Those interested in the relationships between psychological and
physiological functions will again and again be impressed by the fact
that great individual differences and large situational variability are
manifested in psychophysiological data. Psychophysiology from a
differential perspective has been an enduring theme throughout the
history of personality and temperament research. However, the present
book is the first to bear the word differential in its title. Actually,
this monography is not only concerned with psychophysiological
personality research, but with a much broader program of systematic
investigation. Multivariate research methodology permits one to
operationalize physiological response profiles, both with regard to
lasting differences between persons and the discrimination of
situations. In order to determine functional relationships between
person characteristics and situational demands, that is, to determine
the processes of stimulus-response mediation, one first needs to
systemize these various sources of variance in assessment models and
subsequently partition the observed covariance. A series of the author's
own investigations in the Hamburg and Freiburg laboratories shows just
how fruitful this research approach can be.