1 / 42

Attention & Scene Analysis 2

Attention & Scene Analysis 2. PSY 295 – Sensation & Perception Christopher DiMattina , PhD. Today’s topics. Attentional blink Scene perception Neurobiology of attention. Attentional Blink. Attention in time. We talked about spatial attention last lecture

mira
Télécharger la présentation

Attention & Scene Analysis 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Attention & Scene Analysis 2 PSY 295 – Sensation & Perception Christopher DiMattina, PhD

  2. Today’s topics • Attentional blink • Scene perception • Neurobiology of attention PSY 295 - Grinnell College - Fall 2012

  3. Attentional Blink PSY 295 - Grinnell College - Fall 2012

  4. Attention in time • We talked about spatial attention last lecture • How are attention resources deployed in time? PSY 295 - Grinnell College - Fall 2012

  5. RSVP task • Rapid serial visual presentation • Show stimuli in rapid succession – need to detect two different target stimuli – say an ‘X’ and a white letter • Can detect a single target at rate of 8-10 targets/sec PSY 295 - Grinnell College - Fall 2012

  6. RSVP task PSY 295 - Grinnell College - Fall 2012

  7. Attentional blink • If T2 appears 200-300 msec after T1, and we correctly detect T1, we are impaired at detecting T2 PSY 295 - Grinnell College - Fall 2012

  8. Fishing metaphor • Imagine fishing in a dirty stream (boots, tires, etc…) • Dip net into water when you see a fish • If another fish swims by while you are busy with the first fish, you will miss it! PSY 295 - Grinnell College - Fall 2012

  9. Good performance for 100 msec • This corresponds to getting two fish in your “attention net” PSY 295 - Grinnell College - Fall 2012

  10. First-person shooter games • Video game players do better than other people. Any thoughts as to why? PSY 295 - Grinnell College - Fall 2012

  11. Green & Bavelier (2003) • Studied visual selective attention in first person shooter video-game players (VGP) and non-video game players (NVGP) • VGPS outperformed NVGP’s at varied spatial and temporal attention tasks PSY 295 - Grinnell College - Fall 2012

  12. Flanker compatibility task • Subjects detect diamond or square in one of six circles • Compatible or incompatible figure shown outside • Compatibility benefit disappears for hard task in NVGPs PSY 295 - Grinnell College - Fall 2012

  13. Enumeration task • VGPS were better at telling how many squares briefly flashed PSY 295 - Grinnell College - Fall 2012

  14. Better attention over space • VGPs better at telling which of six arms a target was flashed • Advantage for all eccentricities PSY 295 - Grinnell College - Fall 2012

  15. Question • Can you think of a possible flaw with this experiment? PSY 295 - Grinnell College - Fall 2012

  16. Training NVGPs • Two groups of NVGP’s were trained with two different games – tetris (control) and a first-person shooter game • First person shooter game subjects improved in attention tasks PSY 295 - Grinnell College - Fall 2012

  17. Play first-person shooter games for better attention PSY 295 - Grinnell College - Fall 2012

  18. Scene Perception PSY 295 - Grinnell College - Fall 2012

  19. Gist perception • How do we know this is a kitchen before we see the individual objects (sink, oven, etc…)? PSY 295 - Grinnell College - Fall 2012

  20. Ensemble statistics PSY 295 - Grinnell College - Fall 2012

  21. Ensemble statistics PSY 295 - Grinnell College - Fall 2012

  22. Two pathways PSY 295 - Grinnell College - Fall 2012

  23. Non-selective pathway quickly computes scene properties • People can monitor stream of images @ 100 msec per image • Can move eyes to one of two pictures containing an animal in only 120 msec • Can discriminate natural from man-made scenes with only 19 msec of exposure to scene • 20-50 msec to recognize just one object PSY 295 - Grinnell College - Fall 2012

  24. Image statistics • May be using very low-level properties of scenes like spatial frequency content to discriminate categories • Similar semantic categories of scenes have similar spatial frequency components and low-level structure PSY 295 - Grinnell College - Fall 2012

  25. Similar categories, similar structure PSY 295 - Grinnell College - Fall 2012

  26. We are good at recognizing scenes PSY 295 - Grinnell College - Fall 2012

  27. Which ones did you see? PSY 295 - Grinnell College - Fall 2012

  28. Answers PSY 295 - Grinnell College - Fall 2012

  29. Good at gist, bad with details PSY 295 - Grinnell College - Fall 2012

  30. Neurobiology of Attention PSY 295 - Grinnell College - Fall 2012

  31. Attention modulates brain activity from O’Craven et al (1997) PSY 295 - Grinnell College - Fall 2012

  32. Attention modulates brain activity • Enhances neural responses to attended features PSY 295 - Grinnell College - Fall 2012

  33. Attention modulates brain activity PSY 295 - Grinnell College - Fall 2012

  34. Single cell effects • Attention biases competition by shrinking RF around attended object in V4 and IT (Moran & Desimone1985) PSY 295 - Grinnell College - Fall 2012

  35. McAdams & Maunsell • For single stimulus in RF, attention has multiplicative effect on tuning curves PSY 295 - Grinnell College - Fall 2012

  36. Spatial modulation PSY 295 - Grinnell College - Fall 2012

  37. Disorders of attention PSY 295 - Grinnell College - Fall 2012

  38. Parietal lobe lesions • Patients with right parietal lobe lesions neglect the left half of visual space. Not due to basic sensory deficits. PSY 295 - Grinnell College - Fall 2012

  39. Neglect PSY 295 - Grinnell College - Fall 2012

  40. Neglect • May be object-centered as well as spatial PSY 295 - Grinnell College - Fall 2012

  41. Extinction • Can only deploy attention to bad field if there are no competing objects in the good field • Objects in good field “extinguish” those in the bad field • Perhaps a milder form of neglect PSY 295 - Grinnell College - Fall 2012

  42. Balint syndrome • Bilateral parietal lesions • Cannot disengage attention without blinking • Can only attend to one object at once (simultagnosia) PSY 295 - Grinnell College - Fall 2012

More Related