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Brain Structures and Functions – Hemispheric Specialization Contralaterality

Brain Structures and Functions – Hemispheric Specialization Contralaterality Left Brain – receives input from right side of the body, and controls right side of body. Right Brain - receives input from left side of the body, and controls left side of body. point of fixation.

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Brain Structures and Functions – Hemispheric Specialization Contralaterality

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  1. Brain Structures and Functions – Hemispheric Specialization Contralaterality Left Brain – receives input from right side of the body, and controls right side of body. Right Brain - receives input from left side of the body, and controls left side of body.

  2. point of fixation

  3. Brain Structures and Functions – Hemispheric Specialization Language Capabilities – Left Hemisphere Broca and Wernicke– mid-to-late 1800s WADA Test– sodium amytal Estimates of Left Hemisphere Language Dominance 85-90% of RH Males 79% of Females 70% of LHers Work by Sperry (during 1960s) Split-brain patients – severed corpus callosum Spatial Capabilities – Right Hemisphere Sperry found that split-brain patients could draw better with left hand.

  4. Right Hemisphere Dominance of Visual-Spatial Functions

  5. Chimeric Face

  6. Attention

  7. "[Attention] is the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thoughts... It implies withdrawal from some things in order to deal effectively with others." William James (1890) used to: concentrate select information inhibit information monitor a goal set

  8. Alerting and Arousing

  9. The Orienting Reflex – Automatic attention via an unexpected stimulus Habituation – tendency for attention to a stimulus to decrease over time

  10. From Marcus et al. 1999 7 mo. old kids habituate to “ga ti ga” Tested on: wo fe wo (i.e., consistent) wo wo fe (i.e., inconsistent) - learned an ABA rule

  11. The Capacity of Attention Events that require a lot of attention Engaging in conversation Studying for an exam Calculating the solution to a math problem Events that require little attention Eating food Walking Washing the dishes

  12. Attention as a Pool of Resources Divided Attention – The Dual Task Primary Task- characteristics manipulated Cond. 1 Cond. 2 Secondary Task - performance measured RT to a tone

  13. Attention as a Pool of Resources Divided Attention – The Dual Task Kantowitz et al., 1983 - flight simulator primary task- flying Cond. 1 = takeoff Cond. 2 = middle of flight Cond. 3 = landing secondary task - respond to a tone

  14. Attention as a Pool of Resources Divided Attention – The Dual Task Kantowitz et al., 1983 - flight simulator primary task- flying Cond. 1 = takeoff Cond. 2 = middle of flight Cond. 3 = landing – RT to tone secondary task - respond to a tone

  15. Posner’s Spotlight of Visual Attention (Posner et al., 1978, 1980) Cue Target + + Valid Trial Invalid Trial Neutral Trial 80% 20% + + + +

  16. Posner’s Spotlight of Visual Attention (Posner et al., 1978, 1980) Cue Target Results + + Valid Trial Invalid Trial Neutral Trial + + + +

  17. 70 ms from Magnum et al. 1993

  18. visual search RT in ms Display Size

  19. RT in ms Display Size distracters similar = serial search distracters dissimilar = parallel search

  20. Information Selection Cocktail Party Problem- you have to attend to one conversation and ignore others.

  21. Basketball Movie

  22. Information Selection Laboratory Tasks Involving Selection Dichotic Listening Task Shadowing Task Interesting findings - REA for verbal stimuli - LEA for pitch - word monitoring - shows hemispheric dominance

  23. Normal subjects

  24. Split-brain patients

  25. Information Selection – Dichotic Listening When does selection occur? i.e., to what degree has information been processed before it has been selected for or against? Late? identify words loudness of voice sex of voice Early? Message 1 Message 2

  26. Information Selection When does selection occur? Cherry (1953) - shadowing task participants report from unattended ear Message 1 – selected for Message 2 – selected against

  27. Information Selection When does selection occur? Cherry (1953) – shadowing task participants report from unattended ear Message 1 – selected for Message 2 – selected against filter earlylate physical content characteristics

