Helena M. Purkis

No support for dual process accounts of human affective learning in simple Pavlovian conditioning.

Dual process accounts of affective learning state that the learning of likes and dislikes reflects a learning mechanism that is distinct from the one reflected in expectancy learning, the learning of signal relationships, and has different empirical characteristics. Affective learning, for example, is said not to be affected by: (a) extinction training; (b) occasion setting; (c) cue competition; and (d) awareness of the CS‐US contingencies. These predictions were tested in a series of experiments that employed simple Pavlovian conditioning procedures. Neutral visual pictures of geometric shapes, or tactile conditional stimuli (CS) were paired with aversive electrotactile unconditional stimuli (US). Dependent measures were physiological (skin conductance, blink startle modulation) or verbal (US expectancy, on‐line and off‐line ratings of CS pleasantness). Different combinations of these dependent measures were employed across different experiments in an attempt to assess affective and expectancy learning simultaneously. Changes in CS pleasantness as indexed by ratings or blink startle modulation were readily observed. However, contrary to the predictions from dual‐process accounts, results indicated that acquired CS unpleasantness is subject to extinction, occasion setting, cue competition, and not found in absence of CS‐US contingency awareness.

The origins of specific phobias: Influential theories and current perspectives

Fears are quick and adaptive responses that permit powerful reply to imminent threats. Less adaptive, phobias are extreme manifestations of fear to objects or situations in the absence of a proportional danger. Although the utility of fear is accepted, the nature of phobias is controversial. Initial theories favored a fear conditioning-based explanation, with vicarious and information learning pathways subsequently included as additional routes to the development of specific phobias. More recently, an important group of investigations strengthened the case for a nonassociative account of fear acquisition proposing that evolutionarily relevant fears can occur without any need of critical learning experiences. In parallel, there is some evidence for a dedicated fear module in the detection of threats, involving the amygdala, which is relatively independent from conscious cognitive control. Nonetheless, cognitive models stress learning and developmental factors and their role in the etiology and maintenance of phobic behavior. This article critically reviews each of these views and theories stressing their recent developments, weaknesses, and controversies with an aim to provide the groundwork for the construction of a more integrated position. Finally, the authors suggest encouraging trends in recent research.

Automatic attention does not equal automatic fear: preferential attention without implicit valence.

Theories of nonassociative fear acquisition hold that humans have an innate predisposition for some fears, such as fear of snakes and spiders. This predisposition may be mediated by an evolved fear module (Ohman & Mineka, 2001) that responds to basic perceptual features of threat stimuli by directing attention preferentially and generating an automatic fear response. Visual search and affective priming tasks were used to examine attentional processing and implicit evaluation of snake and spider pictures in participants with different explicit attitudes; controls (n = 25) and snake and spider experts (n = 23). Attentional processing and explicit evaluation were found to diverge; snakes and spiders were preferentially attended to by all participants; however, they were negative only for controls. Implicit evaluations of dangerous and nondangerous snakes and spiders, which have similar perceptual features, differed for expert participants, but not for controls. The authors suggest that although snakes and spiders are preferentially attended to, negative evaluations are not automatically elicited during this processing.

But what about the Empress of Racnoss? The allocation of attention to spiders and Doctor Who in a visual search task is predicted by fear and expertise

If there is a spider in the room, then the spider phobic in your group is most likely to point it out to you. This phenomenon is believed to arise because our attentional systems are hardwired to attend to threat in our environment, and, to a spider phobic, spiders are threatening. However, an alternative explanation is simply that attention is quickly drawn to the stimulus of most personal relevance in the environment. Our research examined whether positive stimuli with no biological or evolutionary relevance could be allocated preferential attention. We compared attention to pictures of spiders with pictures from the TV program Doctor Who, for people who varied in both their love of Doctor Who and their fear of spiders. We found a double dissociation: interference from spider and Doctor-Who-related images in a visual search task was predicted by spider fear and Doctor Who expertise, respectively. As such, allocation of attention reflected the personal relevance of the images rather than their threat content. The attentional system believed to have a causal role in anxiety disorders is therefore likely to be a general system that responds not to threat but to stimulus relevance; hence, nonevolutionary images, such as those from Doctor Who, captured attention as quickly as fear-relevant spider images. Where this leaves the Empress of Racnoss, we are unsure.

Are snakes and spiders special? Acquisition of negative valence and modified attentional processing by non-fear-relevant animal stimuli

Previous research has demonstrated differences in processing between fear-relevant stimuli, such as snakes and spiders, and non-fear-relevant stimuli. The current research examined whether non-fear-relevant animal stimuli, such as dogs, birds and fish, were processed like fear-relevant stimuli following aversive learning. Pictures of a priori fear-relevant animals, snakes and spiders, were evaluated as negative in affective priming and ratings and were preferentially attended to in a visual search task. Pictures of dogs, birds and fish that had been trained as CS+ in an aversive conditioning design were evaluated more negatively and facilitated dot probe detection relative to CS− pictures. The current studies demonstrated that stimuli viewed as positive prior to aversive learning were negative and were preferentially attended to after a brief learning episode. We propose that aversive learning may provide a mechanism for the acquisition of stimulus fear relevance.

