Up the garden path: A critique of Penke and Deary and further exploration concerning the Charlton et al. path analysis relating loss of white matter integrity to cognition in normal aging

We reply to criticisms by Penke and Deary (2010) of our model relating loss of white matter integrity in normal aging to cognitive change. We identify difficulties in their alternative path analysis in which they attempt to relate age-related loss of integrity of white matter to changes in general intelligence. We then comment on their general criticisms and their viewpoints concerning use of path analysis.