FIRST EXPERIMENTS |
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The first series of experiments looked at the categorisation of everyday objects (e.g., common animals, English letters). Participants were presented with three objects simultaneously and instructed to respond to the middle object. The objects (flankers) on either side of the middle object were always the same as each other and could be presented upright or upside down. The middle object (target) was always upright. In the first experiment, the objects were animals of quite different general shapes (basic structures), i.e., bugs, dogs, and birds. In the second experiment, different participants viewed objects with similar basic structures, i.e., dogs, horses, and cows. Combined the results from these experiments support the idea that the basic structure of objects can be recognised regardless of whether they are upright or upside down. That is, the animals in the first experiment were rapidly distinguishable from each other when upside down (rapidly enough to interfere with responses to the middle object), but the animals in the second experiment were not rapidly distinguishable from each other when upside down. Because the animals in the second experiment share a common basic structure, when inverted they could not be rapidly distinguished from each other.
The second two experiments took the logic of the first two a little further using English letters. Much previous research had already shown that upside down letters can be recognised as quickly as upright letters. So, the first experiment, using Arial font, compared the influence of upright and upside down flanking letters on responses to middle letters. As in the first experiment above, the flankers influenced the responses regardless of whether they were upright or upside down. This supports the idea that these letters could be recognised at any orientation. However, in the second experiment, using Old English font, only the upright letters influenced responses to the middle letter. This meant that in Old English font, only the upright letters could be identified quickly enough to interfere with response to the middle letter.
In summary then, determining the basic shape (basic structure) of an object (e.g., quadruped / dog) may be like determining the identity of a letter. The overall structure of an object can be identified regardless of its orientation, but only when that structure can readily be identified. As long as the brain can determine the basic structure, then it will be rapidly categorised (at least into some category) regardless of its orientation. Therefore, in theory, seeing an “Old English dog” will be hard to recognise as a dog when upside down, and an “Arial dog” will be easy to recognise as a dog when upside down. Variation in font is to letters what breeds of dogs are to the category “dog”; different species of quadrupeds is to the category quadruped what different letters are to the category “letters”. |