Disentangling common and specific neural subprocesses of response inhibition.

Response inhibition is disturbed in several disorders sharing impulse control deficits as a core symptom. Since response inhibition is a cognitively and neurally multifaceted function which has been shown to rely on differing neural subprocesses and neurotransmitter systems, further differentiation to define neurophysiological endophenotypes is essential. Response inhibition may involve at least three separable cognitive subcomponents, i.e. interference inhibition, action withholding, and action cancelation. Here, we introduce a novel paradigm - the Hybrid Response Inhibition task - to disentangle interference inhibition, action withholding and action cancelation and their neural subprocesses within one task setting during functional magnetic resonance imaging (fMRI). To validate the novel task, results were compared to a battery of separate, standard response inhibition tasks independently capturing these subcomponents and subprocesses. Across all subcomponents, mutual activation was present in the right inferior frontal cortex (rIFC), pre-supplementary motor area (pre-SMA) and parietal regions. Interference inhibition revealed stronger activation in pre-motor and parietal regions. Action cancelation resulted in stronger activation in fronto-striatal regions. Our results show that all subcomponents share a common neural network and thus all constitute different subprocesses of response inhibition. Subprocesses, however, differ to the degree of regional involvement: interference inhibition relies more pronouncedly on a fronto-parietal-pre-motor network suggesting its close relation to response selection processes. Action cancelation, in turn, is more strongly associated with the fronto-striatal pathway implicating it as a late subcomponent of response inhibition. The new paradigm reliably captures three putatively subsequent subprocesses of response inhibition and might be a promising tool to differentially assess disturbed neural networks in disorders showing impulse control deficits.

Does sunshine prime loyal? Affective priming in the naming task.

Recent work has found an affective priming effect using the naming task: In pronouncing target words, pronunciation latencies were consistently shorter when the target (e.g., loyal) was preceded by an evaluatively congruent (e.g., sunshine) rather than incongruent prime word (e.g, rain). Using the naming task, no affective priming was found in the present studies irrespective of prime-set size and target-set size (Experiment 1), irrespective of stimulus-onset asynchrony (Experiment 2), and even when a nearly exact replication of previous work that demonstrated the effect was conducted (Experiment 3). Finally, bilingual German/English speakers exhibited strong associative priming, but no affective priming, in both the English as well as the German language (Experiment 4). The results show that priming for evaluatively related words is not a general finding.

Implicit association measurement with the IAT: evidence for effects of executive control processes.

It is argued that a model of goal-independent spreading activation in a social or semantic knowledge structure is insufficient to explain implicit association effects in the IAT (Greenwald, McGhee, & Schwartz, 1998). An alternative account is proposed, which attributes IAT effects to differential costs for switching between task sets. Two experiments were conduced to test this account. In Experiment 1, specific task-set switching cost was a function of IAT condition: switching between tasks was associated with significantly more cost in the incompatible IAT phase. In a second experiment the magnitude of the IAT effect was reduced when task-set reconfiguration was possible in advance of or simultaneously with the upcoming stimulus. The results are discussed with respect to recently suggested accounts of the effect.

Propositional reasoning and working memory: the role of prior training and pragmatic content.

Working memory involvement in propositional reasoning was explored after different kinds of training. The training conditions aimed to reduce the impact of non-analytic heuristics and to enhance analytic inference processes according to mental logic theories, the mental model theory, and the theory of pragmatic reasoning schemata. Following an initial training phase, secondary task interference was investigated using concurrent spatial tapping (Experiment 1), random number generation (Experiment 2), and articulatory suppression (Experiment 3). A training condition practicing the construction and use of mental models via a truth table task increased the disruption of reasoning performance by random number generation and articulatory suppression, whereas the other training conditions did not affect susceptibility to secondary task interference. The results corroborate implications of the mental model theory of reasoning.

On belief bias in syllogistic reasoning.

A multinomial model is used to disentangle the respective contributions of reasoning processes and response bias in conclusion-acceptance data that exhibit belief bias. A model-based meta-analysis of 22 studies reveals that such data are structurally too sparse to allow discrimination of different accounts of belief bias. Four experiments are conducted to obtain richer data, allowing deeper tests through the use of the multinomial model. None of the current accounts of belief bias is consistent with the complex pattern of results. A new theory of belief bias is proposed that assumes that most reasoners construct only one mental model representing the premises as well as the conclusion or, in the case of an unbelievable conclusion, its logical negation. New predictions derived from the theory are confirmed in 4 additional studies.

Training propositional reasoning.

Two experiments compared the effects of four training conditions on propositional reasoning. A syntactic training demonstrated formal derivations, in an abstract semantic training the standard truth-table definitions of logical connectives were explained, and a domain-specific semantic training provided thematic contexts for the premises of the reasoning task. In a control training, an inductive reasoning task was practised. In line with the account by mental models, both kinds of semantic training were significantly more effective than the control and the syntactic training, whereas there were no significant differences between the control and the syntactic training, nor between the two kinds of semantic training. Experiment 2 replicated this pattern of effects using a different set of syntactic and domain-specific training conditions.

An unbiased errors-in-variables approach to detecting unconscious cognition.

Greenwald, Klinger and Schuh (1995) have proposed a regression approach for detecting unconscious cognition. An errors-in-variables approach is presented that corrects for measurement error in the predictor and takes into account that the latent predictor variable is assumed to be non-negative. The new approach requires the same input as the uncorrected regression analysis and provides consistent estimates of regression weights as well as valid statistical tests of their significance. In particular, the method yields a consistent estimate of the regression intercept that provides critical evidence for unconscious cognition. A simulation study illustrates these aspects of the new technique. Several data sets are then reanalysed by means of the new method.

