A. Öhman and J.J.F. Soares (1994) demonstrated
that masked presentation of phobic pictures produces increased
skin conductance responses (SCRs) in phobic subjects. A.
Öhman (1993) explained this phenomenon in terms of
a hypothetical “feature detector” that identifies
physical characteristics of stimuli and activates the arousal
system without involving significance evaluation or consciousness.
By exposing spider phobics to spider words, general threat
words, and neutral words instead of pictures, this explanation
was tested. Words were presented both masked and unmasked
while electrodermal activity was measured. Under unmasked
conditions, SCRs were largest for spider words followed
by general threat words, then neutral words. When masked,
the difference between spider words and general threat
words disappeared but SCRs remained significantly smaller
for neutral words. It is concluded that activation of the
arousal system by masked threat cues does not necessarily
depend on their perceptual characteristics.