Producing high-dimensional semantic spaces from lexical co-occurrence

A procedure that processes a corpus of text and produces numeric vectors containing information about its meanings for each word is presented. This procedure is applied to a large corpus of natural language text taken from Usenet, and the resulting vectors are examined to determine what information is contained within them. These vectors provide the coordinates in a high-dimensional space in which word relationships can be analyzed. Analyses of both vector similarity and multidimensional scaling demonstrate that there is significant semantic information carried in the vectors. A comparison of vector similarity with human reaction times in a single-word priming experiment is presented. These vectors provide the basis for a representational model of semantic memory, hyperspace analogue to language (HAL).     

Quine, Analyticity and Philosophy of Mathematics

Quine correctly argues that Carnap's distinction between internal and external questions rests on a distinction between analytic and synthetic, which Quine rejects. I argue that Quine needs something like Carnap's distinction to enable him to explain the obviousness of elementary mathematics, while at the same time continuing to maintain as he does that the ultimate ground for holding mathematics to be a body of truths lies in the contribution that mathematics makes to our overall scientific theory of the world. Quine's arguments against the analytic/synthetic distinction, even if fully accepted, still leave room for a notion of pragmatic analyticity sufficient for the indicated purpose.     

Race,psychosocial vulnerability and social support differences in inner-city women's symptoms of posttraumatic stress disorder

Background/Objectives: Inner-city Black women may be more susceptible to posttraumatic stress disorder (PTSD) than White women, although mechanisms underlying this association are unclear. Living in urban neighborhoods distinguished by higher chronic stress may contribute to racial differences in women's cognitive, affective, and social vulnerabilities, leading to greater trauma-related distress including PTSD. Yet social support could buffer the negative effects of psychosocial vulnerabilities on women's health. Methods/Design: Mediation and moderated mediation models were tested with 371 inner-city women, including psychosocial vulnerability (i.e., catastrophizing, anger, social undermining) mediating the pathway between race and PTSD, and social support moderating psychosocial vulnerability and PTSD. Results: Despite comparable rates of trauma, Black women reported higher vulnerability and PTSD symptoms, and lower support compared to White Hispanic and non-Hispanic women. Psychosocial vulnerability mediated the pathway between race and PTSD, and social support moderated vulnerability, reducing negative effects on PTSD. When examining associations by race, the moderation effect remained significant for Black women only. Conclusions: Altogether these psychosocial vulnerabilities represent one potential mechanism explaining Black women's greater risk of PTSD, although cumulative psychosocial vulnerability may be buffered by social support. Despite higher support, inner-city White women's psychosocial vulnerability may actually outweigh support's benefits for reducing trauma-related distress.     

Anxiety and cognitive efficiency: Differential modulation of transient and sustained neural activity during a working memory task

According to the processing-efficiency hypothesis (Eysenck, Derakshan, Santos, & Calvo, 2007), anxious individuals are thought to require greater activation of brain systems supporting cognitive control (e.g.,dorsolateral prefrontal cortex; DLPFC) in order to maintain equivalent performance to nonanxious subjects. A recent theory of cognitive control (Braver, Gray, & Burgess, 2007) has proposed that reduced cognitive efficiency might occur as a result of changes in the temporal dynamics of DLPFC recruitment. In this study, we used a mixed blocked/ event-related fMRI design to track transient and sustained activity in DLPFC while high- and low-anxious participants performed a working memory task. The task was performed after the participants viewed videos designed to induce neutral or anxiety-related moods. After the neutral video, the high-anxious participants had reduced sustained but increased transient activation in working memory areas, in comparison with low-anxious participants. The high-anxious group also showed extensive reductions in sustained activation of "default-network" areas (possible deactivation). After the negative video,the low-anxiety group shifted their activation dynamics in cognitive control regions to resemble those of the high-anxious group. These results suggest that reduced cognitive control in anxiety might be due to a transient, rather than sustained, pattern of working memory recruitment. Supplementary information for this study may be found at www.psychonomic.org/archive.     

Sleep arrangements and night waking at 6 and 12 months in relation to infants' stress‐induced cortisol responses

The objective of this short‐term longitudinal study was to examine the concurrent and prospective associations of infants' sleep arrangements and night waking with cortisol responses to an inoculation at 6 and 12 months, controlling for several key covariates. To our knowledge, this was the first study to concurrently and prospectively link proximity in sleep arrangements and night waking to physiological stress reactivity. A sample of 92 mother–infant dyads participated in the study when the infants were 6 and 12 months of age, although sample sizes were reduced for some analyses. Both proximal cosleeping arrangements and more frequent night wakings' were associated concurrently with an increased cortisol response to inoculations at both ages. Night waking at 6 months also was associated with a slightly increased cortisol response to inoculation at 12 months. Results aimed at exploring the direction of influence suggested that cosleeping and night waking may influence infant stress physiology rather than the reverse. Adaptive and maladaptive implications of infants' nocturnal experiences and greater stress‐induced cortisol responses are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

The social psychological power of photography: can the image‐freezing machine make something of nothing?

Sontag ( 1990 ) proposed that taking a photograph imparts social significance to the moment being captured. Two experiments were conducted to examine how the experience of being photographed affects the social relations of those who are photographed. In Experiment 1 (N=92), unacquainted members of dyads who were photographed together and then saw the resulting image displayed greater social self‐categorization and greater affinity for each other than did dyads who were not photographed (p<0.05). In Experiment 2 (N=282), pairs of photographed strangers also displayed greater social self‐categorization and mutual affinity than pairs of nonphotographed strangers (p<0.05). This effect occurred whether pair members were explicitly framed together in photographs or not. This result was unaffected by whether the photographed strangers were shown or were not shown their photograph. Merely opening and closing the shutter of a camera was sufficient for the development of a photo‐bonding effect. Results are discussed in terms of how the experience of being photographed can affect interpersonal perception and relationship formation. The significance of being photographed (Milgram, 1977 ; Sontag, 1990 ) apparently is so strong that it promotes social self‐categorization (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987 ) both when people are photographed simultaneously and sequentially. Copyright © 2000 John Wiley & Sons, Ltd.     

Changes in the incidental context impacts search but not loading of the motor buffer

During a retention test, a change in the nature of the incidental contextual information present during training can have a deleterious impact on response selection by not activating particular subsets of information in memory that help direct the retrieval process. The present experiment addressed whether a change in the incidental context also impacted the completion of processes associated with loading and searching the motor buffer during motor programming. A self-select paradigm was used to describe the planning and execution of one- and four-element sequences that consisted of short and long duration key-presses. During a test phase following training, changes in the incidental contextual information impeded the search of the motor buffer. However, loading specific timing information into the motor buffer was unaffected by shifts in contexts. These data support the contention that contextual information plays a fundamental role in a broad array of movement-planning operations that involve search and retrieval type activity.