This document discusses research showing that the visual system has the capacity to estimate numerosity, and that numerosity is an independent primary visual property like color or motion. The researchers found that perceived numerosity is susceptible to adaptation in a similar way as primary visual properties. They adapted subjects to stimuli with either small or large numbers of dots, and found that adaptation to small numbers increased apparent numerosity, while adaptation to large numbers decreased it. This suggests numerosity is analyzed independently in the visual system and is prone to adaptation like other primary properties.

1. A visual sense of number
2010. 9. 17

2. A visual sense of number
• Burr ， Current biology,2008
• All primary visual properties are susceptible to
adaption.
• If numerosity was a primary property, like color or
motion, it too should be prone to adaption.

3. Instruction
• Evidence exists for a nonverbal capacity for the apprehension
of number, in humans and in other primates.
• Here, we show that perceived numerosity is susceptible to
adaptation, like primary visual properties of a scene.
• Apparent numerosity was decreased by adaptation to large
numbers of dots and increased by adaptation to small numbers.
• The effect depending entirely on the numerosity of the
adaptor.

4. Instruction
• The perception of large numbers is assumed
to require slower and more cognitive
processes, like counting. Here, by showing
that perceived numerosity is susceptible to
adaptation, like primary visual properties of a
scene, such as color, contrast, size, and speed,
We suggest that the visual system has the
capacity to estimate numerosity and that it is
an independent primary visual property.

5. Assumption
• All primary visual properties are susceptible
to adaptation. If numerosity was a primary
visual property, like color or motion, it too
should be prone to adaptation.

6. Methods
• Subjects were adapted to a stimuli for 30
seconds. Then they are asked to do a
numerosity jugdement, deciding which stimuli
had more dots.

9. Exp.1

11. Exp.1

12. Result
• Adaptation to small numbers increased
apparent numerosity, and adaptation to large
numbers decreased apparent numerosity.

13. Exp.2
• Dose adaption actually affected by other
factors? (density, contrast, parallel or orthog
size, shape)

14. Result
• Adaptation occurs for both high and low
adaptation numbers and is independent of
pixel density, contrast, color, shape, or other
visual properties.

15. Further Discussion
• Neurones that are related to visual sense of
number are demonstrated . They are probably
adaptable. Vision has formidable built-in
computational powers, allowing for
approximately constant perception of object
size, shape, and color. It should come as no
surprise that it can provide approximate
estimates of number.

16. Thanks for your attention.