Children Getting Lost: Language, space, and the development of cognitive flexibility in humans

1. Children Getting Lost:Language, space, and the development of cognitive flexibility in humans

2. Spatial Re-orientation • Human adults re-orient using both spatial and non-spatial cues • Young children and animals are limited to spatial cues • Hypothesis: Use of non-spatial cues is causally linked to the development of language production abilities • Language production ability > Non-spatial reorientation ability

3. Testing Rats (Cheng, 1996) • Foraging task - 3 hidden food locations specified by odors and varying brightness throughout the cage • Cage rotated to misalign with rat’s orientation

4. Testing Rats (Cheng, 1986)

5. Testing Rats (Cheng 1996) • Contrary to expectations, rats relied on the 3D geometry of the cage, but NOT “non-geometric clues” • Conclusion: adult rats rely strictly on geometry for reorientation tasks

6. Hermer and Spelke (1994, 1996) test human reorientation

7. Adult search results Child search results • Adult subjects utilize both geometric and non-geometric clues for reorientation • Children utilize only geometric clues for reorientation

8. Experiment 1 • Designed to determine: • At what age children being performing like adults in reorientation tasks • Which cognitive mechanism(s) enable adult reorientation abilities

9. Experiment 1 • Prior knowledge: first purpose of this experiment was thus to confirm that children of 3-4 years of age would fail to conjoin geometric and non-geometric information to solve this task • to test whether subjects who rely on non-geometric information in this task are truly reorienting using that information (like the rats in previous experiments)

10. Experiment 1 - Purpose • Prove that children aged 3-4 years will fail to use both geometric and non-geometric clues to solve task • Prove that older children would combine clues to solve task, similar to human adults and different from young children/adult rats • Determine the age at which children use a blue wall as a landmark for direct spatial memory

11. Experiment 1 - Task • 8 males, 8 females between 3-4 years old • 10 males, 5 females ages 5-6 • Subjects are tested in a rectangular chamber with no windows or sources of noise • White noise generator • Overhead camera • Child gets to choose a toy to search for in this ‘game’

12. Experiment 1 - Design/Results • Design • Direct Landmark condition: object hidden behind fabric in a corner, child spun 5 times with eyes covered and told to search for toy • Variable: one test uses blue was as a DIRECT clue to the object’s location, an INDIRECT clue for the other test • Results: • Older subjects tended to search the absolutely correct corner • Children searched geometrically appropriate locations

13. Experiment 1 - Results 5.5-6.5 yrs., indirect 3-4 yrs., direct 5.5-6.5 yrs., direct 3-4 yrs., indirect

14. Experiment 1 - Discussion • Children were strikingly successful at using non-geometric (i.e. the blue wall) information to locate a hidden object in the Direct Landmark task • Color is being used in addition to ‘left, right, across from’ etc • Prior studies showed children 3-4 years perform like young kids or ADULT RATS • Transition occurs during ages 5 to 7

15. Experiment 1 - Discussion • 2 groups of children put in reorientation tasks, blue wall used as a direct cue and indirect clue • Children from 3 to 6.5 years of age consistently perceived and remembered the location of the blue wall and used its location to guide their search for the object

16. Experiment 2 • Test for correlation of other skill development with flexible reorientation • Dependent variable: reorientation task performance • Independent variables: age, nonverbal intelligence, digit span, spatial memory span, reorientation performance in all-white room, comprehension/production of “left-right” and “above/behind” phrases

17. Methodology • 10 boys, 14 girls, mean age 5.8 years • Reorientation task:

18. Language production task

19. Language comprehension task

20. Digit/serial visuospatial span task • Repeat a number series • Visuospatial:

21. Reorientation task results All white room One red wall

22. Reorientation task results

23. Experiment 3 • Correlation between mind and spoken language • To determine if children exhibit a search pattern similar to adult rats • Requires a combination of landmark and sense information • Subjects also gave language production trials • Children ages 6-7 years (paid of course)

24. Experiment 3 • Circle of 9 plastic cups with a dwarf statue as an inherent landmark • Child watches object become hidden in cup to landmark’s right • Child’s eyes + ears covered, toy AND landmark are moved • Children expected to show ability similar to adults rats to confine their search to the cups nearest the landmark

25. Experiment 3 - Subjects are told: `He [the dwarf] likes to play a game in which you and he go into a room together, a toy is hidden, your eyes and ears are covered, and then you have to find the toy.' - After the toy is moved, the experimenter says, `Where's the toy? Go get it', and recorded the subject's subsequent search

26. Experiment 3 - Results • The subjects did NOT search randomly for the object, and searched in the correct location more often than not • The 2 locations on either side of the dwarf after being moved were searched more frequently • Subjects learned to confine searches to locations next to the landmark • Resembled adults rats who searched for hidden food in proximal regions to a movable landmark array (Biegler and Morris, 1993, 1996)

27. Experiment 3 - Results • Error: not enough information was gained to link language production capabilities in question with several subjects, who did not show an ability to search a location above chance • Human adults suggest LR production plays a role in moving object searches

28. Conclusions • Previous experiments (Hermer-Vzquez et al., 1999) have shown that verbal interference impairs reorientation in adults • Interference = “verbal shadowing”

29. Conclusions • Verbal abilities may increase speed, efficiency, and combination of other skills

30. Problems • Failure to reproduce correlation between LR production and performance in experiment 3 gives cause for doubt • Extremely small sample sizes • Failure to clearly account for LR and spatial differences