8014645
Description
Flashcards by Allison Sonia, updated more than 1 year ago
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Created by Allison Sonia
over 7 years ago
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| Question | Answer |
| Principles of object recognition | Precision Unity- Although different pathways code for color and motion, we perceive them coherently Flexibly Robust- Our recognition of an image is surprisingly stable despite shifts in orientation, time of day, and occlusion by other objects Memory bound- Once we perceive and image, memories are triggered |
| Two pathways for visual perception | The "what" ventral pathway- inferior longitudinal fasciculus The "where" dorsal pathway- superior longitudinal fasciculus |
| Evidence for differences between the visual pathways | -Lesion studies with monkeys show difficulty discrimination shapes with temporal lobe lesions and difficulty discriminating location with parietal lobe lesions |
| The same basic components can form different items depending on their arrangement | |
| Component analysis of object recognition | (a) Stimuli for the three conditions and the mental operations required in each condition. Novel objects are hypothesized to engage processes involved in perception even when verbal labels do not exist. (b) Activation was greater for the familiar and novel objects compared to the scrambled images along the ventral surface of the occipitotemporal cortex. |
| The Study and Test displays each contain three objects in three positions. On object retrieval trials, the participant judges if the three objects were the same or different. On position retrieval trials, the participant judges if the three objects are in the same or different locations. In the examples depicted, the correct response would be “same” for the object task trial and “different” for the position task trial. (b) Views of the right hemisphere showing cortical regions that showed differential pattern of activation in the position and object retrieval tasks. | |
| The anatomy of object recognition | The parahippocampal area and posterior parietal cortex process information about places and scenes. Multiple regions are involved in face recognition including fusiform gyrus and superior temporal sulcus while other body parts are recognized using area within the lateral occipital and posterior inferior temporal cortex. |
| The role of motor system in object recognition | Our visual knowledge of many inanimate objects is supplemented by kinesthetic codes developed through our interactions with them |
| Two hypotheses about the organization of semantic knowledge (Category-based and property-based) | |
| Representational differences between the visual pathways | Physiological responses of neurons in each lobe are distinct Temporal lobe neurons are best suited for determining the identity of an object Parietal lobe cells are best suited for detecting presence and location |
| How is agnosia different from memory loss? | With memory loss a person cannot recall what an object is no matter what they do with it (tough it, taste it, etc.). A person with agnosia cannot recognize in object by vision alone but can identify it with other senses. |
| Identification vs. action in agnosia | The agnosia patient cannot match the orientation of the card to the slot but when asked to insert the card into the slot (motor activity) they can do it without problem |
| Ventral-stream lesions in patient with agnosia | |
| The hierarchical coding hypothesis | Elementary features are combined to create objects that can be recognized by gnostic units. At the lowest level of the hierarchy are edge detectors. |
| The ensemble coding hypothesis | Objects are defined by the simultaneous activation of a set of defining properties. This is in contrast to the "grandmother cell" idea. This theory says that stimulus recognition is based on the collective activation of many neurons |
| Grandmother cells | The idea that there may be a single cell that fires when viewing a certain familiar face |
| Perceiving objects | The founders of Gestalt psychology postulated a series of laws to explain how our brains groups the perceived features of a visual scene into organized wholes. Figure and ground- an object is a figure that is distinct from the background |
| Object consistency | Sensory input from the same object can vary when the object is viewed at different angles, in shadow, or another object is covering it. Despite this sensory variability, we rapidly recognize the objects and can judge if they depict the same object or different objects |
| View-dependent object recognition | View-dependent theories of object recognition posit that recognition processes depend on the vantage point. Recognizing that all four of these drawings depict a bicycle—one from a side view, one from an aerial view, and two viewed at an angle—requires matching the distinct sensory inputs to view-dependent representations. |
| Asymmetry between left and right fusiform activation to repetition effects | a. Consistent with view-invariant representation b. Consistent with view-dependent representation |
| The unusual-views test: Used to identify apperceptive agnosia | Participants are asked whether two images seen from different viewpoints show the same object or not |
| The shadows test: Used to identify apperceptive agnosia | Participants must identify the object when seen under normal or shadowed illumination |
| Integrative agnosia | Patients are unable to integrate features into parts or parts into coherent wholes |
| Associative agnosia | Patient can perceive object but cannot understand or assign meaning to them |
| Apperceptive agnosia | Patient has problems identifying objects based on limited stimulus information (most common with right-hemisphere lesion) |
| Superior temporal sulcus regions that respond to faces | |
| Face specific N170 | |
| Face specific N200 | |
| Face perception vs. just eyes | FG responds to full faces while the T6 responds to just eyes |
| Category-specificity of face processing | Fusiform face area- Faces Visual word form area- Letterstrings Parahippocampal place area- Places Extrastriate body area- Body parts |
| Locations of face and body recognition areas | EBA=Extrastriate body area OFA=Occipital face area FFA=Fusiform face area FBA=Fusiform body area |
| Prosopagnosia | -The ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intact -Individuals use "piecemeal" or "feature by feature recognition strategies |
| Prosopagnosia and focal lesions | |
| Autism and face perception | Autistic individuals show a reduction in areas that are most activated by face stimuli |
| Analytic versus holistic processing | Analytic: Emphasis on component parts, critical to reading, damage results in alexia Holistic: Emphasis on the overall shape of an object, critical to face processing, damage results in prosopagnosia |
| Facial features are poorly recognized in isolation | |
| Bottom-up processing | The perception of objects is due to analysis of environmental stimulus input by sensory receptors; this analysis then influences the more complex, conceptual processing of that information in the brain |
| Top-down processing | The perception of objects is due to the complex analysis of prior experiences and expectations within the brain; this analysis influences how sensory receptors process stimulus input from the environment |
| Change blindness | -Fail to detect a change in an object or a scene -When detecting the difference between two scenes we identify important changes more quickly, more likely to notice improbable change, do not store detailed representation of the scene. |
| Inattentional blindness | -Fail to notice when an unexpected but completely visible object suddenly appears -Simons and Chabris' basketball study |
| Similarities between change blindness and inattentional blindness | -Both involve top-down processing -When an object appears that is not consistent with their concepts, expectations, and memory, people often fail to recognize this changed (change blindness) or new (inattentional blindness) object |
| How does perception act? | Perception is not like a video camera in our head recording experiences. Perception is an active and constructive process |
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