QCAA Psychology - Deregowski (1972)

Recall the main focus of Experiment 1 by Deregowski (1972).

• A construction task

• Depth perception apparatus designed by Gregory

• The impossible two-pronged trident

• A replication of Hudson's (1960) test of 2D versus 3D perception

• Split-type drawings versus perspective drawings

Recall the main focus of Experiment 2 by Deregowski (1972).

• A construction task

• Depth perception apparatus designed by Gregory

• The impossible two-pronged trident

• A replication of Hudson's (1960) test of 2D versus 3D perception

• Split-type drawings versus perspective drawings

Recall the main focus of Experiment 3 by Deregowski (1972).

• A construction task

• Depth perception apparatus designed by Gregory

• The impossible two-pronged trident

• A replication of Hudson's (1960) test of 2D versus 3D perception

• Split-type drawings versus perspective drawings

Recall the main focus of Experiment 4 by Deregowski (1972).

• A construction task

• Depth perception apparatus designed by Gregory

• The impossible two-pronged trident

• A replication of Hudson's (1960) test of 2D versus 3D perception

• Split-type drawings versus perspective drawings

Recall the main focus of Experiment 5 by Deregowski (1972).

• A construction task

• Depth perception apparatus designed by Gregory

• The impossible two-pronged trident

• A replication of Hudson's (1960) test of 2D versus 3D perception

• Split-type drawings versus perspective drawings

Identify the term given to a drawing that displays all the necessary characteristics of a depicted object at the same time.

• Perspective drawing

• Split-style drawing

• Orthogonal drawing

• Line drawing

Answer explanation

Split-style drawings show the essential characteristics of an object, similar to net drawings of 3D objects.

Recall the type of cue that was the most important for depth perception, according the findings of Deregowski (1972) in Experiment 4.

• Height in visual field

• Size constancy

• Relative size

• Interposition

Answer explanation

In experiment 4, 2D perceivers changed the spot of light so that it was set at the same apparent depth, regardless of whether they were asked to place it above the hunter, the antelope or the elephant.

3D perceivers, however, moved the spot of light so that it appeared further away from themselves when placing it on the elephant than when playing it on the hunter and the antelope.

These results did not apply when the image was replaced with one that only included relative size.

Identify the research method used by Deregowski (1972).

• Longitudinal study

• Repeated measures design

• Quasi-independent group design

• Cross-sectional study

Answer explanation

Deregowski (1972) used a quasi-independent group design. The method is a quasi experiment because the researcher was unable to manipulate the independent variable (culture of the participants, Western or African).

In Deregowski's (1972) construction task (Experiment 3), participants were shown a simple three-pronged trident and an impossible figure called the "two-pronged trident."

Identify the dependent variable from Experiment 3.

• How long the participants viewed each image.

• Whether participants saw the image in 2D or 3D.

• How accurately participants could redraw each image.

• How long it took the participants to replicate the images.

Answer explanation

In Experiment 3, the dependent variable was the length of time participants viewed the images.

To see the image, participants lifted a timed flap. They were able to look at the image for as long as they wanted, but they could not copy it during this time.

It was predicted that 2D perceivers would require less viewing time than 3D perceivers. 

Explain what an impossible figure is, referring to the findings of
Deregowski's (1972) Experiment 3.

Answer explanation

Example Model Answer

Impossible figures work by exploiting perceptual cues so that we are forced to see images that should not be possible, or should not be able to exist.

The two-pronged trident was an impossible figure because the left side of the image shows three prongs while the right side shows the base splitting in two. As a result, the 3D perceivers tried to interpret the 2D image in a 3D way which is not possible, confusing them and therefore they needed a longer viewing time.

1 mark - description of an impossible figure

1 mark - description of the results of Experiment 3, with specific reference to the image used