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Perruchet, Cleeremans, and Destrebecqz (2006) reported a striking dissociation between trends in the conscious expectancy of an event and the speed of a response that is cued by that event. They argued that this indicates the operation of independent processes in human associative learning. However, there remains a strong possibility that this dissociation is not a consequence of associative learning and is instead caused by changes in vigilance or sensitivity based on the recency of events on previous trials. Three experiments tested this possibility with versions of a cued reaction time task in which trends in performance could not be explained by these nonassociative factors. Experiment 1 introduced a dual-response version of the task, in which response-related vigilance should be held relatively constant, and Experiments 2 and 3 used a differential conditioning procedure to separate the influence of recent response cue presentation from the recent associative history of the trial events. In all experiments, similar trends in reaction time were evident, suggesting a genuine influence of associative learning on response performance. Experiment 3 demonstrated that the associative contribution to these trends was not caused by commensurate changes in expectancy of the response cue. (Contains 2 tables and 13 figures.)

Participants in 2 experiments performed 2 simultaneous tasks: one, a dual-target detection task within a rapid sequence of target and distractor letters; the other, a cued reaction time task requiring participants to make a cued left-right response immediately after each letter sequence. Under these rapid visual presentation conditions, it is usually difficult to identify the 2nd target when it is presented in temporal proximity of the 1st target--a phenomenon known as the attentional blink. However, here participants showed an advantage for detecting a target presented during the attentional blink if that target predicted which response cue would appear at the end of the trial. Participants also showed faster reaction times on trials with a predictive target. Both of these effects were independent of conscious knowledge of the target-response contingencies assessed by postexperiment questionnaires. The results suggest that implicit learning of the association between a predictive target and its outcome can automatically facilitate target recognition during the attentional blink and therefore shed new light on the relationship between associative learning and attentional mechanisms. (Contains 2 tables and 6 figures.)

Two groups of rats were trained for 50 days on different discriminations in a magazine approach paradigm. One group was trained with a negative patterning schedule and a positive patterning schedule concurrently: they received intermixed trials of A +, B +, AB-, C-, D-, CD + (A, B, C, and D are four distinct stimuli; the plus sign denotes reinforcement with food, and the minus sign denotes nonreinforcement). The second group of rats was trained with the same four stimuli arranged as compounds and reinforced according to the biconditional schedule AB +, CD +, AC-, and BD-. The first group learned the positive patterning schedule much more quickly than the negative patterning schedule, but they learned the negative patterning schedule more effectively than the second group learned the biconditional schedule. The authors discuss the implications of these findings for models of stimulus representation.

In two experiments, human participants performed a causal judgment task that simultaneously comprised two reciprocal patterning discriminations and a biconditional discrimination. They learned both patterning discriminations more quickly than the biconditional discrimination. Postdiscrimination tests were used to identify participants who had, or had not, learned to apply the patterning rules, as well as participants who continued to expect summation when presented with two cues that predicted the same outcome. All groups were faster to learn the patterning than the biconditional discriminations. These results are inconsistent with models of stimulus representation that invoke configural representations (e.g., Pearce, 1987, 1994; Rescorla & Wagner, 1972) because these models solve biconditional discriminations more readily than patterning discriminations. Keywords: associative learning, rule learning, configural, elemental, negative patterning

Participants initially completed a discrimination task (D1) involving categorization of patterns with multiple common features, each feature being partly predictive of the correct response. In a subsequent target discrimination task (D2), these features were redistributed across new discriminative stimuli. The relative predictiveness of the features in D1 was either maintained in D2 (i.e., features were equally informative in D1 and D2) or switched (i.e., more informative features in D1 were made less informative in D2, and vice versa). Differential performance on D2 suggested that features most predictive of the correct D1 responses became more highly associable than features that were less predictive in Dl. This finding suggests that the associability of individual stimulus elements changes as a consequence of their role in discrimination learning. Keywords: learned associability, discrimination learning, predictive history, elemental representation

The associative view of human causal learning argues that causation is attributed to the extent that the putative cause activates, via an association, a mental representation of the effect. That is, causal learning is a human analogue of animal conditioning. We tested this associative theory using a task in which a fictitious character suffered from two allergic reactions, rash ([O.sub.1]) and headache ([O.sub.2]). In a conditioned inhibition design with each of these two outcomes (A-[O.sub.1]/AX- and B-[O.sub.2]/BY-), participants were trained that one herbal remedy (X) prevented [O.sub.1] and that the other (Y) prevented [O.sub.2]. These inhibitory properties were revealed in a causal judgement summation test. In a subsequent categorization task, X was most easily categorized with [O.sub.1], and Y with [O.sub.2]. Thus, the categorization data indicated an excitatory X-[O.sub.1] and Y-[O.sub.2] association, the reverse of the inhibitory relationship observed on the causal judgement measure. A second experiment showed that this pattern of excitation and inhibition is dependent on intermixed A-[O.sub.1] and AX- trials. These results are problematic for the standard application of associative activation theories to causal judgement. We argue instead that the inhibition revealed in the causal judgement task reflects inferential reasoning, which relies, in part, on the ability of the cue in question to excite a representation of the outcome, as revealed in the categorization test. DOI:10.1080/17470210601002512

Informing participants in a causal judgement task that outcomes are additive call increase blocking effects (Experiment 1). Outcome additivity information emphasizes the fact that the outcome following a compound is the sum of the effects of its elements. We suggest that the effect of providing outcome additivity information is to encourage elemental processing and thereby enhance blocking. Experiment 2 showed that blocking could be enhanced by factors encouraging elemental processing, and Experiment 3 demonstrated that blocking was reduced by manipulating the visual presentation of cues to encourage configural processing. While these experiments do not rule out the role of inference in causal judgement tasks, the results are most parsimoniously explained by associative accounts that allow flexibility in the encoding of compound cues.

Impairments in response inhibition have been implicated in gambling psychopathology. This behavioral impairment may suggest that the neural mechanisms involved in response inhibition, such as GABAA -mediated neurotransmission in the primary motor cortex (M1), are also impaired. The present study obtained paired-pulse transcranial magnetic stimulation markers of GABAA and glutamate receptor activity from the left M1 of three groups-problem gamblers (n = 17, 12 males), at-risk gamblers (n = 29, 19 males), and controls (n = 23, six males)-with each group matched for alcohol use, substance use, and attention-deficit hyperactivity disorder (ADHD) symptomology. Response inhibition was measured using the stop signal task. Results showed that problem gamblers had weaker M1 GABAA receptor activity relative to controls and elevated M1 glutamate receptor activity relative to at-risk gamblers and controls. Although there were no differences in response inhibition between the groups, poorer response inhibition was correlated with weaker M1 GABAA receptor activity. These findings are the first to show that problem gambling is associated with alterations in M1 GABAA and glutamate-mediated neurotransmission. [ABSTRACT FROM AUTHOR]