Impaired Pavlovian conditioned inhibition in offenders with personality disorders

Certain types of violent offending are often accompanied by evidence of personality disorders (PDs), a range of heterogeneous conditions characterized by disinhibited behaviours that are generally described as impulsive. The tasks previously used to show impulsivity deficits experimentally (in borderline personality disorder, BPD) have required participants to inhibit previously rewarded responses. To date, no research has examined the inhibition of responding based on Pavlovian stimulus–stimulus contingencies, formally “conditioned inhibition” (CI), in PDs. The present study used a computer-based task to measure excitatory and inhibitory learning within the same CI procedure in offenders recruited from the “personality disorder” and the “dangerous and severe personality disorder” units of a high-security psychiatric hospital. These offenders showed a striking and statistically significant change in the expression of inhibitory learning in a highly controlled procedure: The contextual information provided by conditioned inhibitors had virtually no effect on their prepotent associations. Moreover, this difference was not obviously attributable to nonspecific cognitive or motivational factors. Impaired CI would reduce the ability to learn to control associative triggers and so could provide an explanation of some types of offending behaviour.     

Making the illusory correlation effect appear and then disappear: The effects of increased learning

The acquisition of a negative evaluation of a fictitious minority social group in spite of the absence of any objective correlation between group membership and negative behaviours was described by Hamilton and Gifford (1976) Hamilton, D. L. and Gifford, R. K. 1976. Illusory correlation in intergroup perception: A cognitive basis of stereotypic judgments. Journal of Experimental Social Psychology, 12: 392–407. [Crossref], [Web of Science ®] , [Google Scholar] as an instance of an illusory correlation. We studied the acquisition and attenuation through time of this correlation learning effect. In two experiments we asked for participants’ judgements of two fictitious groups using an online version of a group membership belief paradigm. We tested how judgements of the two groups changed as a function of the amount of training they received. Results suggest that the perception of the illusory correlation effect is initially absent, emerges with intermediate amounts of absolute experience, but diminishes and is eliminated with increased experience. This illusory correlation effect can be considered to reflect incomplete learning rather than a bias due to information loss in judgements or distinctiveness.     

Want to block earworms from conscious awareness?B(u)y gum!

In a recent article, Jamieson and Mewhort (2009) proposed a novel account of artificial grammar learning (AGL), which is based on a multitrace model of episodic memory, the Minerva 2 model. According to this account, test performance in AGL is based on an assessment of global similarity of the test strings to the memory traces of the training strings. In this article, simulation studies are presented, showing for three different AGL experiments that the predictions of the Minerva 2 model strikingly deviate from participants' performance. It is argued that participants' test performance is not generally based on general similarity.     

Comparing positive and negative patterning in human learning

In human causal learning, positive patterning (PP) and negative patterning (NP) discriminations are often acquired at roughly the same rate, whereas PP is learned faster than NP in most experiments with nonhuman animals. One likely reason for this discrepancy is that most causal learning scenarios encourage participants to treat the presentation and omission of the relevant outcome as two events of comparable significance and likelihood. To investigate this, the current experiments compared PP and NP using a predictive learning paradigm based on a mock gambling task. In Experiment 1, one outcome (winning) was made more salient by being less frequent than the alternative outcome (losing). Under these circumstances, PP was learned faster than NP. In Experiment 2, subjects learned two PP and two NP discriminations, one involved win versus no change outcomes, the other involved lose versus no change outcomes. The subjects learned PP faster than NP, but only when discriminating win from no change. We argue that a difference in difficulty between PP and NP relies on a difference in the salience of the outcomes, consistent with the predictions of a relatively simple model of associative learning.     

Tone of voice guides word learning in informative referential contexts

Listeners infer which object in a visual scene a speaker refers to from the systematic variation of the speaker's tone of voice (ToV). We examined whether ToV also guides word learning. During exposure, participants heard novel adjectives (e.g., “daxen”) spoken with a ToV representing hot, cold, strong, weak, big, or small while viewing picture pairs representing the meaning of the adjective and its antonym (e.g., elephant–ant for big–small). Eye fixations were recorded to monitor referent detection and learning. During test, participants heard the adjectives spoken with a neutral ToV, while selecting referents from familiar and unfamiliar picture pairs. Participants were able to learn the adjectives' meanings, and, even in the absence of informative ToV, generalize them to new referents. A second experiment addressed whether ToV provides sufficient information to infer the adjectival meaning or needs to operate within a referential context providing information about the relevant semantic dimension. Participants who saw printed versions of the novel words during exposure performed at chance during test. ToV, in conjunction with the referential context, thus serves as a cue to word meaning. ToV establishes relations between labels and referents for listeners to exploit in word learning.     

