Interpret supplied reflex and deliberate response times
Calculate means while keeping pathway and measurement evidence distinct.
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
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.
| Model | Trial 1 | Trial 2 | Trial 3 | Mean |
|---|---|---|---|---|
| Automatic | 150 | 170 | 160 | 160 |
| Deliberate | 320 | 340 | 330 | 330 |
| Feature | Meaning |
|---|---|
| Automatic model | 150, 170, 160 ms → mean 160 ms |
| Deliberate model | 320, 340, 330 ms → mean 330 ms |
| Difference | 170 ms in these supplied records |
| Limit | A 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?
Worked example
Calculate the automatic-model mean from 150, 170 and 160 ms.
Show the worked solution
- Add the three times to obtain 480 ms.
- Divide by three measurements.
Answer The automatic-model mean is 160 ms.
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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.
Calculate both supplied means and their difference.
Give me a hint
Sum each set separately and divide by three.
Compare my reasoning
- Automatic: (150+170+160)/3 = 160 ms; deliberate: (320+340+330)/3 = 330 ms.
- 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
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
- Automatic mean: 390/3 = 130 ms; deliberate mean: 810/3 = 270 ms.
- 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
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
- Detection, communication and effector response contribute.
- 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.
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.
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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.