Abstract
The extent to which spatial frequency (SF) is used to guide attention in hierarchical (Navon) displays is disputed, but ample evidence suggests that global perception may involve low spatial frequency (LSF) processing and that local perception may involve high spatial frequency (HSF) processing (Shulman et al., 1986; Shulman & Wilson, 1987; Robertson, 1996). It is debated whether SF selection is a low-level mechanism associating global and local information with absolute LSF and HSF content, or whether it is a higher level mechanism involving a selective process that defines the SF range in which global and local can then be relatively defined. We provided evidence supporting the latter claim in an earlier study (Flevaris et al., 2008) where we demonstrated that selection of LSFs or HSFs in a compound grating was influenced by the hierarchical level (global or local) attended. In the present study we extended our previous findings by demonstrating that attention to hierarchical level influenced SF selectivity despite a change in retinal location of the hierarchical stimuli and the grating stimulus. Participants viewed pairs of peripheral Navon displays and were asked to make same/different judgments on the global or local levels in separate blocks. Following the hierarchical displays, a single compound SF grating appeared at fixation and participants made orientation judgments about either the “thick lines” (LSFs) or the “thin lines” (HSFs). Importantly, the same compound SF gratings were presented in each block and what differed across blocks was the particular SF that was task relevant. Despite the change in task and retinal location between the Navon displays and the SF gratings, participants were faster at selecting lower than higher SFs following attention to the global level of the Navon displays, and they were faster at selecting higher than lower SFs following attention to the local level.