1. Language & Decision Making
J. Lauwereyns, Ph.D.
Professor
Faculty of Arts and Science
Graduate School of Systems Life Sciences
Kyushu University

2. Language: Unique to humans?

3. Evolution and Physiology of Language
Human language is different because it is more productive
can produce new signals to represent new ideas
Chimpanzees can learn to communicate using sign language or symbols, but different from human language
symbols used to request but rarely to describe
seldom recombine in new combinations
say more than they understand, the opposite of children

4. Language as a Special Module
Humans have evolved with something that enables them to learn language easily
Chomsky and Pinker: a language acquisition device
children learn language with ease, including children of deaf parents
deaf children learn sign or invent one of their own
not likely a separate module since most language areas used for other functions, e.g., memory, music perception
intelligence may be by-product of language

6. Broca vs Wernicke

8. Broca’s Aphasia Also called non-fluent aphasia
severe deficits in language production caused by damage to Broca’s area, and other cortical and subcortical structures
difficulty pronouncing, gesturing and writing as well as understanding complex speech
uses and understands nouns and verbs more easily than closed-class words, e.g., prepositions, pronouns
ignores grammar and relies on inferences
but, can usually recognize when something is wrong with sentence even if they cannot correct it

9. Wernicke’s Aphasia Also called fluent aphasia
caused by damage to left temporal cortex
seriously impaired language comprehension
difficulty finding the right word and trouble recalling names of objects
grammatical but often nonsensical speech
perhaps because can’t “find” words due to rapid speech
but, can pronounce clearly, fluently and rapidly

10. Wernicke:
Comprehension,
Meaning
Broca:
Production,
Syntax

11. What about language on the left?

12. What about language on the left?
Lateralization of Brain Function
Two hemispheres are not mirror images of each other
left hemisphere controls right side of body
right controls left side
taste and smell input to same side
Lateralization is the specialization of labor between the two hemispheres
left hemisphere specialized for language
right specialized for complex visual-spatial tasks and synthetic processing

13. Handedness and Language Dominance Right handedness a heritage
10% of people are left-handed or ambidextrous
90% of prehistoric drawings show tools in right hand
most chimps and other primates are right handed
Left handers
have equal as well as left or right hemisphere dominance for speech
if right is dominant, left hemisphere contributes more to spatial perception
Corpus Callosum is thicker for greater communication

14. Not quite as famous as
Sir Edmund Hillary,
but…

15. Where does Corballis get his idea?
Corticol control of manual movements
Primates acquiring sign language
The mirror system in monkeys
Left hemisphere for speech and hands
Deaf use sign languages with full syntax
Nonverbal gestures during speech
FOXP2 gene mutated about 200,000 years ago

16. FOXp2

17. Where does Corballis get his idea?
Corticol control of manual movements
Primates acquiring sign language
The mirror system in monkeys
Left hemisphere for speech and hands
Deaf use sign languages with full syntax
Nonverbal gestures during speech
FOXP2 gene mutated about 200,000 years ago

18. The mirror system
Ventral premotor
area –
monkey homologue
of Area 44 in
frontal cortex,
that is,
Broca’s Area
Studied by
Rizzolatti and co.

20. The mirror system Neurons in ventral premotor area
…activated both when the subject performs an action and when the subject observes someone else perform the same action
Abstract action representation
This system likely plays a role both in recognising and planning actions (“thinking about actions”)

21. Importance of the mirror system?
Understanding action?
Origins of language?
Empathy?
Morality?
(some other day…)

22. On reasoning and decision making

23. On reasoning and decision making
More complex with language
Consider context
Imagine different scenarios…

24. Most basic structure for decision making…
Response
Stimulus
Stimulus – Response Matrix

25. Signal detection theory

26. Bias

27. Consider different decision contexts…

28. Consider different decision contexts…

29. Consider different decision contexts…

30. Bias

31. Sensitivity

32. Sensitivity

33. Ways to improve sensitivity…

34. Ways to improve sensitivity…

35. Ways to improve sensitivity…

36. How does it really work?

39. General increase

40. General increase: Prospective, additive
Bias in anticipatory activity
Linearly enhances sensory activity
Response = Input + Reward Bias
Prefrontal cortex, basal ganglia
Superior colliculus

43. Improved discrimination

44. Improved discrimination: Synergistic, multiplicative
Sensory properties
Non-linearly enhanced by reward
Response = Input * Reward Gain
Prefrontal cortex, parietal cortex
Superior colliculus

45. Dopamine

46. Dopamine

47. Dopamine Excitation Synergistic, multiplicative Disinhibition
Sensitivity
Prospective,
additive
Bias

48. How do we process conflicts?
Paradox
Immediate reward
versus Delayed gratification

49. The classic: Stroop James Ridley Stroop, inventive priest
Present participants with a word printed in a certain colour
GREEN
Name the colour
Interference from irrelevant word
RT: Incompatible > Neutral > Compatible
Evidence of conflict

50. fMRI study:McDonald et al
Using a “cued Stroop” task
Trial begins with
“word” : read the word
“colour”: name the colour
Task instruction changes trial by trial
Separate effects
Instruction-related activity
Response-related activity

51. Response- related activity RED GREEN related activity Instruction- RED
Congruent
stimulus
Incongruent
stimulus
COLOUR
NAMING
RED
GREEN
related activity
Instruction-
“red”
“red”
RED
GREEN
WORD
READING
“red”
“green”

53. Interpretation In DLPFC:
Stronger activity in “colour” trials than in “word” trials
Effects of task instruction, but not congruency
Especially before target onset (during preparation)
In ACC:
Stronger activity in “incongruent” trials as compared to “congruent” trials
Effects of congruency, but not task instruction
Especially after target onset, or even after response

54. Conclusions Dorsolateral prefrontal cortex
Seems important for representing the task instruction
Ordering what to do
Anterior cingulate cortex
Seems involved in situations of conflict
Performance monitoring
Evaluating what you do