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Habituation is a reduced response to a repeated, inconsequential stimulus. In a suitable snail context, a defined withdrawal or re-extension measure can be recorded after the centre’s approved gentle stimulus. Use the specified welfare procedure, consistent stimulus and recovery arrangements; increasing force to obtain a more dramatic response defeats both the ethical design and the comparison.
Video by John Witton. Use the demonstration alongside this lesson’s specification reference and written explanations.
Viewing focus: Design a controlled repeated-stimulus investigation
After watching, attempt these questions before opening the answers. You can also use the written lesson below.
After watching 1: What must remain comparable across repeated trials?
The defined stimulus and observation conditions. Otherwise the response trend may reflect changing treatment or measurement.
After watching 2: What do ten trials on one snail represent?
Repeated observations of one biological individual. Repeated-measures information and independent replication differ.
What you'll be able to do
Habituation is a reduced response to a repeated, inconsequential stimulus. In a suitable snail context, a defined withdrawal or re-extension measure can be recorded after the centre’s approved gentle stimulus. Use the specified welfare procedure, consistent stimulus and recovery arrangements; increasing force to obtain a more dramatic response defeats both the ethical design and the comparison.
State exactly what is timed, such as the duration from withdrawal to a defined re-extension endpoint. Control temperature, hydration, handling, stimulus interval and observation conditions. An animal that has become inactive because of unsuitable conditions is not automatically demonstrating learning.
Repeated trials on one animal reveal a response time course for that individual. They are correlated observations, not independent animals. Use additional appropriately independent individuals if the question concerns a population pattern, and choose an analysis that recognises the repeated-measures design.
Record every planned trial and the actual stimulus interval. Changes in observer endpoint judgment can imitate a shortened response. An appropriate comparison and recovery or response-capacity checks can help evaluate fatigue or sensory adaptation. No single control necessarily rules out every alternative explanation.
A declining withdrawal duration can be consistent with habituation in the stated design. A response returning after a rest or a suitable changed stimulus can strengthen the interpretation, but recovery alone can also occur after fatigue or adaptation. Evaluate the full evidence and avoid claiming a neural mechanism from timing alone.
A shorter observed duration does not necessarily mean that the animal’s muscles work faster or that every sensory receptor has changed. State which response component was measured. Limit the conclusion to the tested conditions and describe a specific follow-up that distinguishes competing explanations while respecting the organism’s welfare.
Attempt these problems on paper before opening the worked reasoning. Explain your steps as well as giving a final answer.
Common mistakes to avoid
Key takeaways
Question 1: After a rest, the same animal again shows a 28 s response. What does this contribute to interpretation?
Useful recovery evidence, not a unique proof of one underlying mechanism.
Check the assessed scope and practical or mathematical requirements.
An external explanation or interactive activity to use alongside the lesson. It may include extension material.
Close the notes and answer from memory. Revisit any explanation you cannot yet reconstruct.
Test yourself
Answer a few questions, then review anything you missed.
Start with the quiz above to check the key ideas. You can also choose another topic from the practice library.