What must a psychological theory of reasoning explain? Comment on Barrouillet, Gauffroy, and Lecas (2008)

In this comment, it is argued that the modification of mental models theory of conditional inference proposed by P. Barrouillet, C. Gauffroy, and J.-F. Lecas to deal with truth value gaps merely patches up a problem in the theory, rather than accomplishing the fundamental and systematic revision that is necessary. It is argued that P. Barrouillet et al.'s modified mental model theory fails to meet the criteria of good theory of reasoning by invoking an algorithmic-level distinction to resolve a failing in the computational-level theory of the task.     

Hyperformulas and Solid Algebraic Systems

Defining a composition operation on sets of formulas one obtains a many-sorted algebra which satisfies the superassociative law and one more identity. This algebra is called the clone of formulas of the given type. The interpretations of formulas on an algebraic system of the same type form a many-sorted algebra with similar properties. The satisfaction of a formula by an algebraic system defines a Galois connection between classes of algebraic systems of the same type and collections of formulas. Hypersubstitutions are mappings sending pairs of operation symbols to pairs of terms of the corresponding arities and relation symbols to formulas of the same arities. Using hypersubstitutions we define hyperformulas. Satisfaction of a hyperformula by an algebraic system defines a second Galois connection between classes of algebraic systems of the same type and collections of formulas. A class of algebraic systems is said to be solid if every formula which is satisfied is also satisfied as a hyperformula. On the basis of these two Galois connections we construct a conjugate pair of additive closure operators and are able to characterize solid classes of algebraic systems. Presented by Wojciech Buszkowski     

Observing repetitive finger movements modulates response times of auditorily cued finger movements

Our motor and perceptual representations of actions seem to be intimately linked and the human mirror neuron system (MNS) has been proposed as the mediator. In two experiments, we presented biological or non-biological movement stimuli that were either congruent or incongruent to a required response prompted by a tone. When the tone occurred with the onset of the last movement in a series, i.e., it was perceived during the movement presentation, congruent biological stimuli resulted in faster reaction times than congruent non-biological stimuli. The opposite was observed for incongruent stimuli. When the tone was presented after visual movement stimulation, however, no such interaction was present. This implies that biological movement stimuli only affect motor behaviour during visual processing but not thereafter. These data suggest that the MNS is an "online" system; longstanding repetitive visual stimulation (Experiment 1) has no benefit in comparison to only one or two repetitions (Experiment 2).     

The ultimate sampling dilemma in experience-based decision making

Computer simulations and 2 experiments demonstrate the ultimate sampling dilemma, which constitutes a serious obstacle to inductive inferences in a probabilistic world. Participants were asked to take the role of a manager who is to make purchasing decisions based on positive versus negative feedback about 3 providers in 2 different product domains. When information sampling (from a computerized database) was over, they had to make inferences about actual differences in the database from which the sample was drawn (e.g., about the actual superiority of different providers, or about the most likely origins of negatively valenced products). The ultimate sampling dilemma consists in a forced choice between 2 search strategies that both have their advantages and their drawbacks: natural sampling and deliberate sampling of information relevant to the inference task. Both strategies leave the sample unbiased for specific inferences but create errors or biases for other inferences.     

Time course and efficiency of protein synthesis inhibition following intracerebral and systemic anisomycin treatment

Since its discovery in the 1960s, anisomycin has been used for studying the impact of protein synthesis for manifold cerebral processes such as long-term plastic changes after learning. The common limitation of nearly all pharmacological experiments, including anisomycin treatment, is to precisely verify the affected brain regions. Here we illustrate anisomycin effects on protein synthesis in distinct brain regions of mice (C57BL/6JOlaHsd), revealing differences between three modes of anisomycin application (subcutaneous, s.c.; intraperitoneal, i.p.; local microinfusions into the hippocampus). Our method is based on inhibition of the incorporation of the radioactively-labelled amino acids [(35)S]-Methionine/Cysteine into newly synthesised proteins. Washing the brain slices before autoradiography removes pools of amino acids, which have not been incorporated into newly synthesised proteins, thus, illustrating pure protein synthesis. By comparing different routes of systemic anisomycin application (i.p. versus s.c.; 150 mg/kg) it became evident that the effect of i.p. injection of anisomycin is fully reversed after 6 h, whereas s.c. injection is inhibiting protein synthesis in the hippocampus even 9 h after application. Local microinfusions of anisomycin into the hippocampus were shown to have long-lasting effects as well, which reversed as late as 9 h after injection. The diffusion of anisomycin was maximal at 3 h after injection and more precisely confined to the intended area using a lower dose (20 microg/site) instead of the commonly used dose of 62.5 microg/site. The broad time window of anisomycin action, as revealed in our study, has to be considered, if it comes to the interpretation of time course studies within the context of protein synthesis-dependent processes.     

