SingaporeSports ScienceSyllabus dot point

How does an athlete take in information, decide and act, and what affects reaction time?

Describe the information-processing model (input, decision making, output, feedback) and the factors affecting reaction time

A focused answer to the O-Level ESS outcome on information processing. The input-decision-output-feedback model, memory, and the factors affecting reaction time, with a ruler-drop calculation.

Generated by Claude Opus 4.89 min answerUpdated 2026-06-06

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this dot point is asking
The answer
Examples in context
Try this

What this dot point is asking

SEAB wants you to describe the information-processing model and the factors affecting reaction time. The central idea is that skilful performance is not just movement: the brain takes in information, decides what to do, sends the command to the muscles, and learns from the result, all in a fraction of a second.

The answer

The information-processing model

Performing a skill follows four stages.

Input: the performer gathers information from the environment through the senses (sight, hearing, touch and the sense of body position). A receiver watches the ball, the server and the court.
Decision making: the performer selects the right response by comparing the input with past experience stored in memory, then choosing a movement.
Output: the chosen response is sent to the muscles, which carry out the movement.
Feedback: information about the result returns to the performer, from their own senses (intrinsic feedback) and from a coach or scoreboard (extrinsic feedback), and is used to improve the next attempt.

The role of memory

Decision making relies on memory. The short-term memory briefly holds the current input; the long-term memory stores past experiences and learned movements. Comparing the input with the long-term store lets a skilled performer recognise a situation and respond quickly.

Reaction time and related terms

Reaction time is the time between a stimulus appearing and the start of the response (hearing the gun to first movement).
Movement time is the time to complete the movement once it has started.
Response time is the total of the two: reaction time plus movement time.

Factors affecting reaction time include age, the number of possible choices (more choices slow it), the intensity and clarity of the stimulus, fitness and alertness, and practice or experience.

Calculating reaction time from a ruler-drop test

A coach measures reaction time with the ruler-drop test. The athlete catches the falling ruler after it drops $0.20\ \text{m}$ . Find the reaction time using $d = \tfrac{1}{2}gt^2$ with $g = 9.8\ \text{m s}^{-2}$ . Work in steps.

Step 1: Write the equation and rearrange for time

The ruler falls under gravity, so $d = \tfrac{1}{2}gt^2$ . Rearranging for time:

t = \sqrt{\frac{2d}{g}}

Step 2: Substitute the values

t = \sqrt{\frac{2 \times 0.20}{9.8}}

Keep distance in metres and $g$ in metres per second squared.

Step 3: Simplify inside the square root

t = \sqrt{\frac{0.40}{9.8}} = \sqrt{0.0408}

Step 4: Take the square root and interpret

t = 0.20\ \text{s}

So the athlete's reaction time is about $0.20$ seconds. A smaller drop distance would give a shorter reaction time. Show the rearrangement, the substitution and the units to earn full marks.

Examples in context

Example 1. A goalkeeper facing a penalty. The keeper inputs the striker's run-up and body shape, decides which way to dive by comparing it with experience in memory, outputs the dive, and afterwards uses feedback (whether they saved it) to refine future dives. The whole loop happens in well under a second.

Example 2. A sprinter on the blocks. The sprinter's start depends on reaction time, the gap between the gun and the first push. By practising the response to the start signal until it is almost automatic, they shorten reaction time, then movement time governs the rest of the race.

Try this

Cue. List the four stages of the information-processing model in order. (Input, decision making, output, feedback.)
Cue. Define reaction time, movement time and response time. (Reaction time: stimulus to start of movement; movement time: time to complete the movement; response time: the two added together.)
Cue. Explain why an experienced player usually has a faster decision-making stage than a beginner. (They have a larger store of past experiences in long-term memory to compare the input against, so they recognise the situation and select a response more quickly.)

Exam-style practice questions

Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Original6 marksDescribe the four stages of the information-processing model, using a batsman facing a delivery in cricket as your example.

Show worked answer →

Input: the performer takes in information from the environment through the senses. The batsman watches the bowler's arm, the ball's flight, speed and spin.

Decision making: the performer selects the correct response by comparing the input with past experience stored in memory. The batsman decides which shot to play.

Output: the chosen response is carried out by the muscles. The batsman plays the shot.

Feedback: information about the result returns to the performer, from their own senses (how it felt, where the ball went) and from others (the coach). The batsman uses it to adjust the next shot.

What markers reward: the four stages in the correct order (input, decision making, output, feedback), each correctly described and tied to the batsman example.

Original5 marksDefine reaction time and state three factors that affect it. Explain how a sprinter could improve their reaction time at the start.

Show worked answer →

Reaction time: the time taken between the presentation of a stimulus and the start of the performer's response.

Factors (any three): age (it lengthens with age), the number of choices (more possible responses lengthen it), the intensity of the stimulus (a louder or clearer signal shortens it), fitness and alertness, and prior experience or practice.

A sprinter can improve their reaction time at the start by practising responding to the starting signal repeatedly, so the response becomes faster and more automatic, and by staying alert and focused on the gun in the set position.

What markers reward: a correct definition of reaction time, three valid factors, and a sensible method (practising the response to the start signal, heightened alertness) to improve it.