (normally on a "plus sign" in the middle of visual field); on some trials, a cue is given regarding which side a stimulus will appear (cue is 80% accurate and appears in the form of an arrow pointing to the left or right); task: push a button when the stimulus is detected; results: correct cue- no cue = process benefit of attention and wrong cue- no cue = processing cost of attention (Showed that when given the wrong cue, the reaction time was far more than when given the right cue or even no cue as to where to focus attention to and push the button)

Perception's Goal: Vision

Differentiate objects Determine position, shape, motion, texture, etc. Make contact with information stored in long term memory

Binocular Disparity

Distance between the eyes causes the visual scene to appear slightly differently on the two retinas Ex.) Hold thumb over a certain point (with one eye closed)...then switch which eye is closed and you will see a slight shift in visual scene

Find lines

Each neuron responds to a point of the visual field (its 'receptive field')--so use On-center, Off-surround In On-center, off-surrond, cells of the neuron selectively fire when there is light in the center of their receptive field, and when a bank of on-center, off-surround cells are jointly firing, this indicated a line

Auditory attention

Empirical demonstration of auditory attention: Dichotic listening task (Cherry, 1953)-- Two auditory streams, one per ear; subjects asked to shadow one ear; subjects are able to report very little information from the unattended (unshadowed) ear

Phonological similarity effect

Evidence for the articulatory loop Sequences containing similar sounding items (C, G, B, D, P) are harder to store than sequences containing dissimilar items (X,K,T,S,N)

Articulatory Suppression Effect

Evidence for the articulatory loop Subjects who are forced to repeat a syllable have a much harder time storing/recalling sequences

Cocktail Party effect

Evidence in favor of attenuation Psychologist Cherry You can focus on a single conversation in the midst of a chaotic cocktail party A particularly pertinent stimulus (such as hearing your name mentioned in another conversation) can capture your attention You can then focus your attention on that conversation if you really want to hear it...and thus, lose the thread of your original conversation (won't be paying attention to the conversation at hand) Shadowing: Participants wear headphones that deliver one message to one ear and a different message to the other Person asked to attend to one of the two messages and "shadow" it by repeating it aloud Result—Will have noticed the unattended sound, but wont be able to recall the content; Shows subjects can switch ears when shadowing based on content of message Require processing auditory stimuli up through semantics

Herman Ebbinghaus

First to investigate memory experimentally Created a set of nonsense syllables (DAX, TELK, etc) Created a random sequences of syllables Examined how long it took to learn a sequence Examined how long it took to forget a sequence Found that: Learning is improved with repetition Longer items/lists take more receptions to learn Forgetting is a function of time Accuracy varies by position in list (serial position curve)--better at remembering if at beginning or end of list...not in the middle

Top-down processing

Formulate hypothesis about the identity of the stimulus (ex. thoughts about animal)...which leads to word detectors Then, select and examine relevant aspects of the stimulus to check the hypothesis (letters and feature detectors) Can make you hear sounds that aren't there Can make you see lines that aren't there Can guide the entire process of segmentation, analysis and normalization

Place theory

Frequency is encoded by the location of neuronal firing Different neurons in the inner ear code for different frequencies (each happen along a different part of the inner ear/basilar membrane inside the cochlea depending on if it is a low, medium or high-frequency sound) Problem: Low frequencies move the entire basilar membrane (not just coded for in the end)

Frequency theory

Frequency is encoded by the rate of neuronal firing Says: Neurons fire 1/cycle, so 100Hz Tone = 100 action potentials/sec Problem: Limited by refractory period of the axon; according to this...upper limit is 1000 Hz (maybe 4000)...but we can hear tones up to 20,000 Hz!

Auditory Coding

Frequency theory and Place theory

Gestalt Principles

Heuristics for organizing visual objects Done by: Similarity, proximity, good continuation, closure and simplicity But, sometimes these heuristics are wrong!

Phoneme restoration

How do we account for the fact that people often perceive an /s/ in LEGISLATURE, even when it has been removed and replaced with a noise (or cough?) The information isn't in the signal...so a strictly bottom-up account would predict that we don't hear the /s/ in these cases Trace: Hear an acoustic signal, which leads to a phoneme (/s/, /b/, /t/, etc) which then leads to lexical interpretation (the word at hand) If strictly bottom-up for "legislature," /s/ is not an input and there /s/ was not perceived Bottom-up and top-down together shows information can now flow from phonemes to words and words to phonemes Top-down knowledge of the word "legislature" allows us to perceive the phoneme /s/ even when it's masked with a noise (and therefore, not in the bottom-up input)

Grouping

Last step in segmentation How should parsed units be grouped? Heuristics-- a rule of thumb (ex. "When there's smoke, there's fire." - is this always true? NO, but is it useful? YES)

Normalization

Last step in visual perception after determining location Abstracting away from irrelevant surface properties in order to make contact with long-term memory Sound: Abstract away from male/female, young/old, healthy/sick, etc. to determine a word

