Selective influence of second target exposure duration and Task1 load effects in the attentional blink phenomenon

The purpose of the experiments was to constrain the locus of interference in the attentional blink (AB) paradigm. Two visual stimuli, T₁ and T₂, were shown 300 msec apart, and each was followed by a mask. T₁ was an “H,” an “S,” an “ &, ” or a blank field; T₂ consisted of five letters. In Task₁, blank fields and & characters could be ignored, whereas Hs and Ss had to be identified and reported. Task₂ was always to report as many letters as possible from T₂. Task₂ performance was lower when T₁ had to be reported, as expected from the attentional blink phenomenon (AB). The exposure duration of T₂ was also manipulated. More letters could be reported as exposure duration was increased. However, this effect was additive with manipulations of Task₁ processing load that produced the AB effect. Log-linear analyses assuming that effects of T₂ exposure duration and Task₁ load effects occur at functionally distinct stages of processing provided satisfactory fits to the results, suggesting that none of the AB effect occurs as early as those of T₂ exposure duration. The results suggest that the locus of the AB effect is later than the stage(s) of processing affected by exposure duration.     

Dementia and the Neurovirulence of HIV-1

Infection with human immunodeficiency virus type 1 (HIV-1) leads rapidly to infection of the brain and subsequent neuropsychological impairment, including subclinical impairment, minor cognitive-motor disorder, and HIV-1-associated dementia (HAD). This article reviews HAD and the factors involved in its pathogenesis; the effectiveness of antiretroviral therapy; the prevalence of HIV-1 and subtypes; and the role of chemokines and cytokines as the capstones associated with neuropathology due to inflammation.     

Attachment and borderline personality disorder

The author outlines his concept of reflective function or mentalization, which is defined as the capacity to think about mental states in oneself and in others. He presents evidence to suggest that the capacity for reflective awareness in a child's caregiver increases the likelihood of the child's secure attachment, which in turn facilitates the development of mentalization in the child. He proposes that a secure attachment relationship offers the child a chance to explore the mind of the caregiver, and in this way to learn about minds; he formulates this model of the birth of the psychological self as a variation on the Cartesian cogito: "My caregiver thinks of me as thinking and therefore I exist as a thinker." This model is then applied to provide insight into some personality-disordered individuals who were victims of childhood abuse. The author proposes (1) that individuals who experience early trauma may defensively inhibit their capacity to mentalize to avoid having to think about their caregiver's wish to harm them; and (2) that some characteristics of severe borderline personality disorder may be rooted in developmental pathology associated with this inhibition. He offers evidence for and some qualifications of this model, and argues that the therapeutic effect of psychoanalysis depends on its capacity to activate patients' ability to evolve an awareness of mental states and thus find meaning in their own and other people's behavior.     

Emotional states and physical health

Positive emotional states may promote healthy perceptions, beliefs, and physical well-being itself. To explore potential mechanisms linking pleasant feelings and good health, the authors consider several lines of research, including (a) direct effects of positive affect on physiology, especially the immune system, (b) the information value of emotional experiences, (c) the psychological resources engendered by positive feeling states, (d) the ways in which mood can motivate health-relevant behaviors, and (e) the elicitation of social support. As anticipated by the Greek physician Hippocrates, positive emotions and healthy outcomes may be linked through multiple pathways.     

The positive and negative of human expertise in gaze perception

Judging where others look is crucial for many social and cognitive functions. Past accounts of gaze perception emphasize geometrical cues from the seen eye. Human eyes have a unique morphology, with a large white surround (sclera) to the dark iris that may have evolved to enhance gaze processing. Here we show that the contrast polarity of seen eyes has a powerful influence on gaze perception. Adult observers are highly inaccurate in judging gaze direction for images of human eyes with negative contrast polarity (regardless of whether the surrounding face is positive or negative), even though negative images of eyes preserve the geometric properties of positives that are judged accurately. The detrimental effect of negative contrast polarity is much larger for gaze perception than for other directional judgements (e.g. judging which way a head is turned). These results suggest an 'expert' system for gaze perception, which always treats the darker region of a seen eye as the part that does the looking.     

