The document summarizes a thesis defense on the neural substrates of conditional reasoning. It presents hypotheses that conditional reasoning activates bilateral fronto-temporoparietal regions for formal and semantic processing, while causal conditional reasoning specifically activates left fronto-parietal regions. It also hypothesizes differences based on content (causal vs abstract) and domain (physical vs social). The study found left lateralized activation for causal reasoning and right lateralized activation for abstract reasoning. It also found right lateralized activation for social reasoning and left fronto-parietal activation for physical reasoning.

1. Sylvie Pelletier
YORK UNIVERSITY
Thesis Defense
December 07, 2011

2. Introduction
Objectives & Hypothesis
Research Design and Method
Results
Discussion
Conclusion

3. Mental Mental Dual-
Model Multiple Reasoning
Logic (Johnson-Laird
system Systems
(Rips, 1994) (Evans, 2003) (Goel, 2007)
& Byrne, 1991)

4. Main Effect Content Domain
Prado et al (in press) Reverberi (2010); Canessa et al.
Goel (2000)
(2005)
Abstract/Non-
Causal
Conditional Bilateral parietal-frontal Physical:
Reasoning pathway
Left linguistic system
Left posterior
parietal cortex, Left
precentral
gyrus, medial frontal
gyrus Causal Social
Left hemispheric
Right-hemispheric
frontotemporal
prefrontal cortex
system

5. Objectives:
Examine the neural substrates of conditional reasoning with various types of
conditional content and causal conditional content with fMRI
Hypothesis:
1. Main effect:
I. Conditional reasoning: Bilateral fronto-temporo-parietal activation
(visuo-spatial/formal and syntactic/semantic processing)
II. Causal conditional reasoning: Left fronto-parietal activation
(syntactic/semantic processing)
2. Content effect:
I. Content reasoning: Left fronto-temporal activation(syntactic/semantic
processing)
II. Abstract reasoning: (visuo-spatial/formal processing)
3. Domain effect:
I. Physical reasoning: Leftfronto-temporal (syntactic/semantic processing)
II. Social reasoning: Right lateral prefrontal cortex, medial and superior
frontal, and parietal activation (social cognition)

6. CONTENTS (N=96)
Causal (n=72) Abstract (n=24)
Physical-causal (n=24) Social-causal (n=48) If TTTTTT are KKKKKK,
then YYYYYY are AAAAAA.
MP If the brake is depressed, then the car will If Ray misses Wendy, then he TTTTTT are KKKKKK,
(n=24) slow down. will visit her. YYYYYY are AAAAAA
The brake is depressed, Ray misses Wendy,
The car slows down Ray visits Wendy
Reasoning
T Tasks
MT If the car is out of gas, then it will stall. If Vic pressures Jim, then Jim If JJJJJJ are EEEEEE, then
A (n=80) (n=24) The car didn't stall, will be stressed. NNNNNN are PPPPPP.
S The car wasn't out of gas. Jim isn’t stressed, NNNNNN aren't PPPPPP
K Vic didn’t pressure Jim. JJJJJJ aren’t EEEEEE.
S AC If the key is turned, then the car will start. If Tim is charitable, then he will If BBBBBB are TTTTTT, then
(n=16) The car starts, help the poor. VVVVVV are NNNNN.
The key was turned. Tim helps the poor, VVVVVVV are NNNNNN,
Tim is charitable. BBBBBB are TTTTTT.
DA If it is raining, then the road will be wet. If Pam sees a stranger, then she If RRRRRR are FFFFFF, then
(n=16) It isn't raining, will cry. JJJJJ are TTTTTT.
The road isn't wet. Pam doesn’t see a stranger, RRRRRR aren't FFFFFF,
She doesn't cry. JJJJJJ aren't TTTTTTT.
If the brake is depressed, then the car will slow If Tim is charitable, then he will If KKKKKK are YYYYYY,
Baseline down. help the poor. then OOOOOO are TTTTTT.
Tasks The foundation is cracked, Joe loves Ann, MMMMMM are KKKKKK
(n=16) It rains Amy hangs out with Ellen JJJJJJ are EEEEEE

7. Means and Standard Deviations on Measures of Response Times and Accuracy
Across 12 Participants
Content Effect (n=96) Domain Effect (n=72)
Causal Abstract Physical Social
(n=72) (n=24) (n=24) (n=48)
MP n=24 99.65 (0.012) 100.00 (0.000) n=18 100.00 (0.000) 99.31 (0.0241)
MT n=24 87.50 (0.2344) 77.78 (0.2595) n=18 90.28 (0.2508) 84.72 (0.2243)
Scores
(%) AC n=16 7.37 (0.2336) 11.11 (0.2312) n=12 6.25 (0.2165) 8.48 (0.2522)
DA n=16 12.15 (0.2707) 20.45 (0.2697) n=12 12.50 (0.3108) 11.81 (0.2415)
Baseline n=16 97.97 (0.0159) 93.75 (0.1131) n=12 100.00 (0.000) 97.97 (0.0159)
MP n=24 1324 (324) 1317 (385) n=18 1302 (361) 1346 (356)
MT n=24 1682 (554) 1912 (754) n=18 1605 (627) 1759 (574)
RT
(ms) AC n=16 1484 (471) 1703 (641) n=12 1358 (444) 1611 (616)
DA n=16 1506 (306) 1617 (676) n=12 1515 (322) 1497 (390)
Baseline n=16 1564 (649) 1735 (738) n=12 1431 (632) 1696 (683)

8. 1. Main effect of
conditional reasoning
2. Main effect of causal conditional reasoning

9. 1. Interaction causal > abstract 2. Interaction abstract > causal
3. Simple effect causal 4. Simple effect abstract

10. 1. Interaction physical >
social
2. Interaction social >
physical

11. Main effect of conditional reasoning:
Right and left hemispheric activity in fronto-temporo-
parietal
Integration of both syntactic language-based activity
and visuo-spatial processing
Main effect of causal conditional reasoning:
Left frontoparietal activation left inferior frontal
Syntactic/semantic processing

12. Causal reasoning:
Left-lateralized activation of lateral frontal structures
and structures near the temporo-parietal junction (TPJ).
Linguistic processing and semantic integration.
Abstract reasoning:
Right lateralized activation of occipito-parieto-temporal
regions
Spatial manipulation and internal representation of
symbols

13. Social reasoning:
Right lateralized activation of the inferior frontal gyrus
and the insula.
Social cognition & empathy
Physical reasoning:
Left fronto-parietal activation
Non-social conditional reasoning structures
Lexico-semantic processing

14. Behavioral results
Poor accuracy for invalid forms
Confusing instruction
Use of force-choice responses (true or false):
If the brake is depressed, then the car will slow down.
The car slows down
∴ The brake is depressed.

15. Reasoning is a fractionated cognitive system that
relies on various neural pathways
Content
Domain
Future studies: Brain lesion studies