Investigating habituation to a stimulus

Question 1

Independent variable

Answer 1

number of pokes

Question 2

dependent variable

Answer 2

retraction time

Question 3

Other variables to be controlled (3)

Answer 3

• Replication using snails of approx same size and age - –
• Equal handling history
• Drying out

Question 4

Equipment (4)

Answer 4

• 1 giant African land snail
• 1 dampened cotton wool bud
• Clean firm surface
• Stop watch

Question 5

Outline method

Answer 5

Collect one giant African land snail, and place it on a clean, firm surface. Allow the snail to get used to its new surroundings for a few minutes until it has fully emerged from its shell. Dampen a cotton wool bud with water. Firmly touch the snail between the eye stalks with the dampened cotton wool bud and immediately start the stopwatch. Measure the length of time between the touch and the snail being fully emerged from its shell once again, with its eye stalks fully extended. Repeat the procedure in step 3 for a total of 10 touches, timing how long the snail takes to re-emerge each time. Record your results in a suitable table. Present your results in an appropriate graph.

Question 6

Possible evaluation issues (4)

Answer 6

• Snails already handled before the experiment may not react in the same way
• Determining when a snail has fully emerged
• Lack of moisture may encourage snail to stay more in its shell
• Measuring eye stalk length instead