departmental bulletin paper

Departmental Bulletin Paper

Text

大阪大学大学院人間科学研究科紀要. 2024, 50, p. 131-148

Japanese

Text

2024-03-22

This study revises the interpretation of the Largest Lyapunov Exponent (LLE) in pulse waves, which serves as a crucial metric for analyzing psychological traits and mental states. However, because the LLE originates from chaos theory and measures the intensity of system alterations, it lacks a simple, comprehensible representation in the context of pulse waves. When applied in fields such as psychology, behavioral studies, or everyday life, it necessitates a clear explanation of its significance. Currently, pulse waves are widely understood to signify “inner fl exibility” or “responsiveness to external stimuli.” This interpretation has been widely accepted and applied in numerous studies. However, our subsequent research has found that this definition struggles to explain many observed phenomena. Specifically, we have noticed significant changes in the LLE of pulse waves when subjects are exposed to certain stimuli or engage in specific activities. This is puzzling, because “inner flexibility” or “responsiveness to external stimuli” should not exhibit significant short-term changes. Moreover, the original definition is often perceived as a desirable trait, implying that higher values are preferable. This contradicts the notion that excessively high or unstable LLE values of pulse waves may indicate psychological unhealthiness. Therefore, we have redefined the meaning of the LLE of pulse waves based on various research findings. We now consider the LLE of pulse waves to represent “internal reserves” or “mental energy available to respond to external stimuli.” This revised interpretation aligns more closely with the mathematical significance of LLE and, in conjunction with prior research, clarifies why excessively high values are undesirable. Additionally, this new interpretation can account for phenomena that were challenging to explain under the previous definition. When we apply this new meaning to phenomena that could be explained by both the old and the new definitions, we find that the new interpretation aligns more closely with common sense or general perceptions.

10.18910/94729

94729

脈波測定における最大リアプノフ指数(LLE)の意味に関する再検討

大阪大学大学院人間科学研究科

Japanese

2024-03-22

大阪大学大学院人間科学研究科紀要

50

131

148

https://hdl.handle.net/11094/94729

10.18910/94729

https://doi.org/10.18910/94729