1. Development of Number
Concepts in Children

2. Overview Why is this relevant?
How do infants process numbers at 5-6 months?
Basis for experimental design: Infants have a tendency to look longer at unexpected results and objects

3. Small Numbers System Capabilities in adults Boundaries in infants
Can infants enumerate physical objects and action?

4. Karen Wynn (1998)
Experimental Variation
1+1= 1 or 2
2-1= 1 or 2

5. Additional Controls 1+1= 2 or 3 3-1= 2 or 3 1-1= 0 or 1
Rotating Platform Control and Object Tracking Theory

6. Conclusions Accumulator Theory Object File
But what about larger numbers?

7. Fei Xu (2003)
Disc Test

8. Disc Test Area Control Contour Line Control Weber Ratio
2 vs. 4 (small number discrimination)
4 vs. 8 (large number discrimination)
2 vs. 3 ?

9. Results
4 vs. 8

10. Results
2 vs. 4

11. Conclusions Number Estimation System
Weber fraction
Output of object tracking system inhibits number estimation system
Object Tracking
Limit 3, maybe 4 objects

12. Interpretations Error extent of data Task Difference
Props
General Conclusion:
Accumulator vs. object tracking in small numbers
Number estimation for large numbers