title: Spatiotemporal symmetry and multifractal structure of head movements during dyadic conversation.
abstract: This study examined the influence of sex, social dominance, and context on motion-tracked head movements during dyadic conversations. Windowed cross-correlation analyses found high peak correlation between conversants' head movements over short ( approximately 2-s) intervals and a high degree of nonstationarity. Nonstationarity in head movements was found to be positively related to the number of men in a conversation. Surrogate data analysis offsetting the conversants' time series by a large lag was unable to reject the null hypothesis that the observed high peak correlations were unrelated to short-term coordination between conversants. One way that high peak correlations could be observed when 2 time series are offset by a large time lag is for each time series to exhibit self-similarity over a range of scales. Multifractal analysis found small-scale fluctuations to be persistent, tau(q) < 0.5, and large-scale fluctuations to be antipersistent, tau(q) > 0.5. These results are consistent with a view that symmetry is formed between conversants over short intervals and that this symmetry is broken at longer, irregular intervals.
authors: U.S. Census Bureau, USA.
authors: Kathleen T
authors: KT
authors: Ashenfelter
authors: Steven M
authors: SM
authors: Boker
authors: Jennifer R
authors: JR
authors: Waddell
authors: Nikolay
authors: N
authors: Vitanov
mesh_terms: D005260:Female; D017709:Fractals; D006257:Head; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D015146:Midwestern United States; D008962:Models, Theoretical; D009068:Movement / Q000502:physiology*; D009633:Nonverbal Communication; D012737:Sex Factors; D012930:Social Dominance