Psych 316 - Exam 2

Shortcomings of RBC

- Greebles experiment - Geon recognition alone is not enough to recognize all objects - We can still discriminate objects with the same geons (ex:bears) and objects w/in the same category (ex: your cat vs other cats) - texture and color actually does matter for recognition in certain cases such as same class distinction (ex: bears) - Some objects cannot be recognized based on geons (ex: water)

What and where pathways

- Pahtways interact with object motor and visual systems to work togeether - Lesions made in either the temporal and parietal lobes of monkeys - monkeys performed either an object discrimination or a landmark discrimination task - Monkeys with parietal lesion could not perform the landmark discrimination task - Monkeys with temporal lesion could not perform the object discrimination task.

Object discrimination (What)

- Pick the correct shape (triangle or rectangle) for a reward (go for the unfamiliarized object) - Monkeys with temporal lesions cannot perform this correctly

Landmark discrimination (Where)

- Pick the shape closer to the cylinder for a reward - monkeys with parietal lesions cannot perform this correctly

Assumptions of RBC Theory

1. Geons can be recognized from any angle (except accidental angles) aka viewpoint variance assumption 2. Geons are the alphabet of objects. Color and texture, along with context aren't important as long as you can see the geons

pattern recognition

1. decipher visual stimulus correctly 2. Memory of what the stimulus is 3. Bridging the gap between them - seems effortless, but has proven very challenging to recreate with artificial intelligence

recognition by components theory (RBC)

36 geons make up the visual object alphabet. Objects are made by combining geons at their edges. This model assumes a hierarchy of detectors - Information processing theory: 3 stage pattern recognition - Biederman

View Normalization

3rd stage of the hierarchical model of object recognition - Allows a viewpoint-invariant representation to be derived. - This is a controversial idea because evidence generally suggests that successful object recognition does not require viewpoint-invariant representations - We don't usually store a 3d prototype in our mind, but a prototype of it at common angles - We prob only do this step if we don't recognize an object at first glance

structural description

4th stage of the hierarchical model of object recognition - During this stage, individuals gain access to stored knowledge about the structure of objects - memory of what objects are supposed to look like

dependence on orientation

A distinctive characteristic of face recognition is ____________ __ __________. This is demonstrated by the face inversion effect

Thatcher Illusion

A phenomenon in which people have difficulty noticing local feature changes (e.g., upside down eyes or mouth) in an upside down face.

stimulus

According to Bruner, our perception of a stimulus differs from, and goes beyond the ___________ itself - We don't "really see what's out there" - involves expectations and prior knowledge

innate, geon assemblies

According to RBC theory, Recognizing geons is an __________ skill. What is learned is the name of geons and _________ __________

Where pathway

Also called the dorsal pathway - Object recognition is more than just what something is, but also where it is.

What pathway

Also called the ventral pathway - temporal lobe - involved in recognition and memory

visual/perceptual vs functional properties

Although some evidence supports the natural vs artifical contrast (see semantic system), another possibility is _________________ vs _______________ _____________ - natural objects defined by visual features - Artificial objects are defined by functions - neuroimaging experiments failed to provide clear support for natural vs artificial view - More fine-grained deficits have also been found. Some patients have shown major deficits in naming animals but not plants and vice versa

top down processing

Ambiguous figures provide a good example of what we mean by "beyond the information given". Although the stimulus remains the same, our perception can change drastically depending on how we interpret the stimulus using this type of processing

prosopagnosia

Are faces special? YES (even though pretty resounding no) viewpoint: - One piece of evidence comes from individuals with ________________. - These patients lose their ability to recognize faces, though they can recognize other objects

no

Are faces special? ____ - See experience-dependent plasticity - A prospagnosic farmer could not recognize his individual cows - dog show judges show the inversion effectt for dogs as they do for humans - Greeble novices the part of the fusiform not engaged, once they become experts the area becomes more active

multiple-views account

Arguing viewpoint against RBC - Suggests that we store a few prototypical views of an object in our mind and match what we see with those stored views (things typically have a standard view) - When an object appears at a viewpoint that does not match what you have stored in memory, your object recognition performance should suffer

viewpoint invariance assumption

As long as all geons can be clearly identified, object recognition performance should be the same regardless of viewing angle - associated with RBC theory

bottom-up processing

Context effects: information is ambiguous at the feature and letter levels Information is disambiguated at the word level - Objects are recognized by their parts and combined to create the whole using this type of processing

