Biology · Glossary

What is Reaction time?

Definition 33.5 Primary & Middle School Biology · Chapter 33 — The Brain in Command

The loop is fast but not instant: report, decision and order each take their share. The delay between a signal and the body’s response is the reaction time — for a simple task (catch, press, grab), about a fifth of a second in a practiced person, a little more in children.

Examples

Example 33.7 (Why the passenger seat gasps first)

A fifth of a second seems nothing — until speed multiplies it. A car at highway speed covers about 7m7\,\mathrm{m} during a fifth-of-a-second reaction: the driver has not yet touched the brake, and the car has crossed a classroom. Reaction time is why distances between cars exist, and why a driver’s attention is a safety organ.

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