The effect of spatial frequency on global precedence and hemispheric differences

Abstract

There are many conditions in which identification proceeds faster for the global form of a hierarchical pattern than for its local parts. Since the global form usually contains more lower spatial frequencies than do the local forms, it has frequently been suggested that the higher transmission rate of low spatial frequencies is responsible for the global advantage. There are also functional hemispheric differences. Whilethe right hemisphere is better at processing global information, the left hemisphere has an advantage with respect to local information. In accordance with the spatial-frequency hypothesis, it has been speculated that this difference is due to a differential capacity of the hemispheres for processing low and high spatial frequencies. Totest whether low spatial frequencies were responsible for the global advantage and/or for the observed hemispheric differences, two experiments were carried out with unfiltered and highpass-filtered compound-letter stimuli presented at the left, right, or center visual field. The first experiment, in which the target level was randomized in each trial block, revealed that low spatial frequencies were not necessary for either global advantage or for hemispheric differences. Highpass filtering merely increased the response times. In the second experiment, the target level was held constant in each block. This generally increased the speed of responding and produced interactions between filtering and global-local processing. It was concluded that both sensory and attentional or control mechanisms were responsible for global precedence and that the hemispheres differed with respect to the latter.Since the pioneering paper of Navon (1977; also see Kinchla, 1974), the time course of the processing ofhierarchical stimuli has been extensively investigated. Navon used so-called compound letters, which are global letter forms constructed from identical smaller local letters (see Figure 1). Usually, it is easy to focus one's attention on either the local or the global level. Interestingly, Navon found that the identification of the global form proceeded faster than that of the local letters. Moreover, if the information at the global and local levels was conflicting, then global information interfered with local processing, but not vice versa. 1will denote a response time advantage for the processing of global forms together with an interference asymmetry as global advantage. To account for the global advantage observed in his data, Navon formulated the global-precedence hypothesis, which states that the information is processed serially at both levels and that the global information is processed first.Meanwhile, it has been demonstrated that the global response time advantage varies over a wide range and can even become negative (e.g., .

On attentional control as a source of residual shift costs: Evidence from two-component task shifts.

“…With respect to levels, responses to the global level are usually faster than those to the local level, and the interference from global to local is larger than vice versa (cf. Hübner, 1997;Navon, 1977). Similarly, less-greater judgments are usually faster than odd-even judgments, and there is a corresponding interference asymmetry (e.g., Allport et.…”

“…As mentioned, shift costs were often unaffected by dominance relations (e.g. Hübner, 1997;Hübner & Backer, 1999;Sudevan & Taylor, 1987) or affected in a contraintuitive way (cf. Allport et al, 1994, Experiment 4).…”

“…For instance, cross talk usually increases in conditions with randomized components relative to constant ones (e.g. Hübner, 1997Hübner, , 2000. To examine whether this also held for the present case, we included constant conditions in the next experiment and compared the corresponding consistency effects and shift costs with those in randomized conditions.…”

“…It is known that shifts between the levels of such hierarchical stimuli produce costs (e.g. Hübner, 1997Hübner, , 2000Robertson, 1996;Ward, 1982). Thus, in our experiments the participants had to extract a numeral from the prespecified level and classify it according to the required task.…”

Local–global interference is modulated by age, sex and anterior corpus callosum size

“…However, reaction time (RT) studies show diverging evidence for visual field effects supporting lateralized global/local processing (Blanca et al, 1994;Evert and Kmen, 2003;Hübner, 1997;Yovel et al, 2001; for meta-analysis see Van Kleeck, 1989), whereas nearly all published electrophysiological studies using compound letters in event-related designs report hemispheric asymmetries in the expected direction (Heinze and Münte, 1993;Heinze et al, 1998;Malinowski et al, 2002;Yamaguchi et al, 2000). In an event-related potential (ERP) study with both central and lateralized stimulus presentations Han and colleagues (2002) found hemispheric differences only for centrally presented stimuli.…”