The confirmability and disconfirmability of trait concepts revisited: Does content matter?

M. Rothbart and B. Park (1986) demonstrated that, consistent with the common negativity bias, positive traits are difficult to confirm and easy to disconfirm, whereas the opposite is true for negative traits. This article extends their analysis by showing that trait (dis-)confirmability is moderated by trait content (warmth vs. competence). Study 1 identifies a trait sample representative of warmth and competence. Study 2 shows a strong negativity effect for warmth and a reduced (or absent) negativity effect for competence. Study 3 examines trait properties related to the behavioral range of the trait possessor and to the motivational goals of the perceiver as predictors of trait (dis-)confirmability. The theoretical and practical implications of the authors' findings are discussed, and avenues for future research are suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In vivo assessment of neovascularization of liver metastases using perfusion CT

Neovascularization of tumours produces a high microvessel density. Although diagnostic imaging is unable to visualize microvessels directly, it is possible to demonstrate associated changes in tissue perfusion. The aim of this study was to use the quantitative functional information and high spatial resolution of perfusion computed tomography to study neovascularization of hepatic metastases. Perfusion CT was performed in 13 patients with hepatic metastases from various primary tumours. Arterial perfusion was measured in the metastasis; both arterial and portal perfusion were measured in a small rim of liver tissue immediately adjacent to the metastasis. Perfusion measurements were correlated against survival of the patient in nine cases. Arterial perfusion was increased above normal values, both in the metastasis (median: 0.62 ml min-1 ml-1; range: 0.26-3.05 ml min-1 ml-1) and in the adjacent liver (median: 0.51 ml min-1 ml-1; range: 0.14-1.60 ml min-1 ml-1). Portal perfusion of adjacent liver was highly variable (median: 0.30 ml min-1 ml-1; range: 0.05-1.85 ml min-1 ml-1). Arterial perfusion was positively correlated with portal perfusion within liver tissue adjacent to metastases (p < 0.05, r = 0.58), a reversal of the normal situation. Survival of the patient correlated with arterial perfusion within the metastasis (p < 0.05, r = 0.69) but more closely with arterial perfusion in the adjacent liver (p < 0.02, r = 0.78). In conclusion, alterations in perfusion within metastases and adjacent liver are in accordance with the histological features of neovascularization. Perfusion CT offers a method for studying neovascularization in the living patient and offers prognostic information.     

Cognitive Processes in Stereotype Formation: The Role of Correct Contingency Learning for Biased Group Judgments.

Three studies investigated contingency learning and stereotype formation in a scenario about group membership and behavior with a confounding context factor. The studies tested predictions from theoretical accounts of biased group judgments in terms of simplistic reasoning, parallel distributed memory, and pseudocontingencies. Study 1 revealed a positive correlation between erroneous stereotype formation and learning of the true contingencies with the confounding factor. Study 2 showed that a focus manipulation during encoding moderated the correlation between stereotype formation and contingency learning but not the strength of the erroneous stereotype. Study 3 used a quasiexperimental comparison between participants with biased versus unbiased group judgments and extended the findings of a positive relation between stereotype formation and contingency learning. The results support an explanation of biased group judgments by pseudocontingencies; that is, unwarranted inferences from accurately perceived bivariate correlations in complex environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of waterbeds on heart rate in preterm infants

The purpose of this study was to investigate the effects of waterbeds on heart rate (HR) in preterm infants. Subjects were 22 medically stable preterm infants. Across a 10-day study, HR was determined for a 1-hour period on each day. Baseline HRs with infants on the standard incubator mattress were obtained on the first 2 days of the study. They were then placed on the waterbed for 4 days. They were then returned to the incubator mattress and studied for 4 more days. Infants served as their own controls among baseline, on-waterbed (On-WB) and off-waterbed (Off-WB) periods. HR was determined by using a heart beat counting feature of the neonatal cardio-respiratory monitors. Analysis of variance revealed significant HR variability among subjects. There was no difference between baseline HR and on-waterbed HR. The HR increased when infants were transferred back to the standard mattress. The possibility that theophylline acted as a confound existed because doses were changed and levels varied for some subjects within the study period. Eight infants responded to the waterbed with lower HR during the On-WB period compared to the baseline (mean reduction = 5.7 bpm). The findings that HRs rose when the infants were returned to the incubator mattress are similar to those of a previous study. The subjects' reactivity to changes in treatment condition continues to confound the question as to whether waterbed therapy effects a reduction in HR. Since waterbeds have consistently resulted in soothing effects such as improved sleep and lowered activity, failure to produce a concomitant reduction in HR warrants attention toward other factors that may be determinants of heart rate. The high variability within and among subjects raises questions as to the usefulness of the HR variable for determining energy costs.     

Applying the realized probability of dying to cancer survival

Age comparisons of survival in cancer cohorts generally utilize relative survival rates, which are based on indicators of the probability of survival for a given number of years after diagnosis. Cancer relative survival rates for the same number of years tend to decline as age at diagnosis increases. However, the same number of years of survival reflects higher relative longevity at older ages than at younger ages. The realized probability of dying (RPD) is a survival measure that expresses individual survival time after diagnosis relative to the survival distribution of an age-, race-, and sex-specific reference population, in effect weighing individual survival time more heavily as age at diagnosis increases. The purpose of this study was to apply the RPD as a survival measure in cancer epidemiology. Two cohorts of cancer patients, white males with prostate cancer and white females with breast cancer, aged 55 years and over at diagnosis, were followed for 15 years. Although older subjects survived less time after diagnosis than younger subjects, they achieved more favorable RPD values. We present survival analysis methods for analyzing the RPD in this population, an approach not previously used with this measure. The implications for use of the RPD in cancer epidemiology are discussed.     

Input and central processing expressed in ERP and heart rate changes to rare target and rare nontarget stimuli

Whether late positive components of event-related potentials (ERPs) parallel changes in heart rate (HR) indicative of attention/orienting to rare stimuli has been debated. In the present study, a three-stimulus design was used, with rare target, rare nontarget, and frequent standard stimuli delivered under identical conditions except that instructions to subjects described the targets to which subjects should respond but did not describe the nontargets. In Experiment 1, stimuli varied among modalities; in Experiment 2, auditory stimuli were employed. Both ERPs and HR were consistent with automatic processing preceding two stages of controlled processing. Rare stimuli evoked larger parietal P300 and initial HR deceleration than standards. Presumably because of load-reducing effects of long interstimulus intervals, targets and nontargets were not distinguished before a late slow wave and a late phase of HR acceleration. Neither rare stimulus elicited a recognizable frontal P3a.