Abstract
The aim of this article is to review studies on human anxiety using the startle reflex
methodology and to apply the literature on context conditioning in rats to interpret
the results. A distinction is made between cued fear (as in specific phobia), a phasic
response to an explicit threat cue, and anxiety, a more sustained and future-oriented
response not linked to a specific discrete cue. Experimentally, contextual fear, as
opposed to cued fear, may best reflect the feeling of aversive expectation about potential
future dangers that characterizes anxiety. Following a brief description of the neurobiology
of cued fear and context conditioning, evidence is presented showing that anxious
patients are overly sensitive to threatening contexts. It is then argued that the
degree to which contextual fear is prompted by threat depends on whether the danger
is predictable or unpredictable. Consistent with animal data, unpredictable shocks
in humans result in greater context conditioning compared to predictable shocks. Because
conditioning promotes predictability, it is proposed to use conditioning procedures
to study the development of appropriate and inappropriate aversive expectations. Cued
fear learning is seen as an adaptive process by which undifferentiated fear becomes
cue-specific. Deficits in cued fear learning lead to the development of nonadaptive
aversive expectancies and an attentional bias toward generalized threat. Lacking a
cue for threat, the organism cannot identify periods of danger and safety and remains
in a chronic state of anxiety. Factors that may affect conditioning are discussed.
Keywords
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Article info
Publication history
Accepted:
August 30,
2002
Received in revised form:
August 9,
2002
Received:
April 3,
2002
Identification
Copyright
© 2002 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