Top-down processing

Context effects: information is ambiguous at the feature and letter levels Information is disambiguated at the word level - When the interpretation is ambiguous, or when it is possible to parse the features in multiple ways, we use context to guide the parsing mechanism using this process

Contrast reversal

Contrast reversed faces are also much more difficult to recognized than contrast reversed objects - configural processing isn't involved here so there must be going on

Geons

Different three-dimensional shapes that combine to form three dimensional patterns - part of the RBC theory

Recognition test

Evidence for the face inversion effect: - Yin sowed Ss pictures of houses or faces during a study phase - During the _____________ ______ phase, Ss were shown upright or inverted houses and faces. - The studied pictures were mixed with new pictures and Ss asked to judge whether each picture was seen during the study phase - House could recongize about the same inverted w/ upright - faces had much harder time recognizing inverted faces but could recognize upright faces very well

experience-dependent plasticity

Faces are typically recognized at the individual level but other objects are not (within vs between-class discrimination) - We have more expertise with faces - If we develop expertise at identifying objects in a particular category, recognition of these objects activates the fusiform gyri, which are allegedly used only for face recognition

Edge grouping by collinearity

First step in the hierarchical model of object recognition - Rope example from text - stage of processing where edges of objects are derived (common line)

Wong and Weisstein (1982)

Flashed a vertical line that is slightly tilted to the left of to the right and Ss must discriminate its direction of tilt - Line flashed alone on a plain background or on the face-goblet picture - On face-goblet picture, Ss asked to percieve either the goblet or the face - 4 different conditions created - used a star in Ss blindspot, if they saw the star, their eyes were moving

whole, sum

Gestalt psychologists argued that our perception of the visual world is organized in ways that the stimulus input is not. The perceptual "_______" is often different from the _____ of its parts

figure-ground separation

Gestaltists claimed that the figure is perceived as having a distinct shape or form and the ground lacks form. This suggests that figure perception and ground perception may be governed by different processes. - where an object is and where it begins is the 1st step of recognition

visual perception

How we receive the most pecreptual input

fusiform gyri

If we develop expertise at identifying objects in a particular category, recognition of these objects activates the __________ ________, which are allegedly used only for face recognition - Greeble novices the part of the brain not engaged, once they become experts the area becomes more active

Evidence for feature binding

Integrative agnosia: patients w/ this condition have trouble combing or integrating features of an object - Patient HJA could not find an inverted T among upright Ts (although he could identify an inverted T when it is presented alone) because he found it hard to group the distractors together

featural vs configural processing

Martha Farah proposed two pattern-recognition systems - Called that the configural processing system is damaged in people with prosopagnosia

visual

Natural objects are defined by _________ features

interact, interactions

Object recognition often goes beyond visual recognition alone - we _________ with objects - Physical _____________ with objects often facilitates object recognition - What and where an object is supports our perception and action within our world

Evidence for structural description

Object-decision task: Ss see pictures or drawings of real and pseudo-objects, and they must decide which are real. - Some patients perform poorly on this task even though they perform normally on tasks designed to assess earlier stages of object recognition - Some patients perform extremely poorly when they have to name objects presented visually, but can perform normally when naming objects presented verbally

generalize

One remarkable feature of our ability to recognize patterns is that vastly different stimuli can be recognized as the same object. - able to _____________ to recognize

configural, upright

Our perception of faces are specifically built to detect _________ relations from an _________ position - when a face is inverted, that ability is lost - Our perception of faces upside down and right side up is very different!

Evidence for Edge Grouping

Patient DF had severely impaired object recognition ability. She recognized only a few real objects and could not recognize any objects in line drawings - She also ad trouble recognizing line orientation which is important for detecting edges - Action & line recognition is processed in different places in the brain: was able to rotate a card into a slot but couldn't rotate it to match a line at various angles

Evidence for semantic system

Patients with an impaired semantic system can show category-specific deficit - impaired for natural objects but intact for artificial objects( more common as living things tend to look more similar visually) - impaired for artifical objects (though much less common) - Double dissociation shown

bottom, top

Pattern recognition is a stage between low-level sensory input and high-level cognition, and it is affected by both _______-up and ___-down processing -Pattern recognition doesn't require you to recognize every part of something to know what the whole of it is. - Lower level processes can be affect by top-down aswell

