Walking changes the dynamics of cognitive estimates of time intervals.

Abstract

Cognitive performance exhibits patterns of trial-to-trial variation that can be described as 1/f or pink noise, as do repeated measures of locomotor performance. Although cognitive and locomotor performances are known to interact when performed concurrently, it is not known whether concurrent performance affects the tasks' pink noise dynamical structure. In this study, participants performed a cognitive task (repeatedly producing a temporal interval) and a motor task (walking on a treadmill) in single- and dual-task conditions. In single-task conditions both tasks exhibited pink noise structure. For concurrent performance the dynamical structure of the cognitive task changed reliably in the direction of white (random) noise. The dynamical structure of locomotion remained pink noise. The change in cognitive dynamics occurred despite no reliable changes in mean or standard deviation measures for either task. The results suggest a functional reorganization of cognitive dynamics supporting successful task performance in dual-task conditions.

Fractal fluctuations in gaze speed visual search

“…4 describes RMS around a regressed line. Fractal time series generally exhibit scaling exponents H in the range .5 < H ≤ 1, with stronger fractality yielding an H closer to 1 (e.g., Kiefer, Riley, Shockley, Villard, & Van Orden, 2009). Logarithmic scaling of Eq.…”

Dynamics of cognition

“…[135][136][137][138] Dynamical systems inspires alternative conceptions of dual-task performance as a higher-order, synergistic coordination that spans the two tasks and in the process induces reparameterization 139 of motor performance. 71,[140][141][142][143] For certain tasks, this perspective yields precise, quantitative predictions about the effects of cognitive performance on the noisiness and stability of motor performance. These alternative conceptions are motivated further by a number of apparent violations of the dictum that dualtasking results in degraded performance-for example findings that postural stability is improved when a standing person engages in a concurrent mental task.…”

“…32 Dualtask (motor + cognitive) performance can also affect 1/f scaling. Kiefer et al 71 had participants walk on a treadmill or perform repeated temporal estimations, or perform both tasks concurrently. When performed separately, each task yielded clear 1/f scaling, but in the dual-task condition the variations in cognitive performance became essentially random (although the mean and amount of variability of the temporal estimates did not change compared to the singletask condition).…”

“…Standard tools used to asses the structure of variability were applied to perceptual-motor behaviors such as finger tapping, [63][64][65][66] eye movements, 67 and locomotion. [68][69][70][71] Warren 72 developed a general modeling framework for behavioral dynamics, articulated in terms of the emergence of behavioral trajectories from informational and forceful (mechanical) animalenvironment and perception-action couplings in the context of behavioral goals (modeled as attractors) and obstacles (modeled as repellers). The literature on dynamical systems in perception-action is vast, and reviews of this body of research can be found elsewhere.…”

Voluntary performance

“…In more difficult or less familiar tasks, the variation in the data can depart from the pink noise complexity, sometimes toward a random pattern of white noise with a flat spectral slope and a scaling exponent α=0 (e.g., [25][26][27][28][29][30]. Difficulty and novelty may, in this instance, be two ways (among others) of injecting unsystematic change into human performance, from one trial to the next.…”