Motor planning under temporal uncertainty is suboptimal when the gain function is asymmetric

Area of Science:

• Cognitive Neuroscience
• Motor Control
• Decision Making

Background:

• Optimal action planning requires considering action-related gains/losses and motor output variability.
• Previous studies on human action planning optimality yield conflicting results due to variations in movement types and gain/loss functions.

Purpose of the Study:

• To investigate the optimality of human timing strategies in action planning.
• To test how different gain function configurations affect decision-making under motor uncertainty.

Main Methods:

• Utilized a coincident timing task with constant energetic cost.
• Compared participant timing strategies against a Bayesian model maximizing expected gain.
• Examined four gain function configurations, two symmetric and two asymmetric.

Main Results:

• Suboptimal timing strategies were observed under asymmetric gain functions, particularly those with high gain and risk of zero gain.
• Participants exhibited risk-seeking behavior, responding closer to the zero-gain threshold.
• Good agreement between the model and actual performance was found under symmetric gain functions.

Conclusions:

• Human decision-making under motor output uncertainty has limitations influenced by the gain function's configuration.
• Asymmetric gain functions pose challenges to optimal action planning, leading to risk-seeking strategies.