Penny is using cats and parrots in her experiment. Penny houses each animal alone and only gives them their daily food every evening. Her independent variable is the species. She thinks that parrots will share food because they are social animals whereas cats live on their own. To test this, two animals of the same species are put together with a small bowl of food every afternoon.

Mark scheme

Marking points from the official mark scheme (May/June 2018). The mark or mark type is shown in brackets.

1. 1 mark for identifying way to operationalise. 1 mark for elaboration/justification e.g. how it would be quantified.
2. food sharing could be operationalised as how much food each animal eats;
3. e.g. by counting the number of pieces of food each animal takes;
4. e.g. by weighing the animals
5. see whether one animal waits for the other/see if they both get something to eat;
6. e.g. by timing how long before each animal starts eating;
7. 1 mark for identifying an appropriate ethical problem. 1 mark for explanation.
8. As it was in the evening they were food deprived for almost 24 hours when they were tested (in the afternoon);
9. this might make them more aggressive;
10. this could be distressing for the animals;
11. 1 mark for explanation, which can be explicit comparison or detail.
12. Cats are solitary anyway, so being kept on their own is not a problem/parrots are social animals so being isolated from other parrots could be distressing;
13. 1 mark for reason (may be generic). Plus 2 marks for linked detail.
14. animals respond to people; she therefore needs to be hidden;
15. cats and parrots are domestic animals; so they would be likely to respond to people;
16. so that she does not act as an uncontrolled variable/distract their normal behaviour/reduce validity;
17. 2 marks for a fully operationalised non-directional hypothesis, correctly using cats and parrots, and saying how food sharing will be measured
18. 1 mark for a non-directional hypothesis which is not operationalised
19. Cats and parrots will differ in the time they spend sharing food (2)
20. There will be a difference in the number of pieces of food shared between the cats and parrots (2)
21. There will be a difference in food sharing between the cats and parrots (1)
22. There will be a difference in helpfulness between the cats and parrots (1)
23. There will be a difference in food sharing between animal species (1)