Support for RBC theory

People are much better at identifying objects when geons can be identified. - Junction of lines going together helps interpret the geons

detail, insensitivity

Perception of figure and ground has been suggested to involve two systems with different information processing characteristics. Figure perception is characterized by _________ analysis and high resolution, while ground perception is characterized by low resolution and __________ to phase information. - Nothing to do with where the line is shown on screen, everything to do with the background - top-down processes

associative agnosia

Perceptual processes remain intact but object recognition is impaired because of difficulties in accessing relevant knowledge about objects from memory. - Can take what they see, but can't connect it with their memory

configural processing

Recognition of larger configurations. Responsible for analyzing the spatial relations among features in a face. - One out of two of Farah's proposed pattern-recognition systems - Farah claimed this system is damaged in people with prosopagnosia

featural processing

Recognition of simple parts and the assembly of those parts into larger wholes - One out of two of Farah's proposed pattern-recognition systems

hierarchical model of object recognition

Riddoch and Humpreys proposed a model to account for the various deficits in object recognition shown by brain damaged patients - 1st 3 steps are perception based processes - damage to later stages you should be able to recognize basic things. Earlier stages barely able to recognize. - Information processing model with 5 steps: 1. edge grouping by collinearity 2. Feature binding into shapes 3. View normalization (sometimes bypassed) 4. Structural description system 5. semantic system

Greebles experiment

Testing viewpoint independence. - Ss learned Greebles (objects never seen before) over 2 week period - Ss decide whether 2 Greebles, presented in succession, are the same. Shown either at the same angle, or rotated up to 75 degrees - Results: more rotation generally means slower response time

hierarchy of detectors

The RBC theory assumes this - The first level detects curves, lines, corners, edges, etc. - These feed into the next level that detects geons - Feeds into the next level that detects geon assemblies, which allows specification of relations among geons

Semantic system

The final stage of the hierarchical model of object recognition - At this stage, people gain access to stored knowledge of semantic (nonvisual) information relevant to the object - Unable to match memory of an object to what is being seen visually

visual agnosia

The impairment of visual object recognition in people who possess sufficiently preserved visual fields, acuity, and other elementary forms of visual ability to enable object recognition , and in whom the object recognition impairment cannot be attributed to... loss of knowledge about objects.... Thee impairment is one of visual recognition rather than naming, and is therefore manifest on naming and non-verbal tasks alike

environment, 3d

Visual perception takes into account the __________ and _____ knowledge to understand stimuli using top-down processing - Ex: Brightness illusion, things under a shadow should be darkened

Evidence for view normalization

Warrington and Taylor asked patients to recognize objects presented at either a normal or an unusual view. - These patients performed particularly poorly when objects were shown at an unusual angle/ - The same occurred when they showed two pictures simultaneously, with each depicting an object at a different angle, and had patients judge whether they were the same object

sitting in the chair

We typically consider object recognition as involving perceptual and memory processes - you see an item and then identify it, this is called the "___________ ___ ____ ________ " approach - object recognition often goes beyond visual recognition alone

temporal, ventral

What pathway - Object discrimination - Monkeys with ______ lesions cannot perform this correctly - __________ pathway

parietal, dorsal

Where pathway - landmark discrimination - monkeys with ______ lesions cannot perform this correctly - ___________ pathway

embedded figures

________ ______ are percieved if the overall form is parsed in a particular way. If we know what we are looking for we can impose that order on the stimulus - Cognitive control is effecting processing - top-down processing

functions

artificial objects are defined by __________

feature theory

complex patterns are identified by first recognizing the simpler components or elements of the pattern, and then combining the elements into the complex structure - bottom-up processing - distinctive features matter: features that distinguish one stimulus from another should be particularly important

fusiform

fMRI evidence suggests that the __________ face area specializes in face recognition - usually use the right side of the brain.

Feature binding

hierarchical model of object recognition stage 2. - Object features that have been extracted during the edge grouping stage and the feature detection stage are combined to form shapes - This stage is akin to recognizing geons/ geon assemblies in the RBC

Prosopagnosia

inability to recognize faces

face inversion effect

much more difficult to identify faces upside down compared to non-face objects - This a demonstration of dependence on orientation in regards to face recognition

apperceptive agnosia

object recognition is impaired because of deficits in perceptual processing - Can usually recognize small pieces of an object but the overall becomes difficult - Patients will say items look very indescript

integrative agnosia

patients with this condition have trouble combining or integrating features of an object

aphasia

unable to comprehend/produce language

amusia

unable to recognize groups of sound as music

object agnosia

unable to recognize objects

tactile agnosia

unable to recognize objects through touch