The present study used the picture perception paradigm
to examine the extent to which three well-documented psychophysiological
measures demonstrate consistency across time in response
to emotional stimuli. The three measures were the eye-blink
startle response and the activation in two facial muscle
regions (zygomatic and corrugator). Twenty-seven young
women were assessed on two occasions, 2 weeks apart. Whereas
activation in the corrugator and zygomatic muscle regions
demonstrated the predicted patterns at both assessments
(with some attenuation in the zygomatic muscle regions),
the startle response had limited consistency across the
two assessments. The startle response revealed the predicted
linear pattern of valence modulation during the first assessment.
During the second assessment, startle magnitude response
was a quadratic function of valence ratings and a linear
function of arousal ratings. The unexpected pattern of
startle response during the second session appeared to
be related to the content of the pleasant slides, with
action slides generating quadratic valence modulation and
erotic slides continuing to exhibit the expected linear
valence modulation.