Cognitive Psychology (Chapter 3)

Physiological cues

-Accommodation -Convergence

Mirror neurons

-Located in premotor cortex Neurons that respond both when a monkey observes else (usually the experimenter) grasping an object, such as food on a tray and when the monkey itself grabs the food. One function might be to help understand another person's actions and react appropriately to them.

Experience-dependent plasticity

-the brain is changed or "shaped" by its exposure to the environment so it can perceive the environment more efficiently. (ex. Of cat)

Speech segmentation

Because of one's knowledge of language, one is able to tell when one word ends and the next one begins - Each listeners experience with language (or lack of it) is influencing his or her perception. - Knowledge influences perception (perception depends on knowledge).

Template Theory

In a way of looking at it from a pictorial perspective- I show you a shape for the first time, when you see this, you make a mold/template of this shape. Every object that I look at and can remember is recognized because I've made a template for it. If I see an A, I recognize it because I have a template in my brain. Recognition comes by matching the stimulus to a template imprint already in the brain. This is some kind of coding process- there are unique brain symbols corresponding to the letter A. If there is a template that you don't recognize, then you don't know what the object is. You recognize it if it matches a template. It's like scanning a barcode. Each object has a different barcode, even if it's the same object of different sizes. • Strength- have unique code for every stimulus • Search for template in brain, but its not there, so don't recognize the shape • You recognize something if it has a template, but if it doesn't then you don't • Weakness- Need a separate template for each and every object, but also for every version of every object- every size, shape, color. Ex- different variations of a triangle. • Template is like a barcode in supermarket. Each barcode is associated with a different stimulus, and cheerios 32 oz. needs different barcode than cheerios 16oz. • Lets say you have a template for a small triangle, when you see a large triangle, you wont know that it is a triangle unless you make a template for it.

Binding

Issue in bottom up theory - when we look at brain functions we note that different feature detectors are different parts of the brain- one part for lines and edges and one part associated primarily with color information, and these are separate from each other. If I have one part of brain picking up edges and lines and another part picking up on color, and another part picking up on motion- stationary or moving, how do I put these all together?! I don't see these as independent things. They seem to be all bound together into one coherent unit. In this bottom up theory, how do the diff categories of features of brain get connected into one single coherent recognizable object?

Law of Visual Angle

Lens perceives the object, inverts it, and projects it on the retina. Size/Distance in lens= size/distance in retina. Note that retinal image is far smaller than lens image. So as Size as seen by lens gets bigger, then we perceive that this person is bigger. The bigger the person, the bigger the RIS (retinal image size). As distance becomes bigger, then the image looks smaller. Thus size and distance effect retinal image size. Perceived Distance= Retinal Image Size X Distance • s=RIS= Retinal Image Size • Relationship between image and size of image on retina. • If increase size of object (S), RIS also increases • If I double object, that will double RIS. If I half the object, the RIS will be halfed.. • S/D = s/d.

Stabilized images

Microsaccadic: helps refresh neural cells. It helps neurons from being fatigued. Microsaccades shift image back and forth between neurons- but if you eliminate them, you have stabilized image that stays on the retina, letter starts to break apart and disappears. There is no refreshment of microsaccades; neurons cannot maintain continuous activity and therefore loose the image feature by feature. So if looking at an F without microsaccades, lose fire the vertical line, then horizontal line. The dissolution of each feature means that you will slowly but surely stop visualizing the letter.

Associative agnosia

No difficulty in drawing an object, but don't know what the object is. Can't associate the specific object with what they are looking at. Put when they touch it, they know what it is. Can't connect visual stimulus with that knowledge.

Helmholtz's theory of unconscious inference

Some of our perceptions are the result of unconscious assumptions that we make about the environment

Word Superiority Effect

Subject needs to distinguish between two letters- D or K. looking at screen and there will be a slot, and one of the letters will show up in slot. From feature analysis perspective, this isn't hard, obviously a K doesn't have rounded parts, and the D does, so it is distinguishable. Weird thing is- if subject given same task, but put in context of a word (WOR_), they are faster. As long as word is pronounceable it will be recognized faster than just the letter alone being shown. Feature by themselves- more primitive level. As soon as I bring in top down information, context, that information can be very helpful in analyzing, reframing and identifying information.

Confusability

Things that share features are more likely to get confused under noisy conditions- visual and auditory. Example- in a noisy condition, may confuse R and P, and F and E- template perspective makes no sense, but from feature perspective, they share so many features, so easy to confuse. More features that are shared, more likely to be confused.

