Is attentional selection to different levels of hierarchical structure based on spatial frequency?

Target identification is faster when the target level (global or local) is the same as that on the previous trial, presumably because attention is directed to the appropriate level. L. C. Robertson (1996) found that eliminating low spatial frequencies by contrast balancing eliminated this level repetition effect and concluded that attentional selection between different levels of structure is based on spatial frequency. In contrast, M. R. Lamb and E. W. Yund (1996a) found no effect of contrast balancing on the level repetition effect and thus concluded that attentional selection is not based on spatial frequency. In this study, the authors identified the procedural difference between the 2 studies responsible for this difference in results and replicated both findings. The data show that spatial frequency is not a necessary basis for attentional selection between global and local forms. Although it remains possible that spatial frequency is the basis of attentional selection under some circumstances, the data supporting this proposition are not yet compelling.