Reward anticipation enhances brain activation during response inhibition

The chance to achieve a reward starts up the required neurobehavioral mechanisms to adapt our thoughts and actions in order to accomplish our objective. However, reward does not equally reinforce everybody but depends on interindividual motivational dispositions. Thus, immediate reward contingencies can modulate the cognitive process required for goal achievement, while individual differences in personality can affect this modulation. We aimed to test the interaction between inhibition-related brain response and motivational processing in a stop signal task by reward anticipation and whether individual differences in sensitivity to reward (SR) modulate such interaction. We analyzed the cognitive–motivational interaction between the brain pattern activation of the regions involved in correct and incorrect response inhibition and the association between such brain activations and SR scores. We also analyzed the behavioral effects of reward on both reaction times for the “go” trials before and after correct and incorrect inhibition in order to test error prediction performance and postinhibition adjustment. Our results show enhanced activation during response inhibition under reward contingencies in frontal, parietal, and subcortical areas. Moreover, activation of the right insula and the left putamen positively correlates with the SR scores. Finally, the possibility of reward outcome affects not only response inhibition performance (e.g., reducing stop signal reaction time), but also error prediction performance and postinhibition adjustment. Therefore, reward contingencies improve behavioral performance and enhance brain activation during response inhibition, and SR is related to brain activation. Our results suggest the conditions and factors that subserve cognitive control strategies in cognitive motivational interactions during response inhibition.     

Implicit Attitudes Reflect Associative,Non‐associative,and Non‐attitudinal Processes

It is a common assumption that responses on implicit measures are proxies for automatically activated associations stored in memory. Consequently, explanations for implicit attitude malleability, variability, and prediction have assumed differences in underlying associations. However, a growing body of evidence challenges the assumption that implicit attitude change is driven only by associative processes. This paper reviews evidence from research with the Quadruple Process model on the influence of associative and non‐associative processes on implicit task performance. We also describe recent research on non‐attitudinal processes that do not pertain directly to the attitude object of interest but that, nevertheless, influence implicit task performance. Implications for the interpretation of implicit measures and implicit attitude change are discussed.     

On Merely Modal Epistemic Peers: Challenging the Equal-Weight View

There is a controversy, within social epistemology, over how to handle disagreement among epistemic peers. Call this the problem of peer disagreement. There is a solution, i.e. the equal-weight view, which says that disagreement among epistemic peers is a reason for each peer to lower the credence they place in their respective positions. However, this solution is susceptible to a serious challenge. Call it the merely modal peers challenge. Throughout parts of modal space, which resemble the actual world almost completely, there are hordes of epistemic peers, who disagree with almost any arbitrarily chosen belief had by residents of the actual world. Further, the mere modality of these peers is not itself an epistemic difference-maker. Thus, on the equal-weight view, we should significantly lower the credence we place in most of our beliefs. Surely, this is seriously mistaken. Thus, there are serious considerations that cut against the equal-weight view.     

How do slender mineral crystals resist buckling in biological materials?

Mineral crystals in biological materials such as bone, tooth, and sea shell are susceptible to buckling under compressive loading due to their slender geometry with large aspect ratios. How does nature deal with this problem? This question is especially interesting in view of the three orders of magnitude difference in elastic modulus between protein and mineral. As a first analysis of this question, we study the stability of a single mineral platelet confined in an otherwise perfect protein–mineral nanostructure. We find that there exists a transition of buckling strength from an aspect ratio-dependent regime to a lower threshold value, independent of the crystal geometry. Typical values of the aspect ratio of mineral crystals of bone and nacre fall in this transition region. The existence of a buckling strength independent of the detailed geometrical parameters of mineral may be critically important from the point of view of structure robustness as the composite behaviour of biomaterials should not depend sensitively on small variations in crystal size and shape.     

Does Respect for Embryos Entail Respect for Gametes?

Respect for human embryos is often defended on the basis of the potentiality argument: embryos deserve respect because they already possess potentially the features that in adults are fully actualized. Opponents of this argument challenge it by claiming that if embryos should be respected because they are potentially adults, then gametes should be respected because they are potentially embryos. This article rejects this reductio ad absurdum argument by showing that there are two different types of potentiality involved so that the transitivity of potentiality does not hold up in this case. Respect for embryos does not logically entail respect for gametes.     

The selection of grammatical features in word production: the case of plural nouns in German

Two experiments investigate the effect of number congruency using picture-word interference. Native German participants were required to name pictures of single objects (Nase 'nose') or two instances of the same object (Nasen 'noses') while ignoring simultaneously presented distractor words. Distractor words either had the same number or were different in number. In addition, the type of plural formation (same or different inflectional plural suffix) and the semantic relationship (same or different semantic category) between target and distractor were varied in Experiments 1 and 2. Results showed no effect of number congruency in either experiment. Furthermore, the type of inflectional suffix did not exert an influence on naming latencies in Experiment 1, but semantic relationship led to a significant interference effect in Experiment 2. The results indicate that selection of the number feature diacritic in noun production is not a competitive process. The implications of the results for models of lexical access are discussed.     

Displacement activities as a behavioral measure of stress in nonhuman primates and human subjects

Traditionally, research on human stress has relied mostly on physiological and psychological measures with a relatively minor emphasis on the behavioral aspects of the phenomenon. Such an approach makes it difficult to develop valid animal models of the human stress syndrome. A promising approach to the study of the behavioral correlates of stress is to analyze those behavior patterns that ethologists have named displacement activities and that, in primates, consist mostly of self-directed behaviors. In both nonhuman primates and human subjects, displacement behavior appears in situations characterized by social tension and is likely to reflect increased autonomic arousal. Pharmacological studies of nonhuman primates have shown that the frequency of occurrence of displacement behavior is increased by anxiogenic compounds and decreased by anxiolytic drugs. Ethological studies of healthy persons and psychiatric patients during interviews have found that increased displacement behavior not only correlates with a subjective feeling state of anxiety and negative affect but also gives more veridical information about the subject's emotional state than verbal statements and facial expression. The measurement of displacement activities may be a useful complement to the physiological and psychological studies aimed at analyzing the correlates and consequences of stress.     

The absence of a gender congruency effect in romance languages: a matter of stimulus onset asynchrony?

Using the picture-word interference paradigm, H. Schriefers and E. Teruel (2000) found that in German the grammatical gender of the distractor word affects the production of phrases composed of article+picture name: Latencies were longer for picture-word pairs of different genders. However, the effect was found only at positive stimulus onset asynchronies (SOAs; i.e., when pictures were presented 75 or 150 ms earlier than word distractors). This gender congruency effect is not obtained in Romance languages. The present article examines whether in these languages, as in German, the effect appears at positive SOAs. No effect was observed in Italian and Spanish at positive SOAs. An account is proposed to explain why the gender congruency effect is obtained in Germanic (Dutch and German) but not in Romance languages.     

Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.