Texture density gradient

Less density in the same texture indicates proximity Greater density indicated distance Ex.) A cobblestone road--more stones densely packed will be shown in the background...aka a greater distance Can also give size information -- ex.) Look at a dog sitting on a tile floor (if you zoom into the picture, the dog may appear larger, but in comparison to texture/density of the tile floor, you can tell the dog is the same size relative to the density)

Cones

Less sensitive to low levels of light Responsible primarily for vision under high illumination and for seeing both color (chromatic) and detail Found more in the center of retina (at the fovea) There are three types of photopigments for cones that transduce/code for short, medium and long wavelengths of color

Capacity of short-term memory

Miller (1956) -- "The Magical Number Seven, Plus or Minus Two" Subjects can accurately repeat a sequence of about 7 +/- 2 items (ex. phone numbers) Miller acknowledged that there is no magical number as working memory capacity is actually highly dependent upon factors such as age, type of item being remembered, etc

Unilateral Spatial Neglect

Most frequently results from damage to the parietal lobe Patients seems to be unaware of the contralateral half of space Symptoms: Failing to be aware of objects in one side of space, failing to dress one side of one's body and eating food from only one side of the plate Individuals with neglect cannot attend to portions of sensory information (in the moment, based on representations generated by senses) Individuals with neglect cannot attend to one side of any representation with spatial organization, even their own internally generated representations

Cortical Magnification

Not all of the sensory space is processed by equal amounts of cortex -Important areas of "sensory space" are processed by more cortex Ex.) Vision-- light hitting the fovea is represented by a large amount of cortex (but the farther from the fovea the light hits...the less amount of the cortex that visual input takes)

Perception

Not simply matching a stored example (requires active processing)

Line cancellation task

One task used to test for unilateral spatial neglect Instructions: Out of a full paper of lines, need to put a mark through each line (you see) on the page If all lines are marked, you do not have neglect If lines on the right side are marked but not the left side, you have left-sided neglect (and vice-versa)

Color Constancy

Part of normalization for vision Surface colors look very different in different types of light...so we need to interpret physically different colors as the same The visual system funds the most common frequency in the stimulus and subtracts it (ex. removes red hue from a sunset)

Unique yellow

Perceived when M and L receptors are stimulated and S is not, because S stimulates blue for blue-yellow channel...and since blue is not stimulated, blue-yellow channel is inhibited showing yellow The Red-green channel (both being stimulated by M and L wavelengths) cancel each other out and thus show nothing.... Therefore, only yellow shows

Unique blue

Perceived when S (short wavelength) receptor is stimulated and M and L are not (M and L transduce for green and red) So in this case... blue and yellow is stimulated showing blue, and red-green gets nothing (because M and L wavelengths not stimulated) and thus shows nothing

Transduction in Vision

Photopigments are stimulated by light energy and trigger action potentials Stimuli: For you to see an image, its light waves have to strike your eye Receptor steps: The light waves then enter the eyeball through the pupil, which determines how much light enters; the size of the pupil is controlled by the iris The cornea focuses the incoming light; then light rays are bent farther inward by the lens, which focuses the light to form an upside-down image on the retina Two types of photoreceptors on the retina, rods and cones, convert light waves into electrical impulses; those signals are processes by the bipolar, amacrine, and horizontal cells; information from those cells is passed to ganglion cells, which generate action potentials that are transmitted by the optic nerve Pathway to the brain: Information from the left visual field goes to the right portion of each retina, follows along the optic nerve to the optic chiasm, and then travels through the right thalamus to the right visual cortex Information from the right visual field goes to the left portion of each retina, follows along the optic nerve to the optic chiasm, and then travels through the left thalamus to the left visual cortex Resulting perception: As a result, you see visual details

Inhibition of return

Posner and Cohen (1984) Cue is made at the same spatial location as the eventual target Can't direct attention to the same spot in quick succession, so, after 300 ms, attention provides inhibition rather than facilitation to cue detection

Cortical Representation: X-topic organization

Primary sensory cortices represent sensory information in a very structured manner Similar parts of the sensory space are processed by adjacent portions of cortex

Unique Red

Red is perceived when L is stimulated...so red-green channel says red and blue yellow channel says yellow Does high frequency (>600nm) light look like pure red? No! Always looks yellowish red How do we perceive pure red then? Add blue! -- Blue cancels the red in the blue-yellow channel, leaving only the red channel Pure red is perceived when L wavelength light is mixed with S wavelength light

Rods

Respond to extremely low levels of illumination (greater sensitivity in low light) Responsible primarily for night vision Do not support color vision (achromatic) Resolve fine detail poorly Help see outlines of people (in gray) Concentrated at the retina's edges (retina periphery)

Bottom-up processing in attention

Salient (important/most noticeable) stimuli can attract attention (a car's brake light, loud noises, the tinking of a class, your name)

Perception

Selecting, organizing, and interpreting sensory information (interpretation--modern day digital camera)