Illusory inferences from a disjunction of conditionals: a new mental models account

(Johnson-Laird, P.N., & Savary, F. (1999, Illusory inferences: a novel class of erroneous deductions. Cognition, 71, 191-229.) have recently presented a mental models account, based on the so-called principle of truth, for the occurrence of inferences that are compelling but invalid. This article presents an alternative account of the illusory inferences resulting from a disjunction of conditionals. In accordance with our modified theory of mental models of the conditional, we show that the way individuals represent conditionals leads them to misinterpret the locus of the disjunction and prevents them from drawing conclusions from a false conditional, thus accounting for the compelling character of the illusory inference.     

Keeping track: the function of the current state buffer

The Current State Buffer has been proposed to account for our ability to keep track of significant stimuli in our immediate environment. The three experiments reported here were designed to test the independence of the Current State Buffer from the established components of Working Memory. Pre-schoolers were used in order to minimize the possible interference of other memory structures and complex strategies on the part of the subjects, thus allowing a cleaner test of the hypotheses. In the experiments, 180 pre-schoolers watched an Emu glove puppet tidy away toys into receptacles (the 'Tidy Emu Paradigm'), such that the number of pairings just exceeded their capacity for recall of the locations of toys in receptacles. We take this task to be a prototypical visuospatial Working Memory task. In the Object condition of Experiment 1, a Teddy was an object and was tidied away with the other toys. In the Character condition the Teddy was an animated character who interacted with the children and then went to sleep in one of the receptacles. Where Teddy was a character, all children remembered his location even though they had not been asked to; when he was an object only half of the children were correct despite explicit instructions to remember. More crucially, the location of the other toys was better recalled for children in the Character condition than those in the Object condition. These data are taken as evidence for the independence of the Current State Buffer from the Visuospatial Sketchpad. Other explanations, such as a von Restorff effect, are considered, and Experiments 2 and 3 test and reject these as possibilities.     

Demographic, clinical, and neurocognitive correlates of everyday functional impairment in severe mental illness

Although cognitive deficits often accompany severe mental illness, their implications for everyday functioning remain poorly understood. In this study, an occupational therapist (OT) rated the everyday functioning of 105 adult psychiatric patients. Using demographic, clinical, and cognitive variables, the authors tested alternative models to account for the observed variability in OT ratings. Although age, education, and the presence of schizophrenia each contributed to a model that accounted for 27% of the variation in functional independence, adding terms for auditory divided attention and verbal learning increased the proportion of explained variance to 45% and decreased the beta weights for age and education--but not schizophrenia--to nonsignificant levels. These findings demonstrate the relevance of cognitive performance to everyday functioning in severe mental illness. They are discussed with respect to hypothesized determinants of psychiatric disability.     

Evidence for role-neutral initial processing of metaphors

Two models of metaphor processing are contrasted. The structure-mapping model postulates an initially role-neutral alignment process, followed by directional projection of inferences. The attributive categorization model postulates role-specific processing throughout comprehension. To test between these models, the early stages of metaphor comprehension were probed using a technique based on S. Glucksberg, P. Gildea, and H. Bookin's (1982) finding that metaphorical meaning interferes with literal truthfulness judgments. In Experiment 1, interference effects did not differ between normal metaphors and metaphors with reversed terms, suggesting that initial processing is role-neutral. In Experiment 2, we again found no role dependence in interference effects, even for highly conventional metaphors. In Experiment 3, it was verified that (a) full comprehension is role-sensitive and (b) full comprehension reaction times (RTs) are far longer than interference RTs, buttressing the claim that interference is an early-stage effect. Overall, the results support the structure-mapping model of metaphor processing.