EMG activity in selected target muscles during imagery rising on tiptoes in healthy adults and poststroke hemiparetic patients

The authors sought to gain further knowledge about activation of target muscles during imagery engagement in a motor task. Six hemiparetic patients and 9 healthy participants performed 3 real rises on tiptoes and then, after pausing, 3 imagery rises on tiptoes. Metronome beats guided the rate of rises and descents. Electromyographic (EMG) activity from the medial gastrocnemius and the rectus femoris muscles were monitored bilaterally throughout the performance of both tasks. In 3 healthy participants and 3 individuals with hemiparesis, EMG activity was related to the imagery task in at least 1 of the target muscles. Conversely, in the other participants, motor imagery practice was not accompanied by task-related EMG activity in the monitored muscles. In all cases, the increment in activation level during motor imagery practice was very low in comparison with that of real performance. The findings were not unequivocal; therefore, EMG activity may sometimes, but not always, be recorded during motor imagery practice both in healthy individuals and in poststroke hemiparetic participants. Further research is needed to align motor imagery practice with the objectives of motor rehabilitation.     

Voluntary and involuntary attention vary as a function of impulsivity

In the present study we examined, first, whether voluntary and involuntary attention manifest differently in people who differ in impulsivity (measured with the Barratt Impulsivity Scale). For Experiment 1, we used the spatial cueing task with informative and noninformative spatial cues to probe voluntary and involuntary attention, respectively. We found that participants with high impulsivity scores exhibited larger involuntary attention effects, whereas participants with low impulsivity scores exhibited larger voluntary attention effects. For Experiment 2, we used the correlated-flanker task to determine whether the differences between groups in Experiment 1 were due to high-impulsive participants being less sensitive to the display contingencies or to high-impulsive participants having a greater spread of spatial attention. Surprisingly, high-impulsive participants showed a greater sensitivity to contingencies in the environment (correlated-flanker effect). Our results illustrate one situation in which involuntary attention associated with high impulsivity can play a useful role.     

The multifinality constraints effect: how goal multiplicity narrows the means set to a focal end

In the presence of several objectives, goal conflict may be avoided via multifinal means, which advance all of the active goals at once. Because such means observe multiple constraints, they are fewer in number than the unconstrained means to a single goal. Five experimental studies investigated the process of choosing or generating such means for multiple goals. We found that the simultaneous activation of multiple goals restricted the set of acceptable means to ones that benefitted (or at least, did not harm) the entire set of active goals. Two moderators of this phenomenon were identified: (a) the feasibility of identifying multifinal means, which was dependent on the relations between the different active goals, and (b) the enhanced importance of the focal goal, which resulted in the inhibition of its alternatives and the consequent relaxation of multifinality constraints.     

Mechanisms of motivation–cognition interaction: challenges and opportunities

Recent years have seen a rejuvenation of interest in studies of motivation–cognition interactions arising from many different areas of psychology and neuroscience. The present issue of Cognitive, Affective, & Behavioral Neuroscience provides a sampling of some of the latest research from a number of these different areas. In this introductory article, we provide an overview of the current state of the field, in terms of key research developments and candidate neural mechanisms receiving focused investigation as potential sources of motivation–cognition interaction. However, our primary goal is conceptual: to highlight the distinct perspectives taken by different research areas, in terms of how motivation is defined, the relevant dimensions and dissociations that are emphasized, and the theoretical questions being targeted. Together, these distinctions present both challenges and opportunities for efforts aiming toward a more unified and cross-disciplinary approach. We identify a set of pressing research questions calling for this sort of cross-disciplinary approach, with the explicit goal of encouraging integrative and collaborative investigations directed toward them.     

