Adding fear to conflict: A general purpose cognitive control network is modulated by trait anxiety

Studies of cognitive control show that the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex are involved in the detection and resolution of cognitive conflict. However, the neural and behavioral mechanisms underlying emotional interference effects are less consistent. We used fMRI during emotional and nonemotional versions of a facial Stroop task to investigate the effects of emotional stimuli on cognitive control. In the full group there was limited evidence that different prefrontal circuits manage conflict arising from emotional and nonemotional distractors. However, individual differences in trait anxiety affected both behavioral performance and neural activity during the emotional task. Relative to low-anxiety (LA) subjects, high-anxiety (HA) subjects showed greater amygdala activity to task-relevant emotional information and impaired performance and greater conflict-related activity in the dACC when emotional content was task-irrelevant. Only LA subjects activated rostral ACC during the emotional task. This is consistent with cognitive models of individual differences that hypothesize deficient control of task-irrelevant emotional information in HA subjects. Additional behavioral and fMRI results from this study may be downloaded from http://cabn.psychonomic-journals .org/content/supplemental.     

Structuralism as a philosophy of mathematical practice

This paper compares the statement ‘Mathematics is the study of structure’ with the actual practice of mathematics. We present two examples from contemporary mathematical practice where the notion of structure plays different roles. In the first case a structure is defined over a certain set. It is argued firstly that this set may not be regarded as a structure and secondly that what is important to mathematical practice is the relation that exists between the structure and the set. In the second case, from algebraic topology, one point is that an object can be a place in different structures. Which structure one chooses to place the object in depends on what one wishes to do with it. Overall the paper argues that mathematics certainly deals with structures, but that structures may not be all there is to mathematics. I wish to thank Colin McLarty as well as the anonymous referees for helpful comments on earlier versions of this paper.     

"Just looking at food makes me gain weight": experimental induction of thought-shape fusion in eating-disordered and non-eating-disordered women

Thought-shape fusion (TSF) is a cognitive distortion that can be induced experimentally and is associated with eating pathology. The current study was conducted in order to elucidate the effects of TSF induction in females with eating disorders (n=35), as well as in restrained eaters (n=38) and unrestrained eaters (n=39). It was hypothesized that TSF induction would result in anxiety, guilt, increased feelings of fatness, perceived weight gain and feelings of moral wrong-doing relative to an anxiety and control induction. It was further hypothesized that restrained eaters and individuals with eating disorders would exhibit a stronger reaction to a TSF induction than would unrestrained eaters. The results indicated that, as predicted, TSF can be induced in individuals both with and without eating disorders, and individuals with eating disorders reported the highest levels of "state" TSF after the induction relative to the non-clinical controls. However, contrary to expectations, restrained eaters reported higher levels of perceived weight gain and moral wrong-doing after the anxiety induction (but not the TSF induction) relative to the control induction. Potential mechanisms for this pattern of results are discussed, and the clinical implications of research on TSF are also considered.     

It’s not just what you say but when you say it: Self-presentation and temporal construal

Three experiments demonstrated that the use and effectiveness of self-presentation strategies are affected by time. In Experiment 1, participants used more indirect self-presentation statements for the distant than near future, but used more direct self-presentation statements for the near than distant future. In Experiment 2, participants for whom indirect self-presentation strategies were made accessible rated a future interview as more temporally distant than those for whom direct self-presentation strategies were made accessible. In Experiment 3, participants rated their self-presentation attempts as more effective if they used direct strategies for the near future and indirect strategies for the distant future. Implications for studying the timing of self-presentation and its relation to temporal construal levels are discussed.     

Parental expressed emotion toward children: prediction from early family functioning

Expressed emotion (EE), an index of family member criticism and emotional overinvolvement, predicts outcome among adults and children with mental disorders. However, limited research exists on factors contributing to EE. Aims of the current study were to (a) examine EE in mothers of young children; (b) assess relationships between demographic factors and EE in a diverse sample; and (c) investigate whether family stress and functioning, including quality of marital relationship, life events, maternal stress, and family environment, predict EE. In the current study, 276 mothers completed questionnaires when their children were between 1 and 3 years of age and a measure of EE when their children were in kindergarten. Results indicated that family expressiveness was the most consistent predictor of EE. Further research seems warranted to better delineate associations between family functioning and EE.     

Telephone conversation impairs sustained visual attention via a central bottleneck

Recent research has shown that holding telephone conversations disrupts one’s driving ability. We asked whether this effect could be attributed to a visual attention impairment. In Experiment 1, participants conversed on a telephone or listened to a narrative while engaged in multiple object tracking (MOT), a task requiring sustained visual attention. We found that MOT was disrupted in the telephone conversation condition, relative to single-task MOT performance, but that listening to a narrative had no effect. In Experiment 2, we asked which component of conversation might be interfering with MOT performance. We replicated the conversation and single-task conditions of Experiment 1 and added two conditions in which participants heard a sequence of words over a telephone. In the shadowing condition, participants simply repeated each word in the sequence. In the generation condition, participants were asked to generate a new word based on each word in the sequence. Word generation interfered with MOT performance, but shadowing did not. The data indicate that telephone conversation disrupts attention at a central stage, the act of generating verbal stimuli, rather than at a peripheral stage, such as listening or speaking.     

Human and machine perception of biological motion

More than 30 years ago, Johansson was the first to show that humans are capable of recovering information about the identity and activity of animate creatures rapidly and reliably from very sparse visual inputs – the phenomenon of biological motion. He filmed human actors in a dark setting with just a few strategic points on the body marked by lights – so-called moving light displays (MLDs). Subjects viewing the MLDs reported a vivid impression of moving human forms, and were even able to tell the activity in which the perceived humans were engaged. Subsequently, the phenomenon has been widely studied and many attempts have been made to model and to understand it. Typical questions that arise are: How precisely is the sparse low-level information integrated over space and time to produce the global percept, and how important is world knowledge (e.g., about animal form, locomotion, gravity, etc.)? In an attempt to answer such questions, we have implemented a machine-perception model of biological motion. If the computational model can replicate human data then it might offer clues as to how humans achieve the task. In particular, if it can do so with no or minimal world knowledge then this knowledge cannot be essential to the perception of biological motion. To provide human data for training and against which to assess the model, an extensive psychophysical experiment was undertaken in which 93 subjects were shown 12 categories of MLDs (e.g., normal, walking backwards, inverted, random dots, etc.) and were asked to indicate the presence or absence of natural human motion. Machine perception models were then trained on normal sequences as positive data and random sequences as negative data. Two models were used: a k-nearest neighbour (k-NN) classifier as an exemplar of ‘lazy’ learning and a back-propagation neural network as an exemplar of ‘eager’ learning. We find that the k-NN classifier is better able to model the human data but it still fails to represent aspects of knowledge about body shape (especially how relative joint positions change under rotation) that appear to be important to human judgements.