How does task complexity affect reaction time?

• A. Increased complexity decreases reaction time.
• B. Complexity has no effect.
• C. Complexity only affects accuracy, not reaction time.
• D. Increased complexity increases reaction time.

Answer: (D)

When a task has more information to process, the brain needs more time to sense the stimulus, decide what to do, and prepare the movement. Reaction time is the interval from stimulus to response, so increasing complexity adds processing steps and choices, which lengthens this interval. This is why more complex tasks lead to longer reaction times. A helpful way to think about it is that more possibilities or features to evaluate slow down the decision and motor preparation stages. Practice can reduce overall times by making some decisions more automatic, but the fundamental relationship remains: greater complexity tends to increase reaction time.