1. Stephanie Lidd and Jamie Tauber
Sources of Flexibility in Human Cognition: Dual Task Studies of Space and Language
Linda Hermer-Vasquez, Elizabeth S. Spelke and Alla S. Katsnelson
Stephanie Lidd
and
Jamie Tauber

2. Human Navigation Abilities
Two unique features
Capable of dead reckoning
Great flexibility
Disorientation
Can reorient themselves after disorientation
How?

3. Cheng Experiments (1986)
Tested rats’ abilities to find food after disorientation
Rats went to the correct corner and the geometric equivalent at equally high rates
Despite differences in non-geometric cues (e.g. brightness, pattern, and odor)
Conclusion: Rats reorient in accordance with environment shape (geometric module)

4. Hermer, Spelke: Orientation Abilities in Children (18-24 Months)
Similar to Cheng’s experiment
Searched for hidden object in all white room, then room with one blue wall
Searched both corners equally in all white room
Failed to use non-geometric property (blue wall) as a way of navigation (like adult rats)

5. Results for Cheng and Hermer &Spelke

6. Hermer and Spelke: Adult Disorientation
Conducted same experiment using adults
Adults checked geometrically equivalent corners in white room
Were able to use the blue wall as a way of orienting themselves and finding the object (used non-geometric)

7. Hermer (1994): Disorientation in Children (3-7 years)
Described position of the object as behind colored wall or to the left or right
Children 4+ were successful in describing the objects position behind the wall
Children 6+ were able to describe the position as ‘left’ or ‘right’ of the wall

8. Hermer (1997) Spatial Language in Children 5-7 years
Tested children’s abilities to use spatial language
Correlation between spatial language and ability to use non-geometric landmarks to locate objects

9. Causation Between Spatial Language and Development of Spatial Performance Possibilities
Three possibilities
Independent, but developmentally linked
Depend on a common factor
Development of spatial language produces change in spatial relations

10. Experiment 1 Similar to Cheng’s Experiment
White room and room with a blue wall
Tested again in each room with ‘verbal shadowing’: repeating a tape-recorded prose
Non-shadowing conditions had ‘white noise’ playing
Disoriented (spun around) before each trial

11. Diagram of Chamber Used

12. Results

13. Experiment 2A Visual Experimentation with 3 conditions
Rhythmic Verbal: repetition of ‘na’
Rhythmic Non-verbal: tapping out pattern
Verbal: Repetition of prose
Computer program showing grids varying numbers of ‘T’s and target ‘L’
Subjects had to determine presence or absence of target ‘L’

14. Results

15. Experiment 2B
Like Experiment One, with modified disorientation for last 8 subjects
Results:
Non-shadowing subjects produced higher accuracy in recognition
Shadowing subjects showed decline in accuracy
Subjects searched with high frequencies in correct and geometrically equivalent corners

16. Experiment 2C Identical with 2B except with Rhythmic shadowing
Results:
Shadowing subjects searched the correct corner with higher frequency than the rotationally equivalent corner
Higher accuracy than verbal shadowing
Non-shadowing produced same, accurate results

17. What’s the Difference?
Rhythmic and Verbal were equally distracting, yet rhythmic was more accurate
Verbal shadowing may interfere with geometric and non-geometric combination process or
Combination process independent, but verbal shadowing may interfere with their ability to detect or remember the non-geometric landmark

18. Experiment 3
Verbally shadowing subjects with a simplified version of tests
Instead of being hidden to the left or right, was hidden on top of the walls
Walls were removed from chamber to remove the geometric cues

19. Results Subjects located the object with high accuracy
Landmark-appropriate search was higher in Experiment 3 than in the verbal shadowing conditions of Experiments 1 and 2b
Showed adults used non-geometric cues, despite disorientation

20. Experiment 4
Like Experiment 3, except the object was placed to the left or right of the wall
If verbal shadowing impairs the encoding of non-geometric information only in reorientation tasks, then both subjects should successfully find the object
If verbal shadowing impairs the conjoining of geometric and non-geometric information then non-shadowing subjects should find the object but shadowing subjects should not.

21. Results

22. Conclusions
Spatial memory system found in children and adult rats is present in adult humans
Language plays a role in the conjoining of geometric and non-geometric information