Decision urgency invigorates movement in humans.

Area of Science:

• Cognitive Neuroscience
• Decision Science
• Motor Control

Background:

• Previous research in trained monkeys suggested urgency regulates decision-making and motor control for reward optimization.
• It remained unclear if this mechanism was species-specific or dependent on extensive practice.

Purpose of the Study:

• To investigate if a unified regulation of decision timing and action vigor by urgency exists in naive human subjects.
• To determine if this mechanism is independent of practice and contributes to reward rate optimization.

Main Methods:

• Seventeen naive human volunteers performed a reach decision task across multiple sessions and trial blocks.
• Blocks varied in difficulty, encouraging either risky or conservative choices, with participants motivated to maximize reward rate.
• A computational model combining sensory information with an urgency signal was used to analyze behavioral data.

Main Results:

• Decision accuracy criterion decreased within trials, and decisions were faster but less accurate in high-urgency (fast) blocks.
• These effects were more pronounced in the second session, suggesting learning but not practice-dependent establishment of the core mechanism.
• Movement vigor (arm and eye) systematically increased with decision duration, and decision policies predicted movement kinematics.

Conclusions:

• A practice-independent mechanistic link unifies human decision timing and action vigor control.
• This unified control, regulated by urgency, optimizes the rate of reward in a reach decision task.
• The findings extend the urgency-based reward optimization hypothesis to naive human subjects.