Pointing, looking at, and pressing keys: A diffusion model account of response modality

Area of Science:

• Cognitive Psychology
• Computational Neuroscience
• Human-Computer Interaction

Background:

• Accumulation of evidence models precisely explain perceptual decision-making across various domains.
• Ratcliff's diffusion model is widely applied to two-choice tasks with key-press responses.

Purpose of the Study:

• To investigate the universality of the diffusion model across different response modalities.
• To examine how stimulus discriminability and response mapping influence decision-making parameters.

Main Methods:

• Two experiments using a letter-discrimination task were conducted.
• Participants used eye movements, key presses, or touchscreen pointing for responses.
• The diffusion model was fitted to response time and accuracy data.

Main Results:

• Model fits supported the hypothesis of a shared decision mechanism regardless of response modality.
• Drift rates varied with stimulus presentation duration, reflecting decision evidence accumulation.
• Response execution time was modulated by the specific response modality employed.

Conclusions:

• The diffusion model effectively captures perceptual decision-making across diverse response methods.
• Decision-making processes are separable from response execution mechanisms.
• Understanding these parameters offers insights into cognitive and motor control systems.