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Reaction terminology

Reaction Time vs Response Time

The terms are sometimes used interchangeably, but in motor-control research a useful distinction is between the delay before movement begins and the time required to complete the movement.
Updated 2026-08-17 · Research-linked educational guide · Free browser tests

Key takeaways

On this page

  1. A simple terminology model
  2. Why a simple click test is different
  3. Aim tests combine multiple stages
  4. Why different websites use different words
  5. How Reaction Lab labels results

A simple terminology model

Suppose a target appears and you must move a mouse cursor to it. There is first a period where you perceive the target and prepare the movement. Then there is a movement phase where the cursor travels to the target.

In many motor-control contexts, the first interval is called reaction time and the second is called movement time. Their sum can be described as total response time or task-completion time.

Why a simple click test is different

If your finger is already resting on the mouse button and the only instruction is “click when green,” there is almost no aiming movement. The recorded browser interval is therefore close to stimulus-to-click response latency.

It still includes the physical button action and hardware/software delay, so even this narrow number is not a pure neural conduction measurement.

Aim tests combine multiple stages

When a target appears at a new location, you must detect it, choose or plan a movement, move the pointer or finger and successfully select the target. Target size and distance affect the movement component.

This is why an Aim score should not be compared directly with a Classic score. One deliberately includes target acquisition while the other tries to minimize it.

Why different websites use different words

Everyday writing often treats “reaction time” and “response time” as synonyms. Human-computer interaction, psychology, sport science and engineering may define them differently depending on what is being measured.

Always read the test method. The label matters less than knowing exactly when the timer starts and what event stops it.

How Reaction Lab labels results

Reaction Lab uses “reaction time” as the familiar user-facing term for stimulus-to-input latency in its reaction modes. Aim and moving-target modes are broader performance tasks because movement and accuracy are integral to the result.

The Stats dashboard is most useful when you compare the same mode over time rather than combining unlike tasks.

Common questions

Are reaction time and response time the same?

They are often used interchangeably in everyday language, but some research separates reaction time from subsequent movement time.

Does an aim trainer measure reaction time?

Partly, but it also measures movement/target acquisition and accuracy.

What does Reaction Lab time?

For reaction modes, it timestamps the interval between the browser’s go event and your registered input. Hardware latency remains part of the result.

COMPARE REACTION WITH AIMTry Classic and Aim to feel the difference between a near-stationary response and target acquisition.
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Research and further reading

  1. Woods et al. — Factors influencing the latency of simple reaction time
  2. Fitts' law and human movement / pointing performance
Research links are provided for context. Reaction Lab is an entertainment and personal benchmarking site, not a medical, neurological, vision, hearing or fitness diagnostic service.