Perception of Scenes: Attention, Theories, Techniques, and Disorders, Slides of Brain and Cognitive Science

Download Perception of Scenes: Attention, Theories, Techniques, and Disorders and more Slides Brain and Cognitive Science in PDF only on Docsity! 1 10/14/2008 1 Attention: How do we perceive whole scenes? • Theories of attention • Techniques for studying scene perception • Physiological basis of attention • Attention and single cells • Disorders of attention • Scene recognition 10/14/2008 2 Typical Selection-in-Space Study (Posner) • IV1: Cue (stimulus that might indicate where (or what) a subsequent stimulus will be--valid vs. invalid vs. neutral) • IV2: Stimulus onset synchrony (the time between the onset of one stimulus and the onset of another) • DV: Reaction time (measure of the time from the onset of a stimulus to a response) Docsity.com 2 10/14/2008 3 Cueing as a tool for examining attention • Simple probe detection experiment 10/14/2008 4 Cueing as a tool for examining attention (cont’d) Docsity.com 5 10/14/2008 9 Many Searches Are Inefficient (serial or limited parallel) • Serial self-terminating search: items are examined one after another until target is found or until all items are checked • Limited capacity parallel process: “watering garden with adjustable spray nozzle” idea 10/14/2008 10 Conjunction Search • No single feature defines the target • Defined by co-occurrence of two or more features • Real-world conjunction search: where is the red station wagon in the following photo? Docsity.com 6 10/14/2008 11 Conjunction Search (cont’d) 10/14/2008 12 Modeling Visual Search • Feature Integration Theory (Treisman and Gelade): 1.Preattentive Stage 2.Attentive Stage Docsity.com 7 10/14/2008 13 The Binding Problem • A conjunction search with a binding problem 10/14/2008 14 Attention in Time • Rapid Serial Visual Presentation (RSVP) • Attentional blink Docsity.com 10 10/14/2008 19 10/14/2008 20 Attention and Single Cells • Three ways responses of a cell could be changed by attention 1. Response enhancement 2. Sharper tuning 3. Altered tuning Docsity.com 11 10/14/2008 21 Attention and Single Cells (cont’d) 10/14/2008 22 Docsity.com 12 10/14/2008 23 Disorders of Visual Attention • Most common: Visual field defect (usually due to damange to visual nervous system) • Less common: Neglect (inability to attend to or respond to stimuli in the contralesional visual field, typically after right parietal damage) 10/14/2008 24 Docsity.com 15 10/14/2008 29 Balint Syndrome • Reduced spatial localization abilities • Reduced movement of eyes • Inability to perceive more than one object at a time (simultagnosia) 10/14/2008 30 Picture Memory and Change Blindness Docsity.com 16 10/14/2008 31 10/14/2008 32 What do you actually see? Dan Simon experiment: In the midst… Docsity.com