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The aim of this study was to further investigate whether the interpretation of an ambiguous stimulus is influenced by immediate past experience, and, therefore, by the establishment of a perceptual set. It is based on an experiment conducted by Bugelski and Alampay (1961).

It was hypothesized that interpretation of an ambiguous stimuli that can be perceived as either a rat or a human face will be influenced by the context under which they view the figure and their past experience with other figures. That is they will be influenced by their perceptual set.

The results from this study supported the hypothesis with the results showing that 88.9% of the participants shown animals perceived the ambiguous figure to be an animal. In group B 80% of participants shown faces perceived the ambiguous figure to be a face.

In conclusion perceptual set, past experience and context play a major role in how humans perceive what they see in day to day life and have a huge influence on what we think we see.

Is it a rat or is it a man?

How accurate is human perception? How confident should courts be in using eye witness testimony? Is it possible that people really only see what they want, or expect to see?

Human beings take their perception for granted; in fact most would agree they have little choice. This however does not mean that human perception is always accurate. Psychological factors can have a profound influence on how humans interpret in coming sensory stimuli.

A perceptual set is the inclination to recognize stimuli in accordance with certain expectations that often cause us to select certain aspects of the visual stimuli to be organized and interpreted, yet to ignore other aspects, and because of this perceptual set is often referred to as expectancy.

The influence of context on visual perception was demonstrated in an experiment by American psychologists Jerome Bruner and Leigh Minturn (1955). In this experiment, one group of participants were assigned the roles of observers (group A) and shown pictures of letters and group B were shown pictures of numbers they were then both shown an ambiguous figure. They then had to identify the last symbol (ambiguous figure) and draw it. The group A who had been shown letters perceived the figure to be the letter B, 92% of the time were as Group B who had been shown numbers perceived the symbol to be 13, 83% of the time. It showed that a perceptual set or expectancy had been established by the time the 'ambiguous figure was to be interpreted.

Past experience refers to personal experiences that have occurred through ones life. These experiences are skewed, in that a given response may be interpreted in a very personal way by different people. It is also apparent that context and past experience work together in their influence on humans’ interpretation of a visual stimulus. To the point to which we familiarize with the context often depends on our past experiences.

The current study aims to further investigate whether the interpretation of an ambiguous stimulus is influenced by immediate past experience, and, therefore, by the establishment of a perceptual set. It is based on an experiment conducted by Bugelski and Alampay (1961).

It is hypothesized that participants interpretation of the ambiguous stimuli that can be perceived as either a rat or a human face will be influenced by the context under which they view the figure and their past experience with other figures. That is they will be influenced by their perceptual set.

More specifically it is hypothesized that participants who view other images of faces prior to viewing the ambiguous figure will perceive the image as a face, whereas participants who view other images of animals prior to viewing the ambiguous figure will perceive the image as a rat.

The independent variable for this study was the exposure to pictures of faces and animals.

The dependent variable for this study was the perception of ambiguous “rat man”

Method

Participants

Participants for this study were 19 year 12 psychology students from Woodleigh School on the Mornington peninsula. 8 of which were males and 11 were females aged between 16 and 18.

Materials

Four animal pictures, Four human face pictures, An ambiguous figure that could