The Malicious Serpent: Snakes as a prototypical stimulus for an evolved module of fear

As reptiles, snakes may have signified deadly threats in the environment of early mammals. We review findings suggesting that snakes remain special stimuli for humans. Intense snake fear is prevalent in both humans and other primates. Humans and monkeys learn snake fear more easily than fear of most other stimuli through direct or vicarious conditioning. Neither the elicitation nor the conditioning of snake fear in humans requires that snakes be consciously perceived; rather, both processes can occur with masked stimuli. Humans tend to perceive illusory correlations between snakes and aversive stimuli, and their attention is automatically captured by snakes in complex visual displays. Together, these and other findings delineate an evolved fear module in the brain. This module is selectively and automatically activated by once-threatening stimuli, is relatively encapsulated from cognition, and derives from specialized neural circuitry.     

Fears born and bred: toward a more inclusive theory of fear acquisition

Alleged differences between associative and non-associative perspectives are sometimes more apparent than real. The non-associative model describes a pathway to fear that is complementary to associative pathways. It does not seek to usurp conditioning models as applied to evolutionary-neutral fear. We discuss vexing definitional issues surrounding what qualifies as a conditioning event and what characterises the non-associative pathway. Genetic findings are shown to be consistent with the non-associative model of fear. Following discussion of the relation between stress-diathesis models and the non-associative position we conclude by urging a developmental, life-course approach to the understanding of fear acquisition.     

The preparedness theory of phobias and human safety-signal conditioning

Seligman's preparedness theory of phobias implies that fear-relevant stimuli are contraprepared for safety-signal conditioning. This means that it should be very difficult to establish a fear-relevant stimulus as a safety-signal in nonphobic subjects. This hypothesis was tested in an electrodermal conditioning experiment with a picture of a snake serving as the fear-relevant CS and a picture of a flower serving as the fear-irrelevant CS. College students received discrimination training designed to establish the snake and the flower as safety-signals by nonreinforcing each in compound with a fear-eliciting CS. Although both the snake and the flower became conditioned safety-signals, neither stimulus showed greater safety-signal properties than the other. The results are inconsistent with predictions from preparedness theory.     

Instructed fear learning,extinction, and recall: additive effects of cognitive information on emotional learning of fear

The effects of instruction on learning of fear and safety are rarely studied. We aimed to examine the effects of cognitive information and experience on fear learning. Fourty healthy participants, randomly assigned to three groups, went through fear conditioning, extinction learning, and extinction recall with two conditioned stimuli (CS+). Information was presented about the presence or absence of conditioned stimulus–unconditioned stimulus (CS–US) contingency at different stages of the experiment. Information about the CS–US contingency prior to fear conditioning enhanced fear response and reduced extinction recall. Information about the absence of CS–US contingency promoted extinction learning and recall, while omission of this information prior to recall resulted in fear renewal. These findings indicate that contingency information can facilitate fear expression during fear learning, and can facilitate extinction learning and recall. Information seems to function as an element of the larger context in which conditioning occurs.     

Born to fear: non-associative vs associative factors in the etiology of phobias

Poulton and Menzies (Behaviour Research & Therapy 40 (2001) 127-149) review two lines of evidence as supporting a non-associative pathway to the origins of "evolutionary relevant phobias". First, in retrospective studies of mode of onset some recall they have always had this fear. We review here solid evidence that retrospective recall is notoriously unreliable. Second, they note as many nonphobics recall relevant associative learning experiences as do phobics. We argue such studies are very inconclusive because they fail to consider many experiential and personality vulnerability (and invulnerability) factors that strongly impact the outcome of any putative learning experience. Their argument also does not explain the transition from developmental fears to phobias that is central to their thesis. Overall, we call for major methodological improvements in this area, in the context of theoretical developments pointing to interacting vulnerability and invulnerability factors.     

