Response bias in numerosity perception at early judgments and systematic underestimation.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Numerical Cognition

Background:

• Mental number representation links nonsymbolic visual stimuli to symbolic numerical magnitudes.
• This representation is known to follow a logarithmic scale, leading to systematic underestimation in numerosity judgments.
• Understanding the temporal dynamics of this process is crucial for clarifying its underlying mechanisms.

Purpose of the Study:

• To investigate the temporal dynamics of numerosity perception.
• To examine how response deadlines influence numerosity judgments.
• To determine the role of feedback in calibrating mental number representations.

Main Methods:

• Four experiments utilized the response-deadline Signal-detection Theory (SAT) procedure.
• Participants judged the numerosity of dot arrays, comparing them to a standard of 50.
• Response bias at early decision stages and underestimation at later stages were analyzed.

Main Results:

• Temporal dynamics revealed a response bias in early numerosity decisions.
• Late decisions showed systematic underestimation of dot quantities.
• Providing feedback significantly reduced the magnitude of underestimation across experiments.
• Experiment 3 demonstrated increased underestimation errors in the absence of feedback.

Conclusions:

• Feedback is essential for the accurate calibration of mental number representations.
• The temporal dynamics of numerosity perception highlight distinct early and late decision processes.
• These findings contribute to a deeper understanding of how humans perceive and represent numerical information.