7-Year (circaseptennian) patterns in psychology and biology? Comment on Verhulst and Onghena

Germaine Cornélissen, Robert B. Sothern, Francine Halberg, Franz Halberg

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Nonlinear rhythmometry confirms a pattern of about 7 years, describing the number of births by birth year of quantum fathers reported by Verhulst and Onghena in 1996 and estimates the period to be 6.53 years with a 95% confidence interval overlapping 7 years. Other patterns of about 7 years are found in biology, as shown herein for the mean gonadal weight of an echinoderm (the purple sea urchin) and a mollusk (the black chiton). A number of periodic components with different frequencies, some shown to be genetically anchored, await applications in psychology as well as in other fields of medicine and biology.

Original languageEnglish (US)
Pages (from-to)483-487
Number of pages5
JournalPsychological reports
Issue number2
StatePublished - Apr 1998


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