SOURCES STATEMENT I certify that the thesis entitled The Role o f Eccentricity and Size in the Global PrecedenceEffect, and submitted for the degree of Doctor of Philosophy, is the result of my own research, except where otherwise acknowledged, and that this thesis (or any part of the same) has not been submitted for a higher degree to any other university or institution. Navon (1977) purposed that global configurations are processed more quickly than are local components. Kinchla and Wolfe (1979) demonstrated that this global precedence was lost when the global stimuli exceeded 6-9 degrees of visual angle. Navon and Norman (1983) noted that Kinchla and Wolfe confounded size and eccentricity. They attempted to unconfound these two variables and concluded that global precedence was found with both large and small stimuli when eccentricity was not a confound.It is argued that the controversy in the global precedence hypothesis has partially resulted from the fact that the concepts of the global and local and the attributed relationship between these two vary in different experiments and among workers. In the present study a new approach to global-local relationships was introduced. Global-local relationships were classified into four groups: Inclusion, placeholder, dimensional, and featural relationships. Any of these relationships may or may not be accompanied by a semantic relationship between the global and local levels. The Stroop-type interference of the global and local levels refers to some sort of conventional semantic relationship between the levels. Based on an extensive study of the literature it was suggested that the perception of the global and local levels of a compound pattern is dependent on the type of relationship between two levels. The presented study was limited to test the effect of size and eccentricity of the compound pattern on the processing of the global and local levels with inclusion and placeholder relationships.Debate is still very active regarding the global precedence effect. The present study questioned the initial logic behind this hypothesis about the equal recognisability of the global and local levels, an axiom which has been accepted without being tested. This was investigated in a series of experiments by considering the effects of eccentricity and size and their possible interaction on the processing of the two structural levels, using compound patterns of placeholder and inclusion relationships. Furthermore, the possible iii effect of size/eccentricity uncertainty on the temporal order of processing of the global and local levels and patterns of response times were examined across eccentricity. The results showed a global advantage regardless of attentional strategies or experimental presentation conditions when the eccentricity was controlled. The study of Stroop-type interference between the global and local levels indicated a discontinuity in global/local interference with variations in size and eccentricity. It seems that size and eccentricity are the main determina...

The global precedence hypothesis has been operationally defmed as a faster or earlier processing of the global than of the local properties of an image (global advantage) and as interference by processing at the global level with processing at the local level (global interference). Navon (1977) proposed an association between the global advantage and interference effects. Other studies have shown a dissociation between the two effects (e.g., Lamb & Robertson, 1988).It seems that the controversy in previous research resulted from not equalizing the eccentricities of global and local properties. In the present study, the eccentricities of the two levels were equalized by using stimuli with all their elements located along their perimeters. The results of the first experiment demonstrated that although the global level was identified faster than the local level in both the central and the peripheral locations of the visual field (global advantage), the pattern of global interference varied across the visual field. Consistency of global and local levels increased the speed of processing of the local level displayed at the center of the visual field but slowed down the processing of that level at peripheral locations. The results of Experiment 2 demonstrated that it was most likely that the variation in the pattern of global interference was determined by the variable of eccentricity, rather than by the sizes of the global and local levels.The so-called global precedence hypothesis has been studied with at least two major performance measures: the relative speed of identification and asymmetric interference. The asymmetric interference reported in the global precedence studies usually refers to a Stroop-type effect in which processing of local properties is affected by processing at the global level much more than the latter is affected by the former. There has been a controversy in the literature, however, over the association between the global/local advantage and interference effects and over its universality.For example, Kinchla and Wolfe (1979) suggested that the temporal order of processing is not always from global to local. Rather, it varies according to the size of the compound pattern. To be able to study the effect of the size of the stimulus on processing at global and local levels, they chose to have five different sizes of stimuli, from 4.8°to 22.1°. They mixed stimuli of these different sizes together in one block and randomly presented them to the subject. This meant that the subject was uncertain about the size and eccentricity of the incoming stimuCorrespondence concerning this article should be addressed to G. Amirkhiabani, Faculty of Arts, Health and Science, Central Queensland University, Rockhampton, QLD, 4702, Australia (e-mail: a.keen@ cqu.edu.au). -Accepted by previous editor, Myron L. BraunsteinIus.' The results of Kinchla and Wolfe's study indicated that the global level was detected faster when its size was less than 6°_9°and slower when its size was over that limit.Navon and Norman (1983)...

Absolute and relative sizes of global and local visual stimuli have been suggested as the prime determinants of the so-called global precedence effect; however, in none of these studies has the relative size of the two levels been manipulated. Difference in size seems to be the most distinct aspect of differentiating global and local levels of a visual stimulus. In this study the effect of variations in relative size of global and local levels on the global-local advantage and interference effects was examined. Analysis showed that, when the stimulus was displayed at a peripheral location, relative size was probably the prime determinant of global advantage and interference. In addition, both global and local information was processed faster when the stimulus was projected to the left visual field than to the right one. This finding was more compatible with the hypothesis of verbal-visuospatial hemispheric specialisation than with a part-whole dichotomy.

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The term ‘cognitive strategies’ is problematic and needs clarification. Although it has been used in various studies in psychology and education, there is little agreement as to what is meant by ‘cognitive strategy.’ There is no clear-cut differentiation in the literature between ‘cognitive strategies,’ ‘metacognition,’ ‘skills,’ ‘schemas,’ ‘tasks,’ and other related concepts. Some researchers assume that people know and are aware or conscious of what strategies they are using, while others emphasize involuntary and unconscious aspects of strategies. In this article, paradigms which are involved in studies of cognitive strategies are considered. Because use of this concept is problematic and vague, the study of cognition is less focused than is desirable, and important problems in the field are overlooked.