Nanny Wermuth, Chalmers/Gothenburg University
 
The exciting but slow development of insight: the case of properties
of a factor analysis model



Abstract

About 100 years ago Charles Spearman introduced
factor analysis for the measurement of abilities
of man. A condition he stated to be necessary and
sufficient for his model was shown to be only
necessary by Heywood. But, by using  properties
of M-matrices, introduced 10 years later by Alexander
Ostrowsky, as well as  model equivalence in two classes of
graphical models, studied 50 years later, the Spearman
condition is seen to be necessary and sufficient for
for the types of dependency studied by Spearman,
that is for the relation of  specific task solutions
to a corresponding general ability.