Decoupling sensory from decisional choice biases in perceptual decision making

Area of Science:

• Cognitive Neuroscience
• Psychology
• Decision Science

Background:

• Understanding perceptual decision making is crucial, yet the distinct roles of sensory and decisional processes remain unclear, even in basic tasks.
• Choice bias, a tendency to favor one option, can stem from sensory evidence bias or independent preference, complicating interpretation.

Purpose of the Study:

• To differentiate between sensory and decisional biases in perceptual decision making.
• To investigate how varying response mappings influence these biases in a simple discrimination task.

Main Methods:

• Human participants performed a two-alternative symmetric perceptual discrimination task.
• Task instructions were manipulated to alter the response mapping between perception and alternative categories.
• Signal detection theory was employed to model observed biases.

Main Results:

• A significant majority of participants (30 out of 32) exhibited sensory biases.
• A notable portion of participants (15 out of 32) also displayed decisional biases.
• Decisional biases were accurately modeled as criterion shifts within a signal detection theory framework.

Conclusions:

• Perceptual decision making is demonstrably influenced by both sensory and decisional biases, even in simplified tasks.
• The study successfully decoupled sensory and decisional influences by manipulating task instructions.
• Findings highlight the complex interplay of evidence processing and response selection in decision-making.