Applying the Bootstrap to Taxometric Analysis: Generating Empirical Sampling Distributions to Help Interpret Results

Meehl's taxometric method was developed to distinguish categorical and continuous constructs. However, taxometric output can be difficult to interpret because expected results for realistic data conditions and differing procedural implementations have not been derived analytically or studied through rigorous simulations. By applying bootstrap methodology, one can generate empirical sampling distributions of taxometric results using data–based estimates of relevant population parameters. We present iterative algorithms for creating bootstrap samples of taxonic and dimensional comparison data that reproduce important features of the research data with good precision and negligible bias. In a series of studies, we demonstrate the utility of these comparison data as an interpretive aid in taxometric research. Strengths and limitations of the approach are discussed along with directions for future research.     

Self-Determination and Resource Rights: In Defence of Territorial Jurisdiction Over Natural Resources

Is territorial jurisdiction over natural resources justified? This paper argues that a freedom-based account of self-determination coupled with ‘functionalist’ justifications of territorial right support territorial jurisdiction over natural resources. This justification simultaneously gives rise to limits on the permissible exercise of the right: the principles of reciprocity and generality, and of equal freedom. This ‘reciprocal’ view on territorial jurisdiction over natural resources, defended here, differs from two alternatives: the traditional sovereignty view on the one hand and the transnational jurisdiction view—which favours the transfer of sovereignty over natural resources from states to transnational institutions—on the other hand.     

Relations Between the Development of Teaching and Theory of Mind in Early Childhood

The relations among children’s theory of mind (ToM), their understanding of the intentionality of teaching, and their own peer teaching strategies were tested. Seventy-five 3-, 4-, and 5-year-olds completed 11 ToM and understanding-of-teaching tasks. Subsequently, 30 of the children were randomly chosen to teach a peer how to play a board game, and their teaching strategies and levels of contingent teaching were recorded. There were developmental changes in the children’s understanding of teaching as an intentional activity. When teaching their peers, 3-year-olds used demonstration, whereas 4- and 5-year-olds added verbal explanations and began to adapt contingently to the learners’ changing knowledge level. Relations among ToM, understanding of teaching, and teaching level were found. The results suggest that the development of children’s teaching strategies and their contingency are closely tied to the development of ToM.     

The “Brightening” Effect: Reactions to Positive Events in the Daily Lives of Individuals With Major Depressive Disorder and Generalized Anxiety Disorder

Depressed individuals are less reactive than healthy individuals to positive stimuli in the laboratory, but accumulating evidence suggests that they are more emotionally reactive to positive events in their daily lives. The present study probed the boundaries of this curious “mood brightening” effect and investigated its specificity to major depressive disorder (MDD) vis-à-vis generalized anxiety disorder (GAD), its closest boundary condition. We used ecological momentary assessment to measure reactions to positive events over one week in individuals with MDD (n = 38), GAD (n = 36), comorbid MDD-GAD (n = 38), and no psychopathology (n = 33). Depressed individuals responded to positive events with larger changes in affect, cognition, reported withdrawal (but not approach) behavior, and symptoms than healthy controls. More severe depression assessed before the sampling week predicted greater brightening. Altered reactivity to positive events was relatively specific to MDD when compared with GAD, similar to patterns found for other positive emotional processes. The robustness, scope, and relative specificity of the brightening effect highlights the need to resolve conflicting findings across laboratory and non-laboratory studies to advance understanding of altered reactivity in emotional disorders.     

Categories and Dimensions

ABSTRACT— The distinction between categories and dimensions has important consequences for basic and applied science in many areas of psychological research. Decisions as to whether individuals should be assigned to groups or located along one or more continua often are based on personal preferences or discipline-specific measurement traditions, which can lead to the creation, use, or reification of spurious categories or dimensions. Methods for evaluating the latent structure of psychological constructs, using powerful and informative tests between competing models, are available. Rather than choosing on a priori grounds, investigators can perform structural research to evaluate the strength and consistency with which results tease apart categorical and dimensional models. Here, we review why researchers should make this distinction empirically, briefly discuss methods available for doing so, and describe the breadth of areas ripe for exploiting the largely untapped potential of structural research.