Cognitive theory of neglect

Sensory input is being collected and processed Information is not attended, leading to mass filtering

Sensory Memory

Sensory systems can store input for a very brief amount of time Information is thought to be unstructured (not processed to a deep level: color and form but not meaning, etc) Vision: Iconic memory Hearing: Echoic memory

Visuospatial Sketchpad

Spatial and visual information is maintained in this memory store (working memory) There may be a rehearsal component (analogous to the need for the articulatory rehearsal)

Iconic memory

Sperling, 1960 Tachistoscopic presentation for a fraction of a second of four letter in a row (and there are three rows) Whole-report condition: Report as many letters as you can (subjects can only report about four letters) Partial-Report Condition: Immediately after the letters disappeared, a hi/med/lo tone was played, indicating which row subjects were to report (The top row is associated with a high tone, the middle row with a medium tone and the bottom row with a low tone) Results: Subjects were able to report the letters from any row Since the tone sounded after the letters disappeared, subjects must have had all the letters available to them for a brief time Evidence that a large amount of visual information is retained for a very short period of time

Auditory transduction

Stimuli: Variations in air pressure produce sound waves that arrive at the ear (outer ear) Receptor steps: These sound waves move through the outer ear and make the eardrum vibrate, and then... Move through the middle ear, causing the ossicles to vibrate - the ossicles' vibration causes the oval window to vibrate... Creating pressure waves in the inner ear's fluid; these waves end up at hair cells and cause neurons on the basilar membrane to fire neural signals (pressure waves cause the basilar membrane to deform--this movement mechanically triggers action potentials in specialized neurons) Pathway to the brain: These signals travel along the auditory nerve to the brain's primary auditory cortex Resulting perception: As a result, you hear sound

Evidence for the 2 systems of working memory

Subjects are much better at retaining visual/spatial information while retaining verbal information than retaining two different bits of verbal information or two different bits of visual/spatial information

Just Noticeable Difference (JND)

The smallest detectable change in intensity of a stimulus Ex.) If, when holding an object of 100 grams, it is necessary to hold an object of 110 grams to detect a difference in weight, the JND is 10 grams Ex.) Reading book while friend watches T.V. ⇒ commercial comes on and is louder than show → you look up, noticing something has changed → difference threshold is the minimum change in volume (the minimum quantitative change required for you to detect a difference) Increases as the stimulus becomes more intense Different sensory modalities (vision, pain, hearing, touch, smell, taste, kinesthesis) have different JNDs Ex.) If Weber's fraction as percentage is 33% for taste, that means that taste must be intensified by 33% in order to be perceived as being more intense, while light only needs to be increases by <2%

Absolute threshold

The smallest detectable level of a stimulus (minimum intensity of a stimulation that must occur before you experience sensation) Ex.) Vision -- a candle 30 miles away in complete darkness

Tonotopy

The spatial arrangement of where sounds of different frequency are processed in the brain Tones close to each other in terms of frequency are represented in topologically neighbouring regions in the brain Topographic organization (very similar to retinotopic organization for the visual system)

Coding

The way information is encoded in neural signals

Inhibition of return: objects

Tipper et al. (1991) Same paradigm as Posner and Cohen, but this time, the objects move Inhibition now occurs despite different spatial location of the cue on the object Evidence for object-based attention

Perception's Goal

To create high level description of the world Challenge: Raw sensory input contains none of this --Raw sensory input is just an array of color and luminance values...its perception's job to make sense of it and create 3-D objects for vision, and transform sequence of air pressure values to words for audition

Interactions of information

Top-down and bottom-up information can interact for attention Gunshots and Yelling--both will attract your attention on the street, but a gunshot won't attract your attention at the firing range and yelling won't attract your attention at a football game

Attenuation theory

Treisman (1964) Unattended information is attenuated, but not filtered out Leaves open possibility of processing unattended information Shows that from sensory input, two things can go to attention, one will go right to processing, but the other (unattended information) is still there for a certain amount of time and in that time, has the chance to be processed

Attention as bottleneck

We cannot possible process all the information coming in from our senses Attention acts as a filter, allowing us to four our processing resources Information that is attended is processed better than information that is not attended The processing advantage afforded by attention (or disadvantage caused by lack of attention) can be substantial

Light based depth cues

We make assumptions about the location and effects of the light source Do this by finding lighter areas (where light is coming from) and darker areas (no light coming from here...could be a shadow)

Templatic Hypothesis

We store images of encountered objects Recognition occurs when we match a stimulus to a template Ex.) Letter recognition -- See a stimulus for a letter...and find the letter template that it matches (so if the stimulus is "A," it will find a template "A" in a word, like SPA, and realize it is an "A") Problems: We can recognize new instances of objects that we've never seen before; We can recognize objects from angles we've never seen before (ex. the "A" is italicized or a different font than the original template for "A"...but we can still recognize that the letter is an "A") and we can also recognize objects even when features are missing