Unraveling social categorization in the "who said what?" paradigm.

A multinomial model of the "Who said what?" paradigm (S. E. Taylor, S. T. Fiske, N. J. Etcoff, & A. J. Ruderman, 1978) explains the pattern of participants' assignment errors by means of the joint operation of several processes. Specifically, memory for discussion statements, person memory, category memory, and 3 different guessing processes can be accommodated by the model. The model's ability to disentangle these processes is validated in a series of 5 experiments. The model thereby enables a more refined use of the "Who said what?" paradigm in testing theories of social categorization. This is demonstrated in a 6th experiment in which the validated model is applied to the study of the effects of cognitive load on categorization.

Correcting for measurement error in detecting unconscious cognition: comment on Draine and Greenwald (1998)

A. G. Greenwald, M. R. Klinger, and E. S. Schuh (1995) have proposed a regression method for detecting unconscious cognition in experiments that obtain measures of indirect and direct effects of stimuli with suspected unconscious effects. Their indirect-on-direct-measure regression approach can produce misleading evidence for indirect effects in the absence of direct effects when the direct-effect measure has typical measurement error. This article describes an errors-in-variables variant of the regression method that corrects for error in the direct-effect measure. Applied to the uses of the regression method by S. C. Draine and A. G. Greenwald (1998) in this issue, the errors-in-variables method affirms substantial evidence for indirect effects in the absence of direct effects.

Interference in immediate spatial memory: shifts of spatial attention or central-executive involvement?

Interference in serial spatial memory was investigated in six experiments. Experiment 1 replicated Experiment 2 by Smyth and Scholey (1994) in showing that listening to tones that originated from different directions interfered with spatial memory. Experiment 2 showed, however, that the effect of mere listening was not observed when this was the only interference condition experienced by the subject. In Experiment 3, a binary pitch discrimination task performed on spatially separated tones impaired recall performance to the same extent as did left-right decisions. The same disrupting effect was also observed when the tones were presented from the same direction in the pitch discrimination task (Experiment 4) as well as in a binary loudness discrimination task (Experiment 5). Finally, repeating heard words did not interfere, whereas pitch discrimination performed on these same words disrupted recall (Experiment 6). It is argued that the disrupting effects reflect not a specifically spatial interference, but a central executive involvement in the rehearsal process in serial spatial memory.

List-context effects in evaluative priming.

Evaluative priming effects are often found in the evaluative decision task, in which persons judge the affective connotation (positive vs. negative) of a target word. The present experiments examined list-context effects to test whether evaluative and semantic priming follow the same laws. In Experiment 1, evaluative priming was found at prime-target stimulus onset asynchronies (SOAs) of 0 ms and 100 ms, but not at SOAs of--100, 200, 600, and 1,200 ms. Experiment 2 manipulated SOA (0, 200, and 1,200 ms) and the proportion (25%, 50%, and 75%) of the prime-target pairs that were evaluatively related. Contrary to the typical finding that increases in the proportion of related prime-target pairs lead to increased priming at long but not short SOAs, an effect of consistency proportion was found at SOAs of 0 ms (for reaction times) and 200 ms (in the accuracy data), but not at the 1,200-ms SOA. The pattern of results is discussed in relation to possible explanatory mechanisms of evaluative priming.

[The proportion affect in affective priming: replication and evaluation of a theoretical explanation]. / Der Anteilseffekt beim affektiven Priming: Replikation und Bewertung einer theoretischen Erklärung.

In the paradigm of the evaluative decision task, K. C. Klauer, C. Rossnagel and J. Musch (1997) have been able to show that in affective priming, contrary to semantic priming, a list context effect occurs already at a short SOA, whereas it does not occur at long SOAs. As a possible explanation of this surprising context effect at a short SOA, a matching mechanism was proposed. The theoretically important consistency proportion effect at an SOA of 0 ms could be replicated in an experiment with 40 participants. The results of a subsequent recognition test, however, suggest that the consistency proportion effect is not mediated by the supposed relatedness-checking mechanism. The Stroop paradigm may provide a better theoretical framework for the explanation of affective priming than the previously assumed analogy to semantic priming.

[Mental images and mental models]. / Mentale Bilder und Mentale Modelle.

Two experiments are conducted to assess the involvement of the visouspatial sketchpad of working memeory in propositional and spatial reasoning, using a dual-task methodology. While a concurrent tracking task was found to interfere with spatial reasoning, no such interference was found with propositional reasoning. The results are discussed with respect to the mental-models theory of reasoning.

Testing the mental model theory of propositional reasoning.

Johnson-Laird, Byrne, and Schaeken (1992) present a theory of propositional reasoning by mental models. The present study provides a comprehensive test of the predictions of that theory for the difficulty of simple disjunctive and conditional inferences. The results are largely consistent with the complex pattern of predictions. They are discussed in the light of recently proposed modifications of the original theory.

[Affect and performance in simple problems]. / Stimmung und Leistungsniveau bei einfachen Aufgaben.

We investigate the effects of emotional mood states on solving simple pattern comparison tasks. It is assumed that the effects of mood are mediated through response biases as well as effort expenditure. Departing from these assumptions, trend hypotheses are derived for the response biases evaluated by means of a signal detection analysis, for the response latencies, and for an adequate index of the underlying ability. The data support the hypotheses, and in particular, a positive mood state is found to improve performance. The assumption of mood-dependent differences in effort expenditure provides a parsimonious and integrative account of our results, while a reduced-capacity view cannot explain the findings obtained under positive mood induction.