Dissociations

situations in which one function is absent while another function is present (single- studied in one person. Double- require two or more people).

Non- veridical perception

this is an illusion. We see things differently than the way that they actually are. If you move something further away, it looks smaller, so it is an illusion.

shading and shadow

when you add a shadow, it gives a depth and sense to a shape. Adding shadowing and shading makes me see cubes

Top Down Processing

• Effect of Experience, context, expectation • Operate at high levels and feed downwards and effects how we interpret the features. When you have "12, 13, 14" you recognize the middle as the number 13. And yet you can take the same features of the 13 and make it "A, B, C" (where the B is created from the same 1 and 3 shape). The features of the 1 and 3 haven't changed; you just see them differently depending on the context. Same stimulus looks like two different things. Top down analysis- here I'm looking at numbers, so it's a 13, or here I'm looking at letters, so it's a B. "Aoccdring to a rscheearch..." letters are completely switched around- with top down we can read this, not with bottom up. Meaning allows us to reframe these words into meaningful words. When create a context- can fill things in- ex: blotted letters once you have context, you can figure things out. But we cant just have context, context can only get its meaning from analysis of stimuli. - Word Superiority Effect - Physiological point of view- perception of an object is based on: 1. Signals representing the object 2. Signals representing other aspects of the environment 3. Feedback signals representing prior knowledge or expectations - Perception depends on information provided by stimulation of receptors plus additional information such as information about the environment and a person's prior knowledge.

Convergence

• if you look at something close, you converge your eyes. If it is further away, you diverge your eyes. • related to the distance of object • Only work to about 20 or 30 feet, bc after that your eyes become parallel to each other

Bottom up Theories of Form Perception

"image demons." This layer just processes the image based on the picture on your retina. "feature analysis"- this layer takes the object and breaks it down into individual components. There are different processors- demons- and each one has a specific job. Each one's job is to look at the image and find its feature. Demon 1 responds to only a vertical line, Demon 2 responds to a horizontal line, Demon 3 to a tilted line, etc. "cognitive demons" that put objects together. One of these Demons responds to the combination that forms "F;" another responds to the combination that forms "A," etc. Each of the object demons looks to get each of its features activated. Each object demon looks downstream for a combination of features "decision demon"- makes the decision about how to see the object, despite the tremendous amount of activity. Whoever makes the most racket, i.e. whichever object demon has the most activity (because it has the most features activated) will be recognized. Conscious perception Bottom up theory- I take the raw image, break it into its features and then build it back up to recognize it. With this model, the more similar objects are to each other, the more likely they are to be confused. • Benefit: if I have two A's that are different sizes, with this theory they are the same to me, because they have the same features that are activated by the stimuli, even though they are different sizes. Even if a line is tilted, it will still activate the features

Perceiving odor intensity

- Even though stronger sniffling causes more odor molecules to stimulate the receptors, this did not influence the participants' odor intensity ratings. - Just as the perceptual system takes distance and perhaps other factors into account when a person is perceiving size, the perceptual system takes sniff intensity into account when a person is perceiving odor intensity. - While perception may start at the receptors, I depends on additional sources of information as well. - The goal of the perceptual system is to provide accurate information about what is out there in the environment.

Algorithm

A procedure that is guaranteed to solve a problem - Gestalt rules are heuristic because they are best-guess rules based on how the environment is organized, that work most of the time, but not necessarily all of the time. - A heuristic is faster

Recognition by Components (RBC) by Biederman

Basic shape units form a geometric perspective that can all be derived from cylinders, there are 36 of them: Geons (geometric ions, basic units). When we stick them together we come up with objects. All we need to do is recognize 3 geons in an object and will be able to identify it as an object. Another kind of building block, higher level than a feature. Attractive bc takes us into the real world, not just numbers and letters. Each individual geon is unique. Doesn't matter how you change the orientation of the geons. It accomplishes- more powerful bottom up theory (not simply looking at something flat but rather 3d), accomplishes this kind of shape constancy. Can recognize chair by putting together different geons- geons don't change as I rotate chair in different views. It is viewer independent. As long as geon is recognizable and I have three geons that are recognizable, I have an object that is recognizable, even if chair is blocked out by table. Question- are geons built up of feature detectors? Very little physiological evidence that part of brain has certain geons. But there is behavioral data- argument about visibility and recognizeability of something- wine glass and watering can- even though don't have all the lines, I have the critical juncture points so can recognize the object. As long as you have enough of geons and junctures of geons, you can recognize the object.

