External and internal intentional environments reconsideration of the relationship between sinus arrhythmia and information load

Joseph Shari, Gavriel Salvendy

Research output: Contribution to journalArticle

11 Scopus citations


As part of an investigation aimed at assessing differences in mental workload between machine-paced (MP) and self-paced (SP) work, this study focused on the relative usefulness of sinus arrhythmia (SA) and mean heart rate (MHR) as measures of informational load. Two tasks having contrasting attentional demands were performed both MP and SP by 32 subjects. Physiologically speaking, these tasks were characterized as having either cardiac deceleratory or acceleratory response patterns associated with them. An analysis of non-random trends, motivated by the presence of these response patterns, revealed the standard measure of variance, s2, to be less appropriate than the mean-square successive difference (MSSD) for scoring SA. Utilizing the MSSD, results indicated that MHR was far more sensitive than SA to the differences in informational load resulting from the intrinsic processing demands of these two tasks. SA, on the other hand, was more sensitive to the two pacing conditions. These latter findings, however, were thought to be primarily an artifact of the cardiac response patterns. It was suggested that the effects of attentional mobility on SA were capable of obscuring those of information processing.

Original languageEnglish (US)
Pages (from-to)121-132
Number of pages12
Issue number2
StatePublished - Feb 1982
Externally publishedYes


ASJC Scopus subject areas

  • Human Factors and Ergonomics
  • Physical Therapy, Sports Therapy and Rehabilitation

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