Bending rules: the shape of the perceptual generalisation gradient is sensitive to inference rules.

Generalising what is learned about one stimulus to other but perceptually related stimuli is a basic behavioural phenomenon. We evaluated whether a rule learning mechanism may serve to explain such generalisation. To this end, we assessed whether inference rules communicated through verbal instructions affect generalisation. Expectancy ratings, but not valence ratings, proved sensitive to this manipulation. In addition to revealing a role for inference rules in generalisation, our study has clinical implications as well. More specifically, we argue that targeting inference rules might prove to be an effective strategy to affect the excessive generalisation that is often observed in psychopathology.

Generalization of pain-related avoidance behavior based on de novo categorical knowledge.

ABSTRACT: People with chronic pain often fear and avoid movements and activities that were never paired with pain. Safe movements may be avoided if they share some semantic relationship with an actual pain-associated movement. This study investigated whether pain-associated operant responses (movements) can become categorically associated with perceptually dissimilar responses, thus motivating avoidance of new classes of safe movements-a phenomenon known as category-based avoidance generalization. Using a robotic arm, 2 groups were trained to categorize arm movements in different ways. Subsequently, the groups learned through operant conditioning that an arm movement from one of the categories was paired with a high probability of pain, whereas the others were paired with either a medium probability of pain or no pain (acquisition phase). Self-reported pain-related fear and pain expectancy were collected as indices of fear learning. During a final generalization test phase, the movements categorically related to those from the acquisition phase were made available but in the absence of pain. Results showed that the generalization of outcome measures depended on the categorical connections between arm movements, ie, the groups avoided and feared the novel generalization movement categorically related to the pain-associated acquisition movement, depending on how they had previously learned to categorize the movements. This suggests that operant pain-related avoidance can generalize to safe behaviors, which are not perceptually, but categorically, similar to a pain-associated behavior. This form of pain-related avoidance generalization is problematic because category-based relations can be extremely wide reaching and idiosyncratic. Thus, category-based generalization of operant pain-related avoidance merits further investigation.

The Concept of Contexts in Pain: Generalization of Contextual Pain-Related Fear Within a de Novo Category of Unique Contexts.

The experience of unpredictable pain fluctuations can trigger anticipatory pain-related fear. When discrete predictors for pain are lacking, fear typically accrues to the broader environmental context: a phenomenon referred to as contextual pain-related fear. We examined whether conceptual similarity between discrete contexts facilitates pain-related fear generalization; this mechanism is known as category-level fear generalization. Using a voluntary joystick movement paradigm, pain-free participants performed movements in 2 contexts (within-subjects design); context was manipulated by varying background color screens. In the predictable context, one movement predicted pain and another did not. In the unpredictable context, 2 other movements never predicted pain but pain was unpredictably delivered during the context. Participants subsequently learned to categorize novel background colors (ie, generalization contexts) as being similar to either the unpredictable or predictable pain context. Then we tested fear generalization to these novel contexts. We measured self-reported pain-related fear, expectancy, and eyeblink startle. Results indicated higher pain-related fear reports, but no elevated startle responses, for generalization contexts that were trained to be similar to the original unpredictable context rather than the predictable pain context. This highlights a potential pathway through which neutral contexts can elicit pain-related fear and motivate avoidance behavior associated with chronic pain disability. PERSPECTIVE: Self-reported pain-related fear and expectancy of painful outcome in response to a context associated with unpredictable pain generalizes to perceptually distinct contexts that are trained to be conceptually similar to the unpredictable pain context. Category-level generalization may be a pathway contributing to spreading of fear and avoidance in chronic pain.

One for all: The effect of extinction stimulus typicality on return of fear.

BACKGROUND AND OBJECTIVES: During exposure therapy, patients are encouraged to approach the feared stimulus, so they can experience that this stimulus is not followed by the anticipated aversive outcome. However, patients might treat the absence of the aversive outcome as an 'exception to the rule'. This could hamper the generalization of fear reduction when the patient is confronted with similar stimuli not used in therapy. We examined the effect of providing information about the typicality of the extinction stimulus on the generalization of extinction to a new but similar stimulus. METHODS: In a differential fear conditioning procedure, an animal-like figure was paired with a brief electric shock to the wrist. In a subsequent extinction phase, a different but perceptually similar animal-like figure was presented without the shock. Before testing the generalization of extinction with a third animal-like figure, participants were either instructed that the extinction stimulus was a typical or an atypical member of the animal family. RESULTS: The typicality instruction effectively impacted the generalization of extinction; the third animal-like figure elicited lower shock expectancies in the typical relative to the atypical group. LIMITATIONS: Skin conductance data mirrored these results, but did not reach significance. CONCLUSION: These findings suggest that verbal information about stimulus typicality can be a promising adjunctive to standard exposure treatments.