Retinal image size (RIS)

Brain is trying to derive the size of the object out there from what my sensory systems are telling me. If my RIS=2 that is what comes into the brain. Brain has a little box that measures RIS. • RIS depends on size of object but also the distance of the object • D is inversely proportional to RIS. RIS gets smaller with distance. If I double distance of object RIS will be half as large. The only sensory information brain has is RIS, but that is ambiguous bc when comparing two objects to each other, psychological dilemma- I don't know why I'm getting larger RIS, is object larger or closer? Brain needs to figure out size of object. Projection of closer person is larger than the person further away, and that is all that is projected to the brain. Brain doesn't know why though. This is the dilemma- projection law creates a proportional change in size, inverse proportional change in distance, so don't know what to attribute difference in size to. Perceived size= Retinal image size X Distance

Propsopagnosia

Cannot recognize faces, has a specific deficit with faces. • High level analysis for shape and face recognition- inferior temporal cortex of temporal lobe, fusiform face area- specifically associated with inability to recognize faces- fMRI studies evidence. Area of brain associated to face recognition, would say that this is different than object recognition. Study- looked at face perception as separate element from object perception. Ex- fruit, turned upside down is a face- someone with propsoagnosia won't see face but will see fruit, the other agnosias will only see face, and not fruit.

Formed perception

Constancy process where you make evaluations, example- rectangular eraser, only see it if you look at it if in center, but if you're towards the right or left it won't look rectangular. 1. shape 2. color (chromatic, achromatic)

Illusion of retinal image size

Cow- perspective cues mislead. Same distance (bc it is on a picture) from you and same RIS, but one looks to be further away and looks larger- illusion. The perspective cues tell you that it is further away. In the real world, when something gets further away, the RIS gets smaller. But in a picture, this doesn't happen, and that's why I have an illusion.

Cues

Cues can be monocular (only need one eye) and binocular (need both eyes) cues • pictorial cues=monocular, can look at pictures with one eye • physiological cues: - accommodation= monocular - convergence= binocular What kind of distance do these cues give me? • Absolute information or relative information about distance • Absolute- Tells me what distance is, precise (ex- 20 feet) • Relative- not precise: that's closer, and this is further away • Pictorial- relative, closer and further away • Physiological- absolute, need to accommodate and converge precisely for the different distances. If you are trying to figure out RIS x D= S, you need absolute information because it is an equation. Want to know actual distance of the object that we get from accommodation and convergence (physiological cues).

Apperceptive agnosia

Difficulty at perceptual basic level of analysis- hard to see anything other than individual features. They can draw A with eye closed but if asked to copy an A, can't process it. If they touch object, they have no difficulty in identifying it. Specific to visual processing. Different orientations are also difficult. -occipital lobe

Distal vs. Proximal Stimulus

Distal- stimulus out there, example- a voice Proximal- on sensory organ, retinal stimulus on eyeball

Parallel processing

Doing two things at the same time. o when feature detector is active, it sends out signal, process by feature detector sending signals to all the places looking for a vertical line. Vertical line detector, sends signal to all letters looking for vertical line. Each unit is dedicated to whoever wants the information, but just one person.

Aggregation

How do I put things together and make them into a unit? Random dots- nothing aggregates them together • Grouping by proximity- segregated dots and put them together in groups so some are closer to each other. • Grouping by similarity- such as color, creates sense of organization

Principle of Componential Recovery

If we can recover (see) an object's geons, we can identify the object.

Emmert's law

If you have two objects same RIS, and one appears further away than the other, the object that appears further away will appear larger because of pictorial cues.

Object discrimination problem Landmark discrimination

Monkey experiment - p.72 What pathway-pathway leading from the striate cortex to the temporal lobe Where pathway- pathway leading from the striate cortex to the parietal lobe (the what pathway- involved in initial perception of the cup and the where pathway- in determining its location).

Accomodation

Need to change thickness of lens as object comes closer to me or further away. • relationship between distance and accommodation is precise. • Brain's job is to control accommodation so objects are clear on retina. Brain can figure out distance based on accommodation. Accommodation is uniquely linked to each distance that provides information to object size of what distance is. • If you know what the accommodation is you are able to figure out the distance. If you know the change in accommodation, you know the change in the distance. • Only works to about 20-30 feet, that's why some people need to wear glasses.

