Whole-Body Multifractal Synergies Support Cognitive Visual Word Search

Michael T. Turvey viewed perceptual facility with words as a nonlinear prestress of whole-body synergies, forming a multifractal tensegrity rather than a computational cognitive mechanism. This reanalysis of young adults completing an upright-postural Stroop-like conjunction search links three aspects of multifractal synergies to the cognitive processes involved in the visual word search. First, searching tightly constrained task space benefits from reducing multifractal postural variability. Visual search for incongruently colored words occurred with less multifractal nonlinearity in the postural center of pressure (CoP), particularly for targets within a narrow visual angle. Second, physical constraint or destabilization requires compensatory changes in multifractal variability elsewhere. Restraining stance led successful search to become associated with increased multifractal nonlinearity in movement fluctuations at the head and clavicle. Third, applying task constraints that narrow search in the visual field links search performance with multifractal variability higher up in the body, i.e. closer to the narrowed search. Searching for inverse-incongruent words (e.g. a red-colored “blue” instead of a blue-colored “red”) benefited from the reduction of multifractal nonlinearity in clavicle rather than in CoP displacement. Multi-joint synergies of multifractal nonlinear interactions support visual-word search by responding to or imposing constraints and reorganizing in response to intentional shifts.