Learning to spell from reading: General knowledge about spelling patterns influences memory for specific words

Adults often learn to spell words during the course of reading for meaning, without intending to do so. We used an incidental learning task in order to study this process. Spellings that contained double n, r and t which are common doublets in French, were learned more readily by French university students than spellings that contained less common but still legal doublets. When recalling or recognizing the latter, the students sometimes made transposition errors, doubling a consonant that often doubles in French rather than the consonant that was originally doubled (e.g., tiddunar recalled as tidunnar). The results, found in three experiments using different nonwords and different types of instructions, show that people use general knowledge about the graphotactic patterns of their writing system together with word-specific knowledge to reconstruct spellings that they learn from reading. These processes contribute to failures and successes in memory for spellings, as in other domains.     

Value learning modulates goal-directed actions

With experience, particular objects can predict good or bad outcomes. This alters our perceptual response to them: Reliable predictors of salient outcomes are recognized faster and better than unreliable predictors, regardless of the value (gain, loss) of the outcome they predict. When attentional resources are constrained, learned value associations matter, causing recognition of gain-associated objects to be spared. Here, we ask how learned predictiveness and value change the way we interact with potentially rewarding objects. After associating virtual objects (drinking flutes) with monetary gains or losses, reaching for and grasping corresponding real objects depended on the object's learned value. Action was faster when directed at objects that previously predicted outcomes more rather than less consistently, regardless of value. Conversely, reaches were more direct for gain- than for loss-associated objects, regardless of their predictiveness. Action monitoring thus reveals how value learning components become accessible during action.     

Modulation of the affordance effect through transfer of learning

Consistent evidence shows that practising with spatially incompatible stimulus–response trials modulates performance on following tasks requiring the solution of cognitive conflict such as the Simon and Stroop tasks. In the present study we assessed whether a spatially incompatible practice can modulate another effect that is thought to be due to a conflict between two response alternatives, the affordance effect. To this end, we requested participants to categorize pictures of common objects on the basis of their upright or inverted orientation. A group of participants performed the categorization task alone, while the other two groups performed the categorization task after practising with a spatial compatibility task with either a compatible or an incompatible mapping. Results showed that the spatially incompatible practice eliminated the affordance effect. These results indicate that the conflict at the basis of the affordance effect is not unavoidable but it rather permeable to modulations affecting the response selection stage. Indeed the “emit the alternative spatial response” rule acquired during the spatially incompatible task can transfer to and modulate how the subsequent affordance task is performed.     

Evidence that a transient but cognitively demanding process underlies forward blocking

Blocking is a learning phenomenon in which prior experience inhibits learning about novel cues. Though the phenomenon itself has been well documented, the details of blocking-related processes still remain contentious. Two experiments investigated whether participants were engaged in demanding cognitive processing during different portions of a standard blocking paradigm. Participants in Experiment 1 engaged in a simple secondary task while completing a standard blocking procedure. Results showed that performance on the secondary task was briefly diminished early in the second phase of the blocking paradigm, when the novel cue is first paired with the pretrained cue. Participants in Experiment 2 performed a difficult cognitive load task during either the early or the late portions of the second phase of blocking. The blocking effect was eliminated when learners were under load early in the second phase, but not when learners were under load late in the second phase. These results suggest that blocking relies on a cognitively demanding process with a distinct time course. Computational simulations illustrate how a model that includes top-down (i.e., cognitively demanding) attentional modulation can reproduce the observed behaviour. This suggests that purely associative processes are not sufficient to explain the observed behaviour. Implications for current accounts of blocking are discussed.     

Overshadowing by fixed- and variable-duration stimuli

Two experiments investigated the effect of the temporal distribution form of a stimulus on its ability to produce an overshadowing effect. The overshadowing stimuli were either of the same duration on every trial, or of a variable duration drawn from an exponential distribution with the same mean duration as that of the fixed stimulus. Both experiments provided evidence that a variable-duration stimulus was less effective than a fixed-duration cue at overshadowing conditioning to a target conditioned stimulus (CS); moreover, this effect was independent of whether the overshadowed CS was fixed or variable. The findings presented here are consistent with the idea that the strength of the association between CS and unconditioned stimulus (US) is, in part, determined by the temporal distribution form of the CS. These results are discussed in terms of time-accumulation and trial-based theories of conditioning and timing.