A recurrent connectionist model of group biases

Major biases and stereotypes in group judgments are reviewed and modeled from a recurrent connectionist perspective. These biases are in the areas of group impression formation (illusory correlation), group differentiation (accentuation), stereotype change (dispersed vs. concentrated distribution of inconsistent information), and group homogeneity. All these phenomena are illustrated with well-known experiments, and simulated with an autoassociative network architecture with linear activation update and delta learning algorithm for adjusting the connection weights. All the biases were successfully reproduced in the simulations. The discussion centers on how the particular simulation specifications compare with other models of group biases and how they may be used to develop novel hypotheses for testing the connectionist modeling approach and, more generally, for improving theorizing in the field of social biases and stereotype change.     

Underemployment in America: Measurement and Evidence

An important way in which employment hardship has come to be conceptualized and measured is as underemployment. Underemployment goes beyond mere unemployment (being out of a job and looking for work), to include those who have given up looking for work, part-time workers whose employer(s) cannot give them full-time work, and the working poor. To provide needed background for the other articles in this special issue, we trace the history of the concept of underemployment, review existing empirical literature, offer a critique of the measurement of underemployment as conventionally operationalized, and provide up-to-date evidence on the trends and correlates of underemployment in the United States.     

Temporal integration of speech prosody is shaped by language experience: an fMRI study

Differences in hemispheric functions underlying speech perception may be related to the size of temporal integration windows over which prosodic features (e.g., pitch) span in the speech signal. Chinese tone and intonation, both signaled by variations in pitch contours, span over shorter (local) and longer (global) temporal domains, respectively. This cross-linguistic (Chinese and English) study uses functional magnetic resonance imaging to show that pitch contours associated with tones are processed in the left hemisphere by Chinese listeners only, whereas pitch contours associated with intonation are processed predominantly in the right hemisphere. These findings argue against the view that all aspects of speech prosody are lateralized to the right hemisphere, and promote the idea that varying-sized temporal integration windows reflect a neurobiological adaptation to meet the 'prosodic needs' of a particular language.     

Inflated and contradictory category naming deficits in Alzheimer's disease?

Although some studies have documented category-specific deficits in patients with Alzheimer's disease, others have not. One possible reason is that where control groups have been used in previous studies, they have performed at ceiling; and this may spuriously affect the incidence and type of deficit reported (especially with common statistical techniques such as z-scores). We examined this issue in 18 Alzheimer's patients and 26 elderly controls, who named two picture sets: a simple set that typically produces ceiling effects (Set 1) and one that produces a normal distribution in controls (Set 2). Sets 1 and 2 produced inconsistent and even contradictory deficits in the same patients. The results also show that ceiling effects may inflate the number of living thing deficits and hence, distort the reported ratio of living to nonliving cases.     

Dynamic variations in affective priming

The present study investigates the dynamics of emotional processing and awareness using an affective facial priming paradigm in conjunction with a multimodal assessment of awareness. Key facial primes are visually masked, and are presented for brief (unconscious) and extended (conscious) durations. Using a preference measure, we examine whether the effects of the primes differ qualitatively (Murphy & Zajonc, 1993). We show that: (a) unconscious affective priming with faces emerges strongly in initial presentations and diminishes rapidly with repetition; (b) conscious affective priming also emerges strongly in initial presentations, however it persists in strength with repetition; and (c) in contrast to other reports on the salience of negative stimuli, happy faces appear more salient than sad faces when presented outside awareness. We discuss the limits and extensions of unconscious affective priming with faces, and consider several methodological and conceptual questions concerning emotional processing out of awareness.     

Differentiating location- and distance-based processes in memory for time: An ERP study

Memory for the time of events may benefit from reconstructive, location-based, and distance-based processes, but these processes are difficult to dissociate with behavioral methods. Neuropsychological research has emphasized the contribution of prefrontal brain mechanisms to memory for time but has not clearly differentiated location- from distance-based processing. The present experiment recorded event-related brain potentials (ERPs) while subjects completed two different temporal memory tests, designed to emphasize either location- or distance-based processing. The subjects’ reports of locationbased versus distance-based strategies and the reaction time pattern validated our experimental manipulation. Late (800–1,800 msec) frontal ERP effects were related to location-based processing. The results provide support for a two-process theory of memory for time and suggest that frontal memory mechanisms are specifically related to reconstructive, location-based processing.     

Are UN Peacekeepers at Risk for Suicide?

Media reports connecting UN peacekeeping duties by Canadian soldiers to their subsequent suicide prompted this study of peacekeeping as suicide risk. In a case-control design we retrospectively compared 66 suicides in the Canadian military between 1990 and 1995 with two control groups: (a) 2,601 controls randomly selected from the electronic military database and (b) 66 matched controls with complete personnel and medical data. We found no increased risk of suicide in peacekeepers except among a subgroup of air force personnel. Here confounding individual factors, isolation from supports, and possibly inadequate preparation for deployment elucidated their suicides. Theater of deployment (e.g., Bosnia) did not affect the suicide rate. Military suicides experienced psychosocial stresses and psychiatric illness more often than their matched controls. We conclude that although peacekeeping per se does not increase overall suicide risk, military life-styles may strain interpersonal relationships, encourage alcohol abuse, and contribute to psychiatric illness and suicide in a minority of vulnerable individuals irrespective of peacekeeping assignment. Careful selection, and preparatory military training that encourages intragroup bonding and mutual support, may protect against suicide risk.     

Self-injurious behavior: gene-brain-behavior relationships

This paper summarizes a conference held at the National Institute of Child Health and Human Development on December 6-7, 1999, on self-injurious behavior [SIB] in developmental disabilities. Twenty-six of the top researchers in the U.S. from this field representing 13 different disciplines discussed environmental mechanisms, epidemiology, behavioral and pharmacological intervention strategies, neurochemical substrates, genetic syndromes in which SIB is a prominent behavioral phenotype, neurobiological and neurodevelopmental factors affecting SIB in humans as well as a variety of animal models of SIB. Findings over the last decade, especially new discoveries since 1995, were emphasized. SIB is a rapidly growing area of scientific interest to both basic and applied researchers. In many respects it is a model for the study of gene-brain-behavior relationships in developmental disabilities.     

Anxiety, signal anxiety, and unconscious anticipation: neuroscientific evidence for an unconscious signal function in humans

A central tenet of psychoanalysis, and arguably of any comprehensive theory of mind, is the existence of a psychological unconscious. Years of clinical investigation into the nature of unconscious processes have facilitated the development of psychoanalysis as a clinical method. Empirical investigations of unconscious mental processes, however, have lagged behind clinical inquiry. With few exceptions, attempts to understand unconscious processes using rigorous experimental controls have remained sequestered in scientific domains other than psychoanalysis, where they have proliferated recently. In view of this recent upsurge of research on unconscious processes outside of psychoanalysis, efforts to integrate such knowledge into general theories of psychopathology and clinical investigation are critical. In this paper, an interdisciplinary approach is taken to the study of one aspect of unconscious mental functioning--what Freud originally termed signal anxiety. Signal anxiety is examined using information from cognitive psychology and learning theory, psychophysiology, behavioral neuroscience, and psychoanalytic theory. Though the original concept of signal anxiety is supported by recent research, it is concluded that signal anxiety is probably best thought of not as the affect of anxiety but as a subset of unconscious mental processes that have a signal function of anticipating danger. Such unconscious anticipatory processes are a general feature of the mind that includes responses to both real and imagined (neurotic) appraisals of a situation. The neurophysiological structures and processes associated with unconscious anticipation in humans are just beginning to be understood.