Object-related attention
There are three different theories about the selection of visual attention . These would be object-based or object-based attention , location -based or space-based attention , and dimension-based attention .
The theory of location-based attention compares attention with a cone of light (spotlight). Stimuli in the "illuminated" locations are processed faster and more thoroughly than stimuli in other locations. The dimension-based attention, on the other hand, is not directed to an abstract location in the visual field, but has to select between different stimulus attributes, i.e. between different dimensions of attributes.
The theory of object-related attention, which will be explained in more detail below through Duncan's experiments, states that attention can only be directed to one object at a time. If one looks at the object in its spatial extent, it can be interpreted as "in the spotlight", whereby location and object-based attention do not exclude each other. The connection between object-based and dimension-based attention is illustrated by the experiments of Müller and O'Grady (2000).
Duncan's experiments
Duncan's experiments provided evidence for the existence of object-based attention for the first time.
John Duncan conducted several tests on subjects in 1984. By turning off both dimensional and space-based attention by limiting the viewing angle to less than 1 ° and controlling the number of dimensions of an object, he was able to investigate the influence of object-based attention. He assumed that attention can only be focused on one object at a time and that seeing is thus limited to one object at a time. The preliminary consideration for the experiment was that test subjects should describe two aspects of a briefly presented visual field. Performance should depend on whether the aspects to be described relate to one or two objects. Assessing two aspects of just one object should be as easy as judging just one aspect of an object. However, it should be more difficult to name two aspects of two objects, since only one object would be perceptible at a time.
Test procedure
For these experiments, he showed the test subjects two different objects. This was a vertically oriented rectangle, the size of which had to be assessed and had a small gap either in the right or in the left side. The other object was a line running through the rectangle, either dotted or dashed, sloping clockwise or counter-clockwise, so each of the two objects had two independent attributes. Only two of these attributes were relevant for each test subject and only these varied. There were different experimental arrangements. The test person either had to assess one attribute of an object, two attributes of an object, or two attributes of both objects varied.
Results
If only one object was taken into account, the performance for the judgment on one attribute was very similar as for double judgments on two attributes. So there was no impairment of performance in the second judgment. However, when two objects were observed, there was a drop in performance in two judgments, but this was limited to the second judgment. There may have been competition for attention, with data showing that the item whose property was to be assessed first was favored because performance fell on the second assessment.
The results of the experiments cannot be explained with the location- or dimension-based attention, since Duncan controlled aspects of the location- and dimension-based attention theories during the experiments (<1 ° viewing angle, dimension of attributes), so that Duncan with these experiments evidence for object-based perception and Attention.
Further research
Later experiments on the subject of attention (Müller, HJ, O'Grady, RB, 2000) dealt with another aspect of attention: the dimension-based approach. Above all, this should clarify the relationship between the individual theories of selective visual attention. The result of the investigation was evidence of the existence of both dimensional and object-based attention. However, no dependency between these could be determined. Dimensional and object-related attention seem to work simultaneously and independently of one another.
literature
- John Duncan: Selective attention and the organization of visual information. In: Journal of Experimental Psychology / General. Volume 114, 1984, pp. 501-517.
- Hermann J. Müller, Rebecca B. O'Grady: Dimension-based visual attention modulates dualjudgment accuracy in Duncan's (1984) one- versus two-object report paradigm. In: Journal of Experimental Psychology / Human Perception and Performance. Volume 26, 2000, pp. 1332-1351.
- Jochen Müsseler (Ed.): General Psychology. Spectrum, Berlin 2008, ISBN 978-3-8274-1780-0 .