Harrison Henry S, Kelty-Stephen Damian G, Vaz Daniela V, Michaels Claire F
Center for the Ecological Study of Perception and Action, Department of Psychology, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, Connecticut 06269-1020, USA.
Center for the Ecological Study of Perception and Action, Department of Psychology, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, Connecticut 06269-1020, USA and Department of Psychology, Grinnell College, 1116 8th Avenue, Grinnell, Iowa 50112, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jun;89(6):060903. doi: 10.1103/PhysRevE.89.060903. Epub 2014 Jun 17.
Pole balancing is a key task for probing the prospective control that organisms must engage in for purposeful action. The temporal structure of pole-balancing behaviors will reflect the on-line operation of control mechanisms needed to maintain an upright posture. In this study, signatures of multifractality are sought and found in time series of the vertical angle of a pole balanced on the fingertip. Comparisons to surrogate time series reveal multiplicative-cascade dynamics and interactivity across scales. In addition, simulations of a pole-balancing model generating on-off intermittency [J. L. Cabrera and J. G. Milton, Phys. Rev. Lett. 89, 158702 (2002)] were analyzed. Evidence of multifractality is also evident in simulations, though comparing simulated and participant series reveals a significantly greater contribution of cross-scale interactivity for the latter. These findings suggest that multiplicative-cascade dynamics are an extension of on-off intermittency and play a role in prospective coordination.
杆平衡是探究生物体为有目的行动而必须进行的前瞻性控制的关键任务。杆平衡行为的时间结构将反映维持直立姿势所需控制机制的在线运作。在本研究中，在指尖平衡杆的垂直角度的时间序列中寻找并发现了多重分形特征。与替代时间序列的比较揭示了跨尺度的乘性级联动力学和交互性。此外，还分析了一个产生开关间歇性的杆平衡模型的模拟结果[J. L. 卡布雷拉和J. G. 米尔顿，《物理评论快报》89, 158702 (2002)]。多重分形的证据在模拟中也很明显，不过比较模拟序列和参与者序列发现，后者的跨尺度交互性贡献明显更大。这些发现表明，乘性级联动力学是开关间歇性的扩展，并在前瞻性协调中发挥作用。
