Haber and Levin (2001) The Independence of Size Perception and Distance Perception (2 Experiments)

Topic 8—Perception 

Haber and Levin (2001) The Independence of Size Perception and Distance Perception (2 Experiments)

Experiment 1:

Aims:

• To see if objects could be separated into 2 categories.
• 1st category—those that have very little variation in size between different examples of the same object (token invariant).
• 2nd category—those that have a lot of variation between different examples of the same object (token variable).
• To see whether participants were able to accurately estimate the size of objects categorised as token invariant fro memory compared to objects categorised as token variable.

Procedure:

• Began with a list of 50 items they thought would be very familiar to university students.
• Then they looked for 10 different examples of each of these items that they could measure.
• This resulted in a list of 30 familiar items that they could find enough examples of to develop a list of measurements taken from different sources.
• 109 male university students from Chicago, USA were given a questionnaire to complete. 
• The questionnaire included the list of objects with space beside each one for participants to estimate how tall each object was in feet & inches.
• The participants were asked to guess the size of all 50 of the original familiar objects, but the study mainly focused on the 30 that had been categorised as invariant/variable.

Results:

• 15 out of 30 of the objects in the list of familiar items showed a high degree of difference in measurements between the 10 samples they found—these were labeled as token variable items.
• The other 15 items on the list showed very little variation between the different samples—these were labeled as token invariant items.
• Haber & Levin found that participants showed a good degree of accuracy in the size estimates they gave of all the familiar objects on the questionnaire.
• They also found that participants showed more variation in their estimates for the token variable than. The token invariant items on the questionnaire.
• They found that the participants were most accurate at estimating the size of objects that had little variation in size between different examples—those that were token invariant.

Conclusions:

• The results suggest that when people are familiar with objects that naturally vary very little in size from one example to another, they are able to accurately estimate the object’s size even when they cannot see it.
• This suggests that our past experience of objects is important in judging the size of an object.

Experiment 2:

Aims:

• To see whether familiarity & size knowledge is used to judge distance.
• To see whether participants were able to judge the distance of familiar objects categorised as token invariant more accurately than familiar objects that were token variable/unfamiliar objects. 

Procedure:

• 9 male university students that did not participate in experiment 1 were screened for normal vision before taking part.
• Participants were taken to a large, open field with trees round 3 of its edges.
• The field was divided into 4 sections, 3 which were in front of the position where the participants were made…