Perceptual Errors Support the Notion of Masking by Object Substitution.

Area of Science:

• Cognitive Psychology
• Visual Perception

Background:

• Object substitution masking (OSM) is a phenomenon affecting visual perception.
• Understanding the underlying mechanisms of OSM is crucial for visual processing research.

Purpose of the Study:

• To investigate the effect of object substitution masking (OSM) on perceptual errors in reporting target orientation.
• To determine if OSM's mechanism involves increased noise or a substitution process by comparing it to noise masking.

Main Methods:

• Two experiments were conducted, comparing different masking conditions (four-dot trailing mask, simultaneous-noise mask).
• Responses were analyzed using mixture regression models and Bayesian inference.
• Factorial variation of masks was employed in the second experiment.

Main Results:

• OSM increased guessing rates and reduced target representation precision, particularly when the mask trailed the target.
• Noise masks also affected guessing and precision, but differently from OSM.
• An interaction between OSM and noise masks in Experiment 2 suggested shared underlying mechanisms.

Conclusions:

• OSM is largely a result of a substitution process.
• Evidence suggests that masking can increase noise levels when substitution does not occur.
• The mechanism of OSM is not solely attributable to increased noise.