| |
Abstract:
Emotionally arousing visual stimuli have been found to elicit
psychophysiological responses, even in the absence of perception.
We investigated the effects of conscious perception on the skin
conductance response (SCR) to emotional stimuli presented to the
right and left visual hemifield. Forty-one subjects (19 females)
were shown a total of 24 different stimuli (3 stimuli in 8
different stimulus classes). Every stimulus was presented to each
hemisphere in a subliminal condition (backward masking paradigm,
target/mask: 30/2000ms) and a supraliminal condition (target:
2000ms). Datapoints corresponding to outliers (mean±5SD),
failure of fixation, and recognition of stimuli in the subliminal
condition were removed. Overall, results indicated a significantly
higher SCRs in the subliminal condition than in the supraliminal
condition. However, both sub- and supraliminal conditions showed
the same pattern of hemispheric asymmetry: Positive pictures
(babies/animals, food items) produced a larger response when shown
to the left hemisphere; negative and "shocking" pictures
(threatening animals, nudes) and neutral pictures (household
objects, complex social scenes) evoked larger responses when
presented to the right hemisphere. Unexpectedly, pictures of
mutilations always produced a significantly larger response when
presented to the left hemisphere. These data substantiate the
differential processing of emotional stimuli by the left and right
hemispheres, and demonstrate that such differential processing is
engaged even when the stimuli are not perceived consciously.
|