Reaction time facilitation by acoustic task-irrelevant stimuli is not related to startle.

Previous research has been interpreted to suggest that the startle reflex mediates the RT facilitation observed if intense, accessory acoustic stimuli are presented coinciding with the onset of a visual imperative stimulus in a forewarned simple RT task. The present research replicated this finding as well as the facilitation of startle observed during the imperative stimulus. It failed, however, to find any relationship between the size of the blink startle reflex elicited by the accessory acoustic stimuli, which differed in intensity and rise time, and RT or RT facilitation observed on trials with accessory acoustic stimuli. This finding suggests that the RT facilitation is not mediated by the startle reflex elicited by the accessory acoustic stimuli.

Better safe than sorry: Simplistic fear-relevant stimuli capture attention

It has been consistently demonstrated that fear-relevant images capture attention preferentially over fear-irrelevant images. Current theory suggests that this faster processing could be mediated by an evolved module that allows certain stimulus features to attract attention automatically, prior to the detailed processing of the image. The present research investigated whether simplified images of fear-relevant stimuli would produce interference with target detection in a visual search task. In Experiment 1, silhouettes and degraded silhouettes of fear-relevant animals produced more interference than did the fear-irrelevant images. Experiment 2, compared the effects of fear-relevant and fear-irrelevant distracters and confirmed that the interference produced by fear-relevant distracters was not an effect of novelty. Experiment 3 suggested that fear-relevant stimuli produced interference regardless of whether participants were instructed as to the content of the images. The three experiments indicate that even very simplistic images of fear-relevant animals can divert attention.

Specific phobias in older adults: characteristics and differential diagnosis

BACKGROUND Differential diagnosis implies identifying shared and divergent characteristics between clinical states. Clinical work with older adults demands not only the knowledge of nosological features associated with differential diagnosis, but also recognition of idiosyncratic factors associated with this population. Several factors can interfere with an accurate diagnosis of specific phobia in older cohorts. The goal of this paper is to review criteria for specific phobia and its differential diagnosis with panic disorder, agoraphobia, post-traumatic stress disorder and obsessive compulsive disorder, while stressing the specific factors associated with aging. METHODS A literature search regarding specific phobia in older adults was carried out using PubMed. Relevant articles were selected and scanned for further pertinent references. In addition, relevant references related to differential diagnosis and assessment were used. RESULTS Etiologic factors, specificity of feared stimulus or situation, fear predictability and the nature of phobic situations are key points to be assessed when implementing a differential diagnosis of specific phobia. CONCLUSIONS First, age-related sensory impairments are common and interfere both with information processing and communication. Second, medical illnesses create symptoms that might cause, interfere with, or mimic anxiety. Third, cohort effects might result in underreporting, through the inability to communicate or recognize anxiety symptoms, misattributing them to physical conditions. Finally, diagnostic criteria and screening instruments were usually developed using younger samples and are therefore not adapted to the functional and behavioral characteristics of older samples.

Modality-specific attentional startle modulation during continuous performance tasks: A brief time is sufficient

Attentional startle modulation has been found to be modality specific in continuous performance tasks (CPTs) and modality nonspecific in trial-structured tasks. Experiment 1 investigated whether attentional blink modulation in a CPT would change if a trial structure was imposed. Participants performed a visual CPT either continuously (CONT), or during brief periods of time signaled by a change in screen color with stimuli either presented all the time (MIXED) or only during the trial segments (DISC). Contrary to expectation, evidence for modality-specific attentional startle modulation-smaller acoustic startle during targets than during nontargets-was strongest in Groups MIXED and DISC. Experiment 2 confirmed that this pattern of results was present during the first stimulus of the task period in group DISC. This suggests that the continuous nature of a task is not critical in determining the attentional mechanisms engaged.

The effect of startle reflex habituation on cardiac defense: interference between two protective reflexes.

The present study investigated the relationship between blink startle and cardiac defense, two protective reflexes that are said to be elicited by the transient and the sustained components, respectively, of high intensity stimuli. Three groups of participants were presented with three intense long lasting noise stimuli (500ms) after habituation training with 12 brief (50ms) high intensity noise bursts (High group), low intensity noise bursts (Low group) or high intensity visual stimuli (Light group). The transition from habituation to defense stimuli resulted in increased blink startles in groups Low and Light, but not in group High. A cardiac defense reflex, characterised by a short and long delayed increase in heart rate, was observed in group Light, but not in groups Low and High. This pattern of results indicates that habituation to startle eliciting stimuli will impair defense reflexes elicited on subsequent test trials and suggests some interrelation between the two reflex systems.