Biomedical subjects

Peter F Lovibond

Publications and source records attributed to Peter F Lovibond.

12 recordsLinked to original sources

PubMed2006

Extinction in human fear conditioning.

Although most extinction research is conducted in animal laboratories, the study of extinction learning in human fear conditioning has gained increasing attention over the last decade. The most important findings from human fear extinction are reviewed in this article. Specifically, we review experimental investigations of the impact of conditioned inhibitors, conditioned exciters, context renewal, and reinstatement on fear extinction in human samples. We discuss data from laboratory studies of the extinction of aversively conditioned stimuli, as well as results from experimental clinical work with fearful or anxious individuals. We present directions for future research, in particular the need for further investigation of differences between animal and human conditioning outcomes, and research examining the role of both automatic and higher-order cognitive processes in human conditioning and extinction.

Animals↗

PubMed2006

Forward blocking in human learning sometimes reflects the failure to encode a cue-outcome relationship.

In two "allergist" causal judgement experiments, participants were trained with a blocking design (A+|AB+). The procedure allowed different food cues to be paired with different fictitious allergic reactions. On test, participants were asked to rate the causal efficacy of the target cues and to recall the particular allergic reaction (outcome) that had followed each cue during training. Forward blocking was observed on the causal judgement measure and on the outcome recall measure in both Experiment 1 and Experiment 2. A backward blocking contingency was also trained in Experiment 2 (AB+|A+). Backward blocking was not observed either on the causal judgement or on the outcome recall measure. The evidence from the recall measure suggests that forward blocking in this task results from a failure to encode the B-outcome relationship during training. Associative and nonassociative mechanisms of forward blocking are discussed.

Association↗

PubMed2005

Inference-based retrospective revaluation in human causal judgments requires knowledge of within-compound relationships.

In an allergist causal-judgment task, food compounds were followed by an allergic reaction (e.g., AB+), and then 1 cue (A) was revalued. Experiment 1, in which participants who were instructed that whatever was true about one element of a causal compound was also true of the other, showed a reverse of the standard retrospective revaluation effect. That is, ratings of B were higher when A was causal (A+) than when A was safe (A-). This effect was taken to reflect inferential reasoning, not an associative mechanism. In Experiment 2, within-compound associations were found to be necessary to produce this inference-based revaluation. Therefore, evidence that within-compound associations are necessary for retrospective revaluation is consistent with the inferential account of causal judgments.

Allergens↗

PubMed2005

A dissociation between causal judgment and outcome recall.

It has been suggested that causal learning in humans is similar to Pavlovian conditioning in animals. According to this view, judgments of cause reflect the degree to which an association exists between the cause and the effect. Inferential accounts, by contrast, suggest that causal judgments are reasoning based rather than associative in nature. We used a direct measure of associative strength, identification of the outcome with which a cause was paired (cued recall), to see whether associative strength translated directly into causal ratings. Causal compounds AB+ and CD+ were intermixed withA+ and C- training. Cued-recall performance was better for cue B than for cue D; thus, associative strength was inherited by cue B from the strongly associated cue A (augmentation). However, the reverse was observed on the causal judgment measure: Cue B was judged to be less causal than D (cue competition). These results support an inferential over an associative account of causal judgments.

Association↗

PubMed2004

Probability and cost estimates for social and physical outcomes in social phobia and panic disorder.

Individuals with Social Phobia (SP) (n = 23) and Panic Disorder (n = 22), and a non-anxious comparison (NAC) group (n = 62) rated the probability and cost of negative outcomes in the physical and the social domains. Overall, participants rated physical events as less probable but more costly than social events. Compared to the non-anxious group, participants with Social Phobia made significantly higher probability and cost estimates for social events, but not for physical events. Multiple regression analyses demonstrated that perceived cost of negative social events was the strongest unique predictor of scores on the Fear of Negative Evaluation Scale (FNE). Participants with Panic Disorder made significantly higher probability and cost estimates for both physical and social outcomes, compared to non-anxious participants. Both physical probability and social cost estimates predicted scores on the Body Sensations Questionnaire (BSQ). Findings support the disorder-specificity of cognitive biases in Social Phobia, but suggest that individuals with Panic Disorder have a wider range of judgment biases than previously thought.

Adult↗

PubMed2004

The cognitive content of thought-listed worry episodes in clinic-referred anxious and nonreferred children.

We investigated the cognitive content of worry in 8- to 13-year-old clinic-referred anxious (n = 38) and nonreferred (n = 51) children. The children were interviewed individually. They thought-listed their latest worry episodes, rated the uncontrollability of the episodes, and reported on the strategies they used to terminate worry. Content analyses showed that children's worry episodes contained predominantly thoughts reflecting negative outcome anticipation, but other types of thought content also were present. These included problem-solving, ruminating, and self-blaming thoughts. Compared to clinic-referred children, nonreferred children reported more problem solving and less ruminating. In the nonreferred group, increasing age was associated with more problem solving and less ruminating. No such age-related associations were found in the clinic-referred group. The 2 groups did not differ in the types of worry-termination strategies they reported, but clinic-referred children were more likely to keep worrying until the perceived threat was removed. The results suggest that the problem-solving function of worry is still emerging during late childhood and that developmental delays in problem solving may be associated with excessive and uncontrollable worrying.

Adolescent↗

PubMed2003

Causal beliefs and conditioned responses: retrospective revaluation induced by experience and by instruction.

