Visually guided movement with increasing time-on-task: Differential effects on movement preparation and movement...

Area of Science:

• Cognitive psychology
• Human factors
• Neuroscience

Background:

• Cognitive control is susceptible to fatigue from prolonged task engagement (time-on-task, ToT).
• Motor response planning and preparation are particularly vulnerable to ToT effects.
• Limited research exists on ToT's impact across distinct movement phases.

Purpose of the Study:

• To investigate the specific effects of ToT on different phases of mouse-pointing movements.
• To determine if ToT-induced deficits stem from orientation or alertness impairments.
• To analyze changes in movement preparation, execution, and error rates with increasing ToT.

Main Methods:

• Three experiments using a mouse-pointing task with varying target configurations and cuing conditions.
• Systematic assessment of movement initiation (preparatory phase) and execution times.
• Measurement of movement errors and analysis of response time trade-offs.

Main Results:

• Movement initiation slowed, while movement execution accelerated with increasing ToT.
• Overall response time remained constant, but the movement time/error ratio decreased, indicating impulsivity.
• Increased movement errors suggested imprecise execution, particularly in Experiment 2.
• Experiment 3 ruled out orientation and phasic alerting deficits, identifying decreased tonic alertness.

Conclusions:

• Time-on-task fatigue significantly impacts motor control by slowing preparation and speeding execution, leading to increased errors.
• The primary mechanism appears to be a reduction in tonic alertness, rather than orientation or phasic alerting deficits.
• Findings highlight the vulnerability of cognitive control processes to fatigue during prolonged tasks.