Role of eccentricity and size in the global precedence effect.

Abstract

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...

Local and global auditory processing: Behavioral and ERP evidence

“…It is also interesting to note that the amount of interference of local pitch change direction on global processing was modulated by amount of global pitch change when local change remained constant. The global precedence effects observed in the current study are consistent with visual spatial processing findings that behavioral measures of global precedence are generally seen across a range of stimulus parameters (De Lillo, et al, 2005;Hoffman, 1980;Navon, 1981Navon, , 1991 and that these effects can be reduced by increasing the difficulty of the global perception task (Amirkhiabani & Lovegrove, 1996; Antes & Mann, 1894).…”

“…It is also interesting to note that the amount of interference of local pitch change direction on global processing was modulated by amount of global pitch change when local change remained constant. The global precedence effects observed in the current study are consistent with visual spatial processing findings that behavioral measures of global precedence are generally seen across a range of stimulus parameters (De Lillo, et al, 2005;Hoffman, 1980;Navon, 1981Navon, , 1991 and that these effects can be reduced by increasing the difficulty of the global perception task (Amirkhiabani & Lovegrove, 1996; Antes & Mann, 1894).Asymmetric interference effects were evident in evoked responses even under conditions in which congruency effects on accuracy were similar at the local and global levels. Superficially, the timing of local-on-global interference effects as indexed by ERPs for visual hierarchical figures (Han & Chen, 1996;Han et al, 1999;Han et al, 2000a;Johannes et al, 1996) and auditory stimuli is very similar.…”

Subordinate-level categorization relies on high spatial frequencies to a greater degree than basic-level categorization

“…Although a simple, fixed, coarse-to-fine analysis of visual information does not seem adequate to explain all the data available (Amirkhiabani & Lovegrove, 1996;Greaney & MacRae, 1992;Kim, Ivry, & Robertson, 1999;Lamb & Robertson, 1989, 1990Lamb & Yund, 2000;Schyns, 1998;Shedden & Reid, 2001; see Kimchi, 1992, for a review of earlier work), a general advantage of low spatial frequencies and global shapes remains well supported. In general, larger, global, low spatial frequency elements are processed preferentially relative to small, local, high spatial frequency elements (Kimchi, 1992), especially when the different levels are equated for conspicuity (Love et al, 1999).…”

Do the global advantage and interference effects covary?

“…In other words, according to this view, the influence of variations in eccentricity is negligible, in comparison with attentional factors. According to the second interpretation, however, visual acuity decreases with an increase in eccentricity (Amirkhiabani & Lovegrove, 1996). The decrease in acuity may be interpreted as being the result of a decrease in the density of cone receptors at the peripherallocations (Cornsweet, 1970).…”

“…However, it is not the purpose of the present study to investigate the source of these effects or to test whether the global advantage and interference effects reflect the order of processing. Readers interested in these matters may refer to Amirkhiabani and Lovegrove (1996). What we want to examine in the present study is whether, in a well-controlled experimental condition, the two effects, regardless of their origins, covary.…”