Enhancing social diffusion theory as a basis for prevention intervention: A conceptual and strategic framework

Social diffusion theory has recently been recognized as a promising approach for large-scale disease prevention and health promotion efforts. This paper describes how principles and tactics from social cognitive theory, operant psychology, social psychology, social marketing, and the overarching stages of change model can be used to further develop the conceptual and strategic (technological) bases of social diffusion theory. Within an integrative framework, we discuss in detail more effective ways to train peer mediators of behavior change as one example of how social diffusion theory can benefit from this conceptual and strategic reformulation. We then further illustrate the use of peer mediators of change in human immunodeficiency virus (HIV) and cancer prevention intervention studies with both interventions training peer mediators to diffuse information, norms, and risk reduction strategies. Although the results of these studies showed reductions in high-risk behaviors across population segments, more closely following the framework discussed in this article should further increase the behavior change potential of future interventions based on social diffusion theory.     

Two bs or not two Bs? A signal detection theory analysis of repetition blindness in a counting task

Stimulus repetition usually benefits performance. A notable exception is repetition blindness (RB), in which subjects fail to report a repeated stimulus in a rapid serial visual presentation. Theories differ in attributing RB to either perceptual encoding or memory retrieval and to impaired discrimination versus response bias. In the present study, subjects judged whether one or two letters were imbedded in sequences of digits. Unlike previous studies, false guesses of two unrepeated letters were distinguished from false guesses of two repeated letters. When repeated- and unrepeated-letter trials were randomly intermixed (Experiment 1), RB was entirely attributable to response bias. However, when they were separately blocked (Experiments 2 and 3), RB was manifested in discriminability (d'). The results support perceptual-encoding accounts of RB but indicate that effects on discriminability depend on subjects' processing strategies.     

Recognition memory for source and occurrence: The importance of recollection

Previous recognition memory studies indicate that when both recollection and familiarity are expected to contribute to recognition performance (e.g., discriminating studied items from nonstudied items) the dual-process and the unequal-variance signal detection models provide comparable accounts of performance. When familiarity is not expected to be useful (e.g., when items from two equally familiar sources are discriminated between), the dual-process model provides a significantly better account of performance. In the present study, source recognition was tested under conditions in which familiarity could have been used to perform a list-discrimination task; participants were required to discriminate between strong studied items, weak studied items, and new items. The dual-process model provided a better account of performance than did the unequal-variance model. Moreover, the results indicated that the unequal-variance assumption in a single-process signal detection model was not a valid substitution for recollection and that recollection was used to make recognition judgments even when assessments of familiarity were useful.     

Perceptual assignment of opacity to translucent surfaces: the role of image blur

In constructing the percept of transparency, the visual system must decompose the light intensity at each image location into two components one for the partially transmissivc surface, the other for the underlying surface seen through it. Theories of perceptual transparency have typically assumed that this decomposition is defined quantitatively in terms of the inverse of some physical model (typically, Metelli's 'episcotister model'). In previous work, we demonstrated that the visual system uses Michelson contrast as a critical image variable in assigning transmittance to transparent surfaces not luminance differences as predicted by Metelli's model [F Metelli, 1974 Scientific American 230(4) 90 98]. In this paper, we study the contribution of another variable in determining perceived transmittance, namely, the image blur introduced by the light-scattering properties of translucent surfaces and materials. Experiment 1 demonstrates that increasing the degree of blur in the region of transparency leads to a lowering in perceived transmittance, even if Michelson contrast remains constant in this region. Experiment 2 tests how this addition of blur affects apparent contrast in the absence of perceived transparency. The results demonstrate that, although introducing blur leads to a lowering in apparent contrast, the magnitude of this decrease is relatively small, and not sufficient to explain the decrease in perceived transmittance observed in experiment 1. The visual system thus takes the presence of blur in the region of transparency as an additional image cue in assigning transmittance to partially transmissive surfaces.     

"Clockness" in the detection of dementia: a semantic-conceptual effect

We studied aspects of clock cognition that might underlie the sensitivity of the CDT in screening for dementia of the Alzheimer type (DAT). Two groups, 15 patients with mild-moderate DAT and 15 controls, were assessed with the CDT and specially designed tests of clock-related cognition. Patients were impaired on the CDT, but they did not differ from controls in copying a clock face or selecting the correct representation of a given time. Patients were worse than controls at distinguishing between clock and nonclock objects, detecting anomalies in clocks, and in setting time irrespective of response format. These findings suggest that semantic-conceptual aspects of clock-related cognition are important in discriminating between patients with DAT and controls.     

The research subject as wage earner

Theoretical Medicine and Bioethics - The practice of paying research subjects for participating inclinical trials has yet to receive an adequate moral analysis.Dickert and Grady argue for a wage...     

Video games and aggressive thoughts, feelings, and behavior in the laboratory and in life

Two studies examined violent video game effects on aggression-related variables. Study 1 found that real-life violent video game play was positively related to aggressive behavior and delinquency. The relation was stronger for individuals who are characteristically aggressive and for men. Academic achievement was negatively related to overall amount of time spent playing video games. In Study 2, laboratory exposure to a graphically violent video game increased aggressive thoughts and behavior. In both studies, men had a more hostile view of the world than did women. The results from both studies are consistent with the General Affective Aggression Model, which predicts that exposure to violent video games will increase aggressive behavior in both the short term (e.g., laboratory aggression) and the long term (e.g., delinquency).     

Hypermnesia: Age-related differences between young and older adults

Hypermnesia is a net improvement in memory performance that occurs across tests in a multitest paradigm with only one study session. Our goal was to identify possible age-related differences in hypermnesic recall. We observed hypermnesia for young adults using verbal (Experiment 1) as well as pictorial (Experiment 2) material, but no hypermnesia for older adults in either experiment. We found no age-related difference in reminiscence (Experiments 1 and 2), though there was a substantial difference in intertest forgetting (Experiments 1 and 2). Older, relative to young, adults produced more forgetting, most of which occurred between Tests 1 and 2 (Experiments 1 and 2). Furthermore, older, relative to young, adults produced more intrusions. We failed to identify a relationship between intrusions and intertest forgetting. We suggest that the age-related difference in intertest forgetting may be due to less efficient reinstatement of cues at test by older adults. The present findings reveal that intertest forgetting plays a critical role in hypermnesic recall, particularly for older adults.     

A family study of outpatients with borderline personality disorder and no history of mood disorder

While several studies have examined psychiatric disorders in the relatives of individuals with borderline personality disorder, many of these studies have not employed a family study methodology and suffer from other methodological shortcomings. Thus, the conclusions from family data addressing the validity of borderline personality disorder, its relation to other conditions, and its distinction from mood disorders, continue to be debated. The present investigation employed a family study design with direct interviews with relatives, structured diagnostic interviews with both probands and relatives, and blind assessment of relatives. Rates of psychiatric disorders were examined in 563 relatives of outpatients with mood disorders (n = 119), 54 relatives of outpatients with borderline personality disorder and no history of mood disorder (n = 11), and 229 relatives of never psychiatrically ill controls (n = 45). Results indicate increased rates of mood disorders and personality disorders in the relatives of borderline probands compared with never psychiatrically ill controls. Familial aggregation of psychiatric disorders was generally similar for borderline personality and the mood disorder comparison group. The results suggest there may be common etiological factors between borderline personality disorder and mood disorders.