Numerosity Comparison in Three Dimensions in the Case of Low Numerical Values

Area of Science:

• Cognitive Psychology
• Visual Perception
• Psychophysics

Background:

• Number processing for small quantities relies on 'number sense', consistent with Weber's law.
• Previous research indicated 3D numerosity overestimation primarily at higher numerical values.
• The current study investigates 3D numerosity perception at lower numerical values.

Purpose of the Study:

• To examine if 3D numerosity overestimation occurs at low numerical values.
• To determine if the Weber ratio adheres to Weber's law for 3D stimuli compared to 2D.
• To differentiate mechanisms for perceiving numerosity and density.

Main Methods:

• Observers compared pairs of 2D and 3D stimuli to identify the one with more elements.
• The method of constants was employed to collect data.
• Calculations included point of subjective equality (PSE) and just noticeable difference (JND).

Main Results:

• Overestimation of 3D numerical values was confirmed even at small quantities.
• The Weber fraction was observed to adhere to Weber's law within the tested range.
• Findings support the existence of separate mechanisms for numerosity and density perception.

Conclusions:

• 3D numerosity overestimation is present even for small numerical values.
• Weber's law accurately describes the relationship between stimuli and perception in 3D numerical tasks.
• This research contributes to understanding the distinct neural processes underlying visual number perception.