The author tested causal beliefs and conditioned responses in a task involving retrospective revaluation of the causal status of a target cue with respect to electric shock. Successful revaluation was observed on both self-report shock expectancy and skin conductance, whether the training trials were directly experienced, described, or partly experienced and partly described. The results contradict models that link anticipatory conditioned responses to a separate or earlier process from that underlying explicit causal knowledge. They suggest instead that a single learning process gives rise to propositional knowledge that (a) drives anticipatory responding, (b) forms the basis for self-reported causal beliefs, and (c) can be combined with other knowledge, provided either by experience or symbolically, to generate inferences such as retrospective revaluation.

Association Learning↗

PubMed2002

Backward and forward blocking in human electrodermal conditioning: blocking requires an assumption of outcome additivity.

Blocking was observed in two human Pavlovian conditioning studies in which colour cues signalled shock. Both forward (Experiment 1) and backward (Experiment 2) blocking was demonstrated, but only when prior verbal and written instructions suggested that if two signals of shock (A+ and B+) were presented together, a double shock would result (AB++). In this case, participants could assume that the outcome magnitude was additive. Participants given non-additivity instructions (A+ and B+ combined would result in the same outcome, a single shock) failed to show blocking. Modifications required for associative models of learning, and normative statistical accounts of causal induction, to account for the impact of additivity instructions on the blocking effect, are discussed. It is argued that the blocking shown in the present experiments resulted from the operation, not of an error-correction learning rule, nor of a simple contingency detection mechanism, but of a more complex inferential process based on propositional knowledge. Consistent with the present data, blocking is a logical outcome of an A+/AB+ design only if participants can assume that outcomes will be additive.

Acoustic Stimulation↗

PubMed2002

The role of awareness in Pavlovian conditioning: empirical evidence and theoretical implications.

This article reviews research over the past decade concerning the relationship between Pavlovian conditioning and conscious awareness. The review covers autonomic conditioning, conditioning with subliminal stimuli, eyeblink conditioning, conditioning in amnesia, evaluative conditioning, and conditioning under anesthesia. The bulk of the evidence is consistent with the position that awareness is necessary but not sufficient for conditioned performance, although studies suggestive of conditioning without awareness are identified as worthy of further investigation. Many studies have used inadequate measures of awareness, and strategies for increasing validity and sensitivity are discussed. It is concluded that conditioning may depend on the operation of a propositional system associated with consciousness rather than a separate, lower level system.

Awareness↗

PubMed2002

Autonomic and eyeblink conditioning are closely related to contingency awareness: reply to Wiens and Ohman (2002) and Manns et al. (2002).

S. Wiens and A. Ohman (2002) disputed the conclusion that Pavlovian conditioning is strongly related to contingency awareness (P. F. Lovibond & D. R. Shanks, 2002) on the basis that an inappropriate definition of awareness was used. J. R. Manns, R. E. Clark, and L. R. Squire (2002) contended that delay eyeblink conditioning is independent of awareness. The authors of the present article consider these arguments, highlight several problems in the new studies described by the commentators, and conclude that there is still little evidence for unconscious conditioning in either subliminal autonomic conditioning or eyeblink conditioning. The most parsimonious account of existing data is that a single learning process gives rise to both awareness and conditioned responding. Further progress in evaluating the possibility of unconscious conditioning would be facilitated by the development of more completely specified and testable dual-process models.

Autonomic Nervous System↗

PubMedDate not supplied

The utility of somatic items in the assessment of depression in patients with chronic pain: a comparison of the Zung Self-Rating Depression Scale and the Depression Anxiety Stress Scales in chronic pain and clinical and community samples.

OBJECTIVE: To investigate the role of somatic items in the assessment of depression in chronic pain. METHODS: The Self-Rating Depression Scale was administered to 398 individuals with chronic pain, 313 psychology clinic patients with similar overall levels of depression, and a general population sample of 491. All three samples were also administered the Depression Anxiety Stress Scales. RESULTS: Confirmatory factor analysis of pooled Self-Rating Depression Scale and Depression Anxiety Stress Scales items revealed that Self-Rating Depression Scale items denoting diurnal variation, decreased appetite, weight loss and constipation failed to contribute to depression in all 3 samples. Items denoting tachycardia and irritability also failed to discriminate between depression and a combined anxiety/stress factor in all 3 samples. The chronic pain sample endorsed somatic items, in particular psychomotor retardation, sleep disturbance, constipation, and fatigue, more strongly than the other samples relative to their endorsement of nonsomatic depression items. CONCLUSIONS: It was concluded that depression measures that give emphasis to somatic symptoms provide poor measures of depression severity in any individuals and in patients with chronic pain may lead to an overestimation of the severity of depression. More recently developed instruments avoid these limitations and are also better able to discriminate depression from related states such as anxiety and tension/stress.

Adult↗

PubMedDate not supplied

Cognitive processes in extinction.

Human conditioning research shows that learning is closely related to consciously available contingency knowledge, requires attentional resources, and is influenced by language. This research suggests a cognitive model in which extinction consists of changes in contingency beliefs in long-term memory. Laboratory and clinical evidence on extinction is briefly reviewed, and it is concluded that the evidence supports the cognitive position. There is little evidence for a separate, noncognitive conditioning system. The primary implication for neural analysis is that learning and extinction are unlikely to be reducible to direct connections in which one stimulus simply activates or inhibits the memory representation of another. Rather, an adequate neural model will involve the integration of both low-level and high-level systems, including attention, representation of stimulus relations in long-term memory, and a dynamic performance mechanism based on anticipation, not just activation.

Animals↗