title: 7-year (circaseptennian) patterns in psychology and biology? Comment on Verhulst and Onghena.
abstract: 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.
authors.affiliation: University of Minnesota, Minneapolis 55455, USA.
authors.forename: G
authors.initials: G
authors.lastname: Cornélissen
authors.forename: R B
authors.initials: RB
authors.lastname: Sothern
authors.forename: F
authors.initials: F
authors.lastname: Halberg
authors.forename: F
authors.initials: F
authors.lastname: Halberg
mesh_terms: D000818:Animals; D001695:Biology / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D006801:Humans; D016018:Least-Squares Analysis; D008962:Models, Theoretical; D010507:Periodicity; D011584:Psychology / Q000706:statistics & numerical data