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IGCSE · Cambridge (CIE) · 0610

Interpret supplied reflex and deliberate response times

Calculate means while keeping pathway and measurement evidence distinct.

Section 14.1 · Coordination and response

Coordination and response pathway · 14.1

Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked

Before you begin

  • Recall cell membranes, diffusion, sensitivity and the difference between cells, tissues and organs.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

How is a mean of three supplied response times calculated?

What you will learn

  • Compare like timing measurements
  • A time value does not identify every pathway

Interpret supplied reflex and deliberate response times

Invented stimulus-to-response records: compare means using the same endpoint. Latency includes several stages and is not a direct single-neurone speed measurement. Original teaching model.

Invented stimulus-to-response times / ms
ModelTrial 1Trial 2Trial 3Mean
Automatic150170160160
Deliberate320340330330
Neural model reference
FeatureMeaning
Automatic model150, 170, 160 ms → mean 160 ms
Deliberate model320, 340, 330 ms → mean 330 ms
Difference170 ms in these supplied records
LimitA fast value alone does not establish reflex identity

Compare like timing measurements

The invented paper records show automatic-model response times of one hundred and fifty, one hundred and seventy and one hundred and sixty milliseconds. The deliberate-model records are three hundred and twenty, three hundred and forty and three hundred and thirty milliseconds. Each set uses the same stated timing definition from stimulus onset to the recorded response.

The automatic-model mean is one hundred and sixty milliseconds; the deliberate-model mean is three hundred and thirty milliseconds. The difference is one hundred and seventy milliseconds. These values support the comparison that the stated automatic model is faster in these records, not a rule that every reflex in every organism has the same latency.

A time value does not identify every pathway

A fair practical comparison would require the same response endpoint and comparable conditions, with repeated measurements and attention to timing resolution. Prior anticipation, different movement distances or different endpoint detection can affect recorded times. A timer record combines detection, communication and effector-response components rather than directly measuring only impulse speed along one neurone.

The supplied models already state whether initiation is automatic or deliberate. An isolated fast value without pathway information cannot identify a reflex by itself. Use the numerical records to compare the stated models, then retain the biological definition of automatic and rapid stimulus-response coordination instead of inventing a diagnostic or universal cutoff.

Pause and explain

Which comparison follows the supplied records?

Put the idea to work

Worked example

Calculate the automatic-model mean from 150, 170 and 160 ms.

Show the worked solution
  1. Add the three times to obtain 480 ms.
  2. Divide by three measurements.

Answer The automatic-model mean is 160 ms.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Calculate both supplied means and their difference.

Give me a hint

Sum each set separately and divide by three.

Compare my reasoning
  1. Automatic: (150+170+160)/3 = 160 ms; deliberate: (320+340+330)/3 = 330 ms.
  2. Difference: 330−160 = 170 ms.

Means: 160 ms and 330 ms. The automatic model is 170 ms faster in these supplied records.

Look for these in your work

  • Calculate both means
  • Restrict the comparison to supplied records
2 · Independent

A second paper set gives automatic times 120, 140 and 130 ms and deliberate times 260, 280 and 270 ms. Find the two means and difference.

Give me a hint

Use the same mean calculation.

Compare my reasoning
  1. Automatic mean: 390/3 = 130 ms; deliberate mean: 810/3 = 270 ms.
  2. Difference: 270−130 = 140 ms.

130 ms versus 270 ms, a 140 ms difference in this second supplied set.

Look for these in your work

  • Calculate each mean
  • State difference with time units
3 · Transfer

Does a stimulus-to-movement time directly measure only the impulse speed along one neurone?

Give me a hint

Several components contribute and speed also needs distance.

Compare my reasoning
  1. Detection, communication and effector response contribute.
  2. A single-neurone distance and travel interval are not isolated.

No. The recorded latency combines several stages and supplies no isolated single-neurone distance/time measurement, so it does not directly establish that impulse speed.

Look for these in your work

  • Identify combined stages
  • Separate time and speed

Common mistakes

  • Reporting a total as a mean.
  • Calling the whole response time a direct impulse-speed measurement.
Recall without your notes

What can you explain now?

Which comparison follows the supplied records?

Compare with the explanation

160 ms versus 330 ms; automatic model is faster here

The comparison is limited to the stated records.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Calculate the two means and explain why timing alone does not identify every reflex pathway.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Biology

Course scope and assessment

780 sequenced lessons provide 2340 guided, independent and application problems in characteristics, classification, cells, organisation, specimen size, membrane transport, biological molecules, enzymes, plant and human nutrition, plant transport, circulatory systems, the heart, blood vessels, blood, disease transmission, body defences, immunity, gas exchange in humans, respiration energy uses and investigations, aerobic respiration, anaerobic respiration and recovery, excretion in humans, coordination and response, sense organs, hormones, homeostasis, tropic responses, drugs, asexual reproduction, sexual reproduction, sexual reproduction in plants, sexual reproduction in humans, sex hormones in humans, sexually transmitted infections, chromosomes, genes and proteins, mitosis, meiosis, monohybrid inheritance, variation, adaptive features, selection, energy flow, food chains and webs, nutrient cycles, population, community, ecosystem, population-growth phases, food supply, habitat destruction, pollution, conservation, biotechnology and genetic modification. 61 of 61 syllabus sections have linked teaching and staged practice. The earlier inheritance overview remains introductory, and the monohybrid pathway develops the relevant Core and Supplement requirements. This is not full programme completion or guaranteed exam readiness. Written practice is self-checked.

StudyForA · Learn with understanding

Original teaching content and links to official sources. Check your exam year and qualification before using a resource.