Sex,stress, and fear: Individual differences in conditioned learning

It has long been recognized that humans vary in their conditionability, yet the factors that contribute to individual variation in emotional learning remain to be delineated. The goal of the present study was to investigate the relationship among sex, stress hormones, and fear conditioning in humans. Forty-five healthy adults (22 females) underwent differential delay conditioning, using fear-relevant conditioned stimuli and a shock unconditioned stimulus. Salivary cortisol samples were taken at baseline and after acquisition training and a 24-h-delayed retention test. The results showed that acquisition of conditioning significantly correlated with postacquisition cortisol levels in males, but not in females. This sex-specific relationship was found despite similar overall levels of conditioning, unconditioned responding, and cortisol. There was no effect of postacquisition cortisol on consolidation of fear learning in either sex. These findings have implications for the understanding of individual differences in fear acquisition and risk factors for the development of affective disorders.     

Dental phobias and anxieties: evidence for conditioning processes in the acquisition and modulation of a learned fear

The present study investigated some of the factors which differentiate individuals with dental anxieties and phobias from those without such fears. In particular, two questions were addressed: (i) What differentiates subjects who have never been anxious about dental treatment from subjects who at some time have been anxious? and (ii) What factors lead to subjects changing their attitudes either from anxious to relaxed or from relaxed to anxious? The results suggest that the factors which influence the acquisition and modulation of dental anxieties are consistent with the associative and representational processes portrayed in contemporary models of human conditioning. Subjects who reported never having had anxieties about dental treatment were less likely to have had a painful dental treatment than subjects who did report an anxiety. Subjects who did report a painful dental experience but did not acquire anxiety reported a history of dental treatment favourable to the operation of latent inhibition. Subjects who reported that they were good at enduring pain were more likely to report a longer interval between their very first dental treatment and their first painful dental treatment. Under some conditions in which latent inhibition should have precluded the acquisition of a dental fear, an anxiety appeared to be acquired because a very painful experience had attenuated the latent inhibition process. Subjects whose dental anxiety did not remit reported significantly more painful and traumatic dental experiences than subjects whose anxiety did remit.     

Predicting danger: the nature, consequences, and neural mechanisms of predictive fear learning

The ability to detect and learn about the predictive relations existing between events in the world is essential for adaptive behavior. It allows us to use past events to predict the future and to adjust our behavior accordingly. Pavlovian fear conditioning allows anticipation of sources of danger in the environment. It guides attention away from poorer predictors toward better predictors of danger and elicits defensive behavior appropriate to these threats. This article reviews the differences between learning about predictive relations and learning about contiguous relations in Pavlovian fear conditioning. It then describes behavioral approaches to the study of these differences and to the examination of subtle variations in the nature and consequences of predictive learning. Finally, it reviews recent data from rodent and human studies that have begun to identify the neural mechanisms for direct and indirect predictive fear learning.     

Treatments that weaken Pavlovian conditioned fear and thwart its renewal in rats: implications for treating human phobias

In experiments using a total of 144 albino rat subjects, the authors assessed the ability of fear-weakening treatments to prevent fear renewal (relapse). Conditioned suppression of operant behavior served as the measure of fear in an A-B-A (acquisition-treatment-test) renewal paradigm. In Experiment 1, 100 nonreinforced exposures to a feared cue during treatment (extinction) did not reduce fear renewal relative to 20 exposures. In Experiment 2, explicitly unpaired (EU) treatments thwarted both renewal and reacquisition. In Experiment 3, conditioned inhibition (CI) and differential conditioning (DC) treatments weakened renewal and resisted both reacquisition and a form of reinstatement. In Experiment 4, EU, DC, and CI treatments all thwarted renewal. Evidence suggested that the ability of the treatments to do so reflected the combined effects of transfer of extinction across treatment and test contexts and habituation to the unconditioned stimulus.     