  28. Information Selection When does selection occur? Cherry (1953) - shadowing task participants report from unattended ear Message 1 – selected for Message 2 – selected against filter earlylate physical content characteristics

  29. Information Selection When does selection occur? Cherry (1953) - shadowing task participants report from unattended ear participants reported physical characteristics e.g., sex of voice, speed of message they could not report high-level perceptual information language (e.g., German vs. English) a word that was repeated 35 times – reported in Moray (1959) supports early selection model Message 1 Message 2

  30. Information Selection When does selection occur? Moray (1959) - shadowing task participants could report their name Message 1 Message 2 can ID name can’t ID word repeated 35 times?

  31. Activation Metaphor Threshold for Identification mental representations for concepts Other Concepts Your Name

  32. Activation Metaphor Threshold for Identification mental representations for concepts Other Concepts Your Name

  33. Activation Metaphor Threshold for Identification mental representations for concepts Other Concepts Your Name

  34. Activation Metaphor Threshold for Identification mental representations for concepts Resting Level Other Concepts Your Name

  35. Treisman's Attenuation Model Treisman (1960) shadowing task eliminated physical difference b/w messages same speaker used for both At some point, the content of message switched attendunattend "In the basket, she had peanut butter..." "sandwiches and chocolate brownies" participants switched ears This suggests that when they have to, people select late

  36. Attention as a Pool of Resources Divided Attention – The Dual Task Primary Task- characteristics manipulated Cond. 1 Cond. 2 Secondary Task - performance measured RT to a tone

  37. Multimode Model of Attention - Johnston & Heinz (1978) One can select early (based on physical characteristics) or late (based on content), but the later one selects, the more resources are used. Dual task primary task = shadow a message secondary task= respond to flash of light

  38. Multimode Model of Attention - Johnston & Heinz (1978) One can select early (based on physical characteristics) or late (based on content), but the later one selects, the more resources are used. Dual task primary task = shadow a message secondary task= respond to flash of light RT to light flash 1 message = +60 ms over baseline 2 messages - meaning and physical difference = +80 ms over baseline 2 messages – physical difference only = +120 ms over baseline 2 messages – meaning difference only= +170 ms over baseline message 1 – selected for filter – early fewer resources message 2 – selected against

  39. Multimode Model of Attention - Johnston & Heinz (1978) One can select early (based on physical characteristics) or late (based on content), but the later one selects, the more resources are used. Dual task primary task = shadow a message secondary task= respond to flash of light RT to light flash 1 message = +60 ms over baseline 2 messages - meaning and physical difference = +80 ms over baseline 2 messages – physical difference only = +120 ms over baseline 2 messages – meaning difference only= +170 ms over baseline message 1 – selected for filter – late more resources message 2 – selected against

  40. 20-50 ms after tone adapted from Woldorf et al. (1993)

  41. Information Selection Inhibition Negative priming 3 7 4 4 7 7 2 9 9 9 4 3 4 4 1 5 6 2 5 5 8 2 4 2 4 4 2 3 Supports late selection b/c identity must occur for negative priming to occur

  42. negative priming

  43. negative priming and attentional selection

  44. negative priming – basic effect

  45. negative priming – semantic effects

  46. negative priming – semantic effects

  47. negative priming and attentional selection supports late selection – meaning is processed as # of items to be processed increases selection tends to be earlier

  48. Information Selection Inhibition Negative priming Neumann & DeSchepper (1991) effect of perceptual load - # distracters negative priming suggests inhibition is resource dependent

  49. Neumann & DeSchepper (1991) - perceptual load control –low load low load high load 3 4 7 4 2 7 4 3 7 2 7 9 1 7 9 4 9 3 9 4 2 3 9 4 1 4 5 4 5 4 3 8 5 6 2 5 2 5 1 7 8 2 4 2 4 3 5 2 4 2 4 3 4 3 5 1

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