TY  - JOUR
  - Woodley, M.; te Nijenhuis, J ; Murphy, R.
  - 2014
  - May
  - Intelligence
  - Is there a dysgenic secular trend towards slowing simple reaction time? Responding to a quartet of critical commentaries.
  - Published
  - ()
  - 46
  - 131
  - 147
  - Previously Woodley, te Nijenhuis ; Murphy (2013) [Woodley, M.A., te Nijenhuis, J., ;Murphy, R. (In press)] tested the hypothesis that the Victorians were cleverer thanrelatively more modern populations, using measures of simple visual reaction time in ameta-analytic study. Based on 13 age-matched studies from Western countries conducted between 1884 and 2004 yielding 16 data points we estimated a decline of -13.35 IQ points. Here we respond to a quartet of critical commentaries on our paper [Flynn (in press), Nettelbeck (2013), Silverman (2013), Dodonova ; Dodonov (2013)]. We show via various reanalyses of the data and also via careful consideration of the arguments presented that the original finding of a significant dysgenic effect on g as captured using the secular decline in simple reaction time performance is essentially robust. A recurrent criticism of our finding stems from earlier work showing no secular trends with respect to inspection time over a 20-year period in Australia despite the possibility of dysgenic fertility during this period. We deal with this via the method of correlated vectors, which reveals the presence of a „genetic g‟ common factor on which simple RTs, WAIS gloadings and subtest heritabilities load positively and significantly, but on whichinspection time does not load. This indicates that inspection times are associated withlocal information processing, unlike simple reaction times, which are associated withglobal processing (i.e. g). The robustness of our original finding is best illustratedhowever by the results of our final meta-regression, in which the use of six methodsvariance-controlled reaction time means taken from the US and the UK between 1889and 1993 reveal a dysgenics rate of -.7 of an IQ point per decade, or -8.1 points in total*Manuscript without Title PageClick here to view linked References2between 1889 and 2004. This estimate exhibits virtually zero heterogeneity around themeta-regression line and is furthermore precisely in line with theoretical estimates of therate of dysgenics derived from studies of the IQ/sibling number relationship. Weconclude by arguing that the best way forward is to test novel predictions stemming fromour finding relating to molecular genetics, neurophysiology and social trends, thusshifting the research focus away from the purely methodological level towards thebroader nomological level. We thank the authors for helping us to arrive at a more preciseestimate of the decline in intelligence.
DA  - 2014/05
ER  - 

@article{V239208301,
   = {Woodley, M. and  te Nijenhuis, J  and  Murphy, R.},
   = {2014},
   = {May},
   = {Intelligence},
   = {Is there a dysgenic secular trend towards slowing simple reaction time? Responding to a quartet of critical commentaries.},
   = {Published},
   = {()},
   = {46},
  pages = {131--147},
   = {{Previously Woodley, te Nijenhuis ; Murphy (2013) [Woodley, M.A., te Nijenhuis, J., ;Murphy, R. (In press)] tested the hypothesis that the Victorians were cleverer thanrelatively more modern populations, using measures of simple visual reaction time in ameta-analytic study. Based on 13 age-matched studies from Western countries conducted between 1884 and 2004 yielding 16 data points we estimated a decline of -13.35 IQ points. Here we respond to a quartet of critical commentaries on our paper [Flynn (in press), Nettelbeck (2013), Silverman (2013), Dodonova ; Dodonov (2013)]. We show via various reanalyses of the data and also via careful consideration of the arguments presented that the original finding of a significant dysgenic effect on g as captured using the secular decline in simple reaction time performance is essentially robust. A recurrent criticism of our finding stems from earlier work showing no secular trends with respect to inspection time over a 20-year period in Australia despite the possibility of dysgenic fertility during this period. We deal with this via the method of correlated vectors, which reveals the presence of a „genetic g‟ common factor on which simple RTs, WAIS gloadings and subtest heritabilities load positively and significantly, but on whichinspection time does not load. This indicates that inspection times are associated withlocal information processing, unlike simple reaction times, which are associated withglobal processing (i.e. g). The robustness of our original finding is best illustratedhowever by the results of our final meta-regression, in which the use of six methodsvariance-controlled reaction time means taken from the US and the UK between 1889and 1993 reveal a dysgenics rate of -.7 of an IQ point per decade, or -8.1 points in total*Manuscript without Title PageClick here to view linked References2between 1889 and 2004. This estimate exhibits virtually zero heterogeneity around themeta-regression line and is furthermore precisely in line with theoretical estimates of therate of dysgenics derived from studies of the IQ/sibling number relationship. Weconclude by arguing that the best way forward is to test novel predictions stemming fromour finding relating to molecular genetics, neurophysiology and social trends, thusshifting the research focus away from the purely methodological level towards thebroader nomological level. We thank the authors for helping us to arrive at a more preciseestimate of the decline in intelligence.}},
  source = {IRIS}
}