Metacognitive myopia and the overutilization of misleading advice

Previous research on advice taking has explained the failure to exploit collective wisdom in terms of the egocentric underweighting of advice provided by independent others. The present research is concerned with an opposite and more radical source of irrational advice taking, namely, the failure to critically assess the validity of advice due to metacognitive myopia. Participants could use the advice of one or two experts when estimating health risks. They read sketches of the study samples that experts had drawn to estimate conditional probabilities (e.g., of HIV‐given drug addiction). Whether samples were valid or seriously biased, subsequent judgments were strongly affected by any advice (Experiment 1). Uncritical reliance on any advice persisted when participants were sensitized to the contrast of valid and invalid advice in a repeated measures design (Experiment 2), when participants themselves believed advice not to be valid (Experiment 3), and even after full debriefing about invalid advice (Experiment 4). Lay advice exerted a similar influence as expert advice (Experiment 5). Although these provocative results are independent of numeracy and consensus (Experiment 6), they highlight the impact of metacognitive myopia as an impediment of social rationality.     

Beyond fear: rapid spatial orienting toward positive emotional stimuli

There is much empirical evidence for modulation of attention by negative -- particularly fear-relevant -- emotional stimuli. This modulation is often explained in terms of a fear module. Appraisal theories of emotion posit a more general mechanism, predicting attention capture by stimuli that are relevant for the needs and goals of the organism, regardless of valence. To examine the brain-activation patterns underlying attentional modulation, we recorded event-related potentials from 20 subjects performing a dot-probe task in which the cues were fear-inducing and nurturance-inducing stimuli (i.e., anger faces and baby faces). Highly similar validity modulation was found for the P1 time-locked to target onset, indicating early attentional capture by both positive and negative emotional stimuli. Topographic segmentation analysis and source localization indicate that the same amplification process is involved whether attention orienting is triggered by negative, fear-relevant stimuli or positive, nurturance-relevant stimuli. These results confirm that biological relevance, and not exclusively fear, produces an automatic spatial orienting toward the location of a stimulus.     

Age differences in dual-task performance after practice

This study investigated whether older adults could acquire the ability to perform 2 cognitive operations in parallel in a paradigm in which young adults had been shown to be able to do so (K. Oberauer & R. Kliegl, 2004). Twelve young and 12 older adults practiced a numerical and a visuospatial continuous memory updating task in single-task and dual-task conditions for 16 to 24 sessions. After practice, 9 young adults were able to process the 2 tasks without dual-task costs, but none of the older adults had reached the criterion of parallel processing. The results suggest a qualitative difference between young and older adults in how they approach dual-task situations.     

Midlife decline in declarative memory consolidation is correlated with a decline in slow wave sleep

Sleep architecture as well as memory function are strongly age dependent. Slow wave sleep (SWS), in particular, decreases dramatically with increasing age, starting already beyond the age of 30. SWS normally predominates during early nocturnal sleep and is implicated in declarative memory consolidation. However, the consequences of changes in sleep across the life span for sleep-associated memory consolidation have not been evaluated so far. Here, we compared declarative memory consolidation (for word-pair associates) during sleep in young and middle-aged healthy humans. The age groups (18–25 vs. 48–55 yr) did not differ with regard to learning performance before retention periods that covered, respectively, the first and second half of nocturnal sleep. However, after early retention sleep, where the younger subjects showed distinctly more SWS than the middle-aged (62.3 ± 3.7 min vs. 18.4 ± 7.2 min, P < 0.001), retrieval of the word pairs in the middle-aged was clearly worse than in the young (P < 0.001). In contrast, declarative memory retention did not differ between groups after late sleep, where retention was generally worse than after early sleep (P = 0.005). Retention of declarative memories was the same in both age groups when sleep periods containing equal amounts of SWS were compared, i.e., across late sleep in the young and across early sleep in the middle-aged. Our results indicate a decline in sleep-associated declarative memory consolidation that develops already during midlife and is associated with a decrease in early nocturnal SWS.