A review of contemporary literature revealed that current visuospatial assessment strategies lack available specificity due to the failure to completely isolate parallel from serial processing. Assessment strategies either erroneously make the assumption that by increasing the processing load, parallel processing of the visual field no longer occurs, or they fail to control for variable feature valences on differing dimensions. Using a variation on a widely used letter cancellation task that relied on search symmetry and assymmetry strategies, this study examined if feature and array presentations continue to influence the speed and accuracy of cancellation tasks in a normal population (N=40). A Factorial Design with repeated measures was utilized with the independent variables being target features (either absence or presence of a unitary feature) and the arrays of the cancellation tasks (either linear or non-linear in presentation). Search symmetry and asymmetry strategies did not produce the threshold of discrepancy necessary isolate parallel from serial processing. However, non-linear arrays did demonstrate significantly faster searches than did the linear condition. The outcomes of this study stand in contrast to contemporary understanding of visuospatial functioning. Results are consistent with the existence of two distinct neural pathways as proposed by Mischkin, Ungerleider, and Macko (1983). The need for future research is discussed.
展开▼
