Cognitive psychology: Case study 4: Movement-produced stimulation in the development of visually guided behaviour

Cognitive psychology

Case study 4: Movement-produced stimulation in the development of visually guided behaviour

Author: Held and Hein (1963)

Key term: Kitten Carousel

Is visual perception learned or inherited? If an animal is deprived of a sensory experience, in this study physical movement in an artificial environment, can it adapt when placed in an normal environment?

Aim/Hypothesis: To test if self produced movement is necessary for visually guided behaviour (eg. walking). In this experiment, to see if a kitten needs to see and move for itself in an environment to be able to develop normal movement, such as paw placement. 

Method: Laboratory experiment

Variables:

• Independent variables: 

1. The two different pairs of kittens X and Y. 
2. The passive kitten and active kitten.

• Dependent variables:

1. Kittens response to tests based on visually guided behaviour.

Design: Independent measures, because each kitten on preforms in one condition on the test.

Participants and sampling technique: 10 pairs of kittens, each taken from a different litter.

Apparatus: 

1. Kittens are kept in a cage with no light with their mother and litter mates during non-experimental time.
2. 'Exposure' apparatus: Striped environment and a carousel. In the pair, the active kitten is attached to a harness and allowed to walk freely around the carousel. The movement from the active kitten is transferred to the passive kitten, who is put in a gondola to restrain leg movements.

Controls:

• All kittens were exposed to the same environment and did the same tests.
• All kittens were kept in the same living conditions.

Procedure:

1. The 10 pairs of kittens were divided into two groups: Group X: Eight pairs. Group Y: Two pairs.
2. Group X: Reared in darkness from birth until one kitten from the pair was able to coordinate and walk around, which was around 8-12 weeks old.
3. Group Y: Reared in darkness for 2 weeks from birth, then from 2-10 weeks were put in exposed environment (carousel) for 3 hours a day. They were put in a double gondola; so head movement was allowed but nothing else.
4. All 10 pairs were then placed in the carousel for 3 hours a day.One kitten (active) was allowed to walk and the other (passive) was not. During non-experiment time they were put back in the light-less cage.
5. After around 33 hours of exposure to the carousel, each kitten was tested with six different tests. 3 were the main tests and 3 were additional.

         Main tests

• Visually guided paw placement - Kitten was held above a table and slowly moved towards it. Normal kittens would put their paws to touch the surface.
• Avoidance of visual cliff - A bridge with a shallow drop on one side and a deep drop, with invisible glass on the top so the kittens don't fall, on the other. A normal kitten will avoid the deep drop and walk onto the shallow surface.
• Blink to an approaching object: The experimenter will quickly bring his hand towards the kitten's face but stopping before actually touching the kitten. Normal kittens will blink.

         Additional tests

• Pupillary reflex to light: The kittens pupil should shrink when a light is shined in their eyes.
• Tactual placing response: Similar to paw placement test. When a normal kitten is touching a vertical surface it will move its paws to touch the horizontal surface.
• Visual pursuit of moving object: When the experimenter moves his hand in front of the kitten their head and eyes should follow the movement.

Group X: Paw placement repeated 6 times after carousel exposure and when one kitten from the pair (active) passed the paw placement they were tested on the visual cliff. 

Group Y: Paw placement repeated 6 times, but when active kitten passed only the active kitten was tested on the visual cliff.  Only tested after 6 weeks (126 hours) on the kitten carousel.

Findings: 

• All kittens responded normally to additional tests (pupillary reflex, tactual placement,  visual pursuit).
• The active kittens in group X passed all the main tests (paw placement, blinking, visual cliff), whereas none of the passive kittens in group X passed.
• All the group Y passive kittens failed the paw placement and visual cliff tests.
• After 48 hours in a normal, well lit free environment, all the kittens performed normally on all tests, showing no after effects of the experiment.

Conclusion: Visually perception is not all inherited, self produced movement is needed for normal visually guided behaviour.