Abstract
Fear overgeneralization and perceived uncertainty about future outcomes
have been suggested as risk factors for clinical anxiety. However,
little is known regarding how they influence each other. In this study,
we investigated whether different levels of threat uncertainty influence
fear generalization. Three groups of healthy participants underwent a
differential fear conditioning protocol followed by a generalization
test. All groups learned to associate one female face (conditioned
stimulus, CS+) with a female scream (unconditioned stimulus, US) while
the other face (CS-) was not associated with the scream. In order to
manipulate threat uncertainty, one group (low uncertainty, n =
26) received 80%, the second group (moderate uncertainty, n =
32) received 60%, and the third group (high uncertainty, n = 30)
40% CS-US contingency. In the generalization test, all groups saw CS+
and CS- again as well as four morphs that varied in similarity with the
CS+ in steps of 20%. Subjective (expectancy, valence, and arousal
ratings), psychophysiological (skin conductance response, SCR), and
visuocortical (steady-state visual evoked potentials, ssVEPs) indices of
fear were registered. Participants expected the US in accordance with
their reinforcement schedules but displayed stronger skin conductance
with more uncertainty. However, acquisition of conditioned fear was not
evident in ssVEPs. During the generalization test, we found no effect of
threat uncertainty in any of the measured variables, but the strength of
generalization for threat expectancy ratings was positively correlated
with dispositional intolerance of uncertainty. This study suggests that
mere threat uncertainty does not modulate fear generalization.
Keywords: fear generalization, threat uncertainty, skin
conductance, steady-state visual evoked potentials, intolerance of
uncertainty