Beyond fear: rapid spatial orienting toward positive emotional stimuli

There is much empirical evidence for modulation of attention by negative -- particularly fear-relevant -- emotional stimuli. This modulation is often explained in terms of a fear module. Appraisal theories of emotion posit a more general mechanism, predicting attention capture by stimuli that are relevant for the needs and goals of the organism, regardless of valence. To examine the brain-activation patterns underlying attentional modulation, we recorded event-related potentials from 20 subjects performing a dot-probe task in which the cues were fear-inducing and nurturance-inducing stimuli (i.e., anger faces and baby faces). Highly similar validity modulation was found for the P1 time-locked to target onset, indicating early attentional capture by both positive and negative emotional stimuli. Topographic segmentation analysis and source localization indicate that the same amplification process is involved whether attention orienting is triggered by negative, fear-relevant stimuli or positive, nurturance-relevant stimuli. These results confirm that biological relevance, and not exclusively fear, produces an automatic spatial orienting toward the location of a stimulus.     

Nuclear Waste: Facts,Fears, and Attitudes1

This study examined the effects of a television documentary about the safety of the Sellafield nuclear reprocessing plant in the Northwest of England upon public attitudes. In a study of 805 respondents from four districts in the Southwest of England, we assessed attitudes and beliefs both before and after the documentary about Sellafield. Results indicated a significant attitude change in a more antinuclear direction. Respondents who had seen or heard about the events at Sellafield tended to be more antinuclear after the broadcast. Finally, respondents living close to the existing nuclear power stations in the Southwest of England tended to see the events at Sellafield as less serious than the remaining respondents. Furthermore, this difference in perceived seriousness between respondents living near a nuclear power station and the remaining respondents was much more pronounced in ratings of the environmental risks of the local nuclear power stations in Southwest England.     

The Origins of Fears of Compassion: Shame and Lack of Safeness Memories,Fears of Compassion and Psychopathology

Empirical and clinical research suggests that some individuals find self-generating compassion and receiving compassion from others difficult and aversive. However, it is unclear how these fears of compassion are linked to early experiences and to psychopathological symptoms. This study explores the relationship between shame traumatic memories, centrality of shame memories, early memories of warmth and safeness, fears of compassion, and depression, anxiety and paranoid symptoms. Participants were 302 individuals from the general community population, who completed self-report measures of fears of compassion, shame memories, early affiliative memories, and psychopathology. Shame traumatic and central memories were positively associated with fears of compassion for self, for others and from others, whereas early memories of warmth and safeness were negatively related to such fears. Path analyses revealed that fears of compassion for self and of receiving compassion from others mediated the effects of shame traumatic memory, centrality of shame memory and early memories of warmth and safeness on depressive, anxious and paranoid symptoms. These findings have implications for therapeutic interventions as these fears, as well as the negative shame-based emotional memories fuelling them, may need to be addressed in therapy to assist patients in self-generating and receiving compassion.     

The tripartite model of fear in children with specific phobias: assessing concordance and discordance using the behavioral approach test

Lang’s tripartite model posits that three main components characterize a fear response: physiological arousal, cognitive (subjective) distress, and behavioral avoidance. These components may occur in tandem with one another (concordance) or they may vary independently (discordance). The behavioral approach test (BAT) has been used to simultaneously examine the three components of the fear response. In the present study, 73 clinic-referred children and adolescents with a specific phobia participated in a phobia-specific BAT. Results revealed an overall pattern of concordance: correlation analyses revealed the three indices were significantly related to one another in the predicted directions. However, considerable variation was noted such that some children were concordant across the response components while others were not. More specifically, based on levels of physiological arousal and subjective distress, two concordant groups (high arousal–high distress, low arousal–low distress) and one discordant (high arousal–low distress or low arousal–high distress) group of youth were identified. These concordant and discordant groups were then compared on the percentage of behavioral steps completed on the BAT. Analyses revealed that the low arousal–low distress group completed a significantly greater percentage of steps than the high arousal–high distress group, and a marginally greater percentage of steps than the discordant group. Potential group differences associated with age, gender, phobia severity, and phobia type were also explored and no significant differences were detected. Implications for theory and treatment are discussed.