Figure ground

Need to distinguish between what figure is and what background is. The object is the center surrounded by the ground. Ex- vase and face illusion.

size constancy

Our brains seek to make the world as consistent as possible. The person in front of the room looks bigger, but the distance compensates. perceive objects as being the same size regardless of their distance. Even though my retinal image size shrinks as a person walks further away from me, I understand that the person themselves are not shriveling; the person stays constant. Though if misperceive the distance, then misperceive the size. This is called an illusion - your perception is different than the reality in a non-veridical view. You do not require knowledge, cognitive awareness to solve problem of size constancy

Oblique effect

People can perceive horizontals and verticals more easily than other orientations

Gangfel

Person put in a giant bubble, and light is shown on the bubble, bubble creates homogeneous light (bright green) that covers the whole field, and look at it for a few seconds, and the entire thing then disappears. If there's a black dot, the color then reappears- once my brain has something to distinguish it becomes reinvigorated, active. After a time, the surface and color disappear because there is no distinction. If it doesn't change, our brains cannot register it.

Hubel and Wiesel

Recorded from occipital lobe (responsible for vision), took electrodes and stuck it in occipital cortex of monkeys into a single cell, measured that cell and they show monkey pictures and things- if shown in a particular location, neuron fires and gets excited- implying that the neuron sees the stimulus. Neuron fired to vertical line. If line is a little titled, it stops responding, and a different neuron responds. That neuron has a job- a feature demon/detector- responsible for seeing vertical line. Column of feature detectors looking at orientation of stimulus. Higher levels of brain, those feature detectors only respond if you're looking at combinations of features. Highest level in temporal cortex- neurons that respond to whole objects. This is neurophysiological evidence that in the brain there are several neural feature detectors.

Heuristics

Rules of thumb that provide a best-guess solution to a problem (may not result in a correct solution every time).

feedback signals

Signals that travel down from higher centers to influence incoming signals

Perceptual organization-

The way elements are grouped together to create larger objects 1. Laws of perceptual organization- elements in the environment are organized, or grouped together 2. Law of good continuation- points that, when connected, result in straight or smoothly curving lines are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path. Also, objects that are overlapped by other objects are perceived as continuing behind the overlapping object. - What we perceive is based is based on what usually happens in the environment 3. Law of pragnanz (law of good figure, law of simplicity)- every stimulus pattern is seen in such a way that the resulting structure is as simple as possible (ex. the five circles) 4. Law of similarity- similar things appear to be grouped together 5. Law of familiarity- things that form patterns that are familiar or meaningful are likely to be grouped together (ex. Dalmatian picture).

Helmholtz

Unconscious interference: my brain is inferring something of size of object based on RIS and D, it is unconscious, doesn't have to do with awareness of calculation.

Law of Pragnanz/ principle of simplicity

We organize information in terms of the simplest form. -simpler to see this as a line and curvy line than breaking it into pieces.

Likelihood principle

We perceive the object that is most likely to have caused the pattern of stimuli we have received experiences we have had with similar situations in the past-. (rectangle example). - Process of perception is similar to the process involved in solving a problem (can be by applying his or her knowledge of the environment in order to infer what the object might be or the process is unconscious- unconscious inference

Principle of closure

We tend to see objects without paying attention to the spaces. if there is a circle drawn with a little gap at the top, you see it as a circle. If there is a circle structure made out of dotted lines, you see a circle. You don't see groups of line. You use the principle of closure to make the continuity, forming a circle. A component of this is due to experience and familiarity. -we spontaneously organize and put things together into segregated components -illusory contours: square we tend to fill in

Shape

When you look at an eraser straight on, it looks like a rectangle. If you look at it from the side, it looks like a trapezoid. The shapes of the tables in the Shepard's turning table illusion are the same. One appears to be longer and the other shorter, but really it's the same shape

Good continuation

When you look at an object see it as most simple pathway. - let's say you have a straight line and then a curvy up-down-up-down line on top. Most people see a straight line and wavy line going through. There are so many ways to perceive this drawing- you could see arches and upside down arches. You could see the drawing in different pieces. But no, most people see a straight continuous line and a wavy continuous line. We see continuity. The principle again is simplicity- this the simplest way to see the drawing.

Color

chromatic= real colors achromatic- different shades of gray Achromatic- white reflects color back, white surface can be in a shadow, so light hitting it is really diminished. How your mind reevaluates things in shadow, A and B are same colors but don't look like it. The illusion is how your brain evaluates the shades between light and dark surfaces. Square A and B look like they are different shades of gray. If you take a gray swatch and move it over the two boxes, they are the same color. If you take out all the shadowing, you see that they are the same color when out of context. The brain changes the reality of what you see when it is taken out of context. Relationships change the way you perceive tings. Our brain takes the information given from the environment. When context is in, brain does all these evaluations and reevaluates everything. Brain takes info and recreates the environment. To be able to distinguish a distance is what thought is all about We don't perceive information correctly, except in areas of change. The ability to distinguish differences is what our brain pays attention to. We look for change, comparisons, and difference. When things are the same, we don't pay attention. The most basic human thought is the ability to distinguish a difference.

Pictorial cues

cues of perception and depth - texture gradient -linear perspective -shading and shadow -interposition

segregation

distinguishing one object/thing from another -developed laws of segregation- first set of cognitive processes we have to engage in before getting into process of object recognition

Serial Processing

doing things in an order. - with Selfridge pandemonium- break object into features, then put features together for letters, put letters together to get words.

Light- from- above heuristic-

light is coming from above One reason we are able to perceive and recognize objects and scenes is because of our knowledge of physical characteristics of our environment. We also have knowledge about regularities of the environment that indicate what types of objects typically occur in specific types of scenes.

Common fate

operates through a dynamic/movement, when something moves together, it organizes together as a unit. Example- someone walking we see as a unit because of the principle of common fate- they are all operating and moving together.When you move, your arm, head, and mouth are all moving, so we associate it as a unit because it's moving together.

linear perspective

parallel lines converge in a distance

Action Pathway

pathway from the visual cortex to the parietal lobe (corresponds to the where pathway).

Physical regularities

regularly occurring physical properties of the environment (ex.- there are more vertical and horizontal orientations in the environment that oblique (angled) orientations.

Audiovisual Mirror neurons

respond when a monkey performs a hand actions and when it hears the sound associated with this action

texture gradient

sense of depth, artist uses depth cues to give a sense of depth. In general, things closer to you have a coarser and detailed appearance. When the object is further away, the gradient is finer

Field independent processing

someone who can see in a mushed organization as being independent, see shapes independently as a separate shape.

Semantic regularities

the characteristics associated with the functions carried out in different types of scenes.

Perception Pathway

the pathway from the visual cortex to the temporal lobe (corresponds to the what pathway)

Brain ablation

the study of the effects of removing parts of the brain in animals. the goal is to determine the function of a particular area of the brain

interposition

when you overlap shapes, it looks as if one is further behind and one is closer up.

Veridical perception

you see correctly the way that things are

Issues of geons

• Easy to identify an object based upon its geon, but what is missing is distinguishing between 2 geons- if you have two objects made up of same geons, you will think they are identical • Object recognition is mainly viewer independent. Example- we can imagine another possibility that analyzes object recognition is shape analysis, you have a chair and you've seen it from all different vantage points- arguments been made that maybe its viewer dependent analysis where we store individual variance of objects, template theory- I have a template for a letter and in every orientation. I may have a few of the important identifying views of an object. When you see a noncanonical view- atypical view, chair from top down- very difficult to identify those objects. RBC theory helps us solve problem of independent viewer, shape constant.

The human "perceiving machine"

• One of the basic operating principles of the human brain is that it contains some neurons that respond best to things that occur regularly in the environment. Theory of natural selection- genetically based characteristics that enhance an animal's ability to survive, and therefore reproduce, will be passed on to future generations. According to the evolutionary process, the visual system may have been shaped to contain neurons that respond to things that are found frequently in the environment.

Shepard's Terror Subterra

• What if you don't have physiological cues but only pictorial cues?! two monsters that look different sizes, but really they are different sizes based on what pictorial cues tell me. There are converging lines and a texture gradient. The RIS for both men is 6. The distance information that the pictorial cues give tells us that one is further than the other. One looks like there is a distance of 10 and one looks like there is a distance of 4. Therefore, one size looks like 60 and the other size looks like 24.This is not true though, but we are tricked by the pictorial cues. Illusion arises from the fact that we use normal processes of size perception but in this case, can't use physiological cues, so we are limited to pictorial cues. This concept is called Emmert's law.