Selecting the Right Tool For the Job

There are competing ethical concerns when it comes to designing any clinical research study. Clinical trials of possible treatments for Ebola virus are no exception. If anything, the competing ethical concerns are exacerbated in trying to find answers to a deadly, rapidly spreading, infectious disease. The primary goal of current research is to identify experimental therapies that can cure Ebola or cure it with reasonable probability in infected individuals. Pursuit of that goal must be methodologically sound, practical and consistent with prevailing norms governing human subjects research. Some maintain that only randomized controlled trials (RCTs) with a placebo or standard-of-care arm can meet these conditions. We maintain that there are alternative trial designs that can do so as well and that sometimes these are preferable to RCTs.     

False predictions about the detectability of visual changes: the role of beliefs about attention,memory, and the continuity of attended objects in causing change blindness blindness

Recently, a number of experiments have emphasized the degree to which subjects fail to detect large changes in visual scenes. This finding, referred to as "change blindness," is often considered surprising because many people have the intuition that such changes should be easy to detect. documented this intuition by showing that the majority of subjects believe they would notice changes that are actually very rarely detected. Thus subjects exhibit a metacognitive error we refer to as "change blindness blindness." Here, we test whether CBB is caused by a misestimation of the perceptual experience associated with visual changes and show that it persists even when the pre- and postchange views are separated by long delays. In addition, subjects overestimate their change detection ability both when the relevant changes are illustrated by still pictures, and when they are illustrated using videos showing the changes occurring in real time. We conclude that CBB is a robust phenomenon that cannot be accounted for by failure to understand the specific perceptual experience associated with a change.     

Relationship of Prosody Perception to Personality and Aggression

One-hundred-fifteen participants (73 female, 42 male) were evaluated for prosody, or vocal emotion, perception, personality factors, relational aggression and physical aggression. The male participants reported higher levels of physical aggression, and the female participants reported greater Neuroticism, consistent with other data. For the male participants, better perception of prosody was related to both greater Extraversion and greater Conscientiousness, all involved in interpersonal functioning. These relationships were not found in the female participants, but there was a relationship between perception of prosody and relational aggression. Women who were better at perceiving the emotional status of others based on vocal cues were less relationally aggressive. Perhaps greater relational aggression reflects a poor adaptation to diminished ability to perceive emotional status.     

Scene structure enhances change detection

Theories of objects recognition, scene perception, and neural representation of scenes imply that jumbling a coherent scene should reduce change detection. However, evidence from the change detection literature questions whether jumbling affects change detection. The experiments reported here demonstrate that jumbling does, in fact, reduce change detection. In Experiments 1 and 2, change detection was better for normal scenes than for jumbled scenes. In Experiment 3, inversion failed to interfere with change detection, demonstrating that the disruption of surface and object continuity inherent to jumbling is responsible for reduced change detection. These findings provide a crucial commonality between change detection research and theories of scene perception and neural representation. We also discuss why previous research may have failed to find effects of jumbling.     

An empirical investigation of the statistical properties of generalized single-case randomization tests

Adapting Edgington's [J. Psychol. 90 (1975) 57] randomly determined intervention start-point model, Levin and Wampold [Sch. Psychol. Quart. 14 (1999) 59] proposed a set of nonparametric randomization tests for analyzing the data from single-case designs. In the present study, the performance of Levin and Wampold's four basic tests (independent start-point general and comparative effectiveness, simultaneous start-point general and comparative effectiveness) was examined with respect to their Type I error rates and statistical power. Of Levin and Wampold's four tests, all except the independent start-point comparative effectiveness test maintained their empirical Type I error rates and had acceptable power at larger sample-size and effect-size combinations. The one-tailed comparative intervention effectiveness test for the independent start-point model was found to be too liberal, in that it did not maintain its Type I error rate. Although a two-tailed application of that test was found to be conservative at longer series lengths, it had acceptable power at larger sample-size and effect-size combinations. The results support the utility of a versatile new class of single-case designs that permit both within- and between-unit statistical assessments of intervention effectiveness.     

Perceived Group Status Differences and the Effects of Gender, Ethnicity, and Religion on Social Dominance Orientation

Social dominance orientation (SDO) is a measure of general desire for group-based dominance. According to social dominance theory, the higher the status of one's group, the higher one's level of SDO should be. This study examined the extent to which between-group differences in SDO increase as the size of the perceived status gap between the groups increases. Data were collected in Israel, Northern Ireland, and the United States. In agreement with expectations, differences in SDO between arbitrary-set groups (e.g., ethnic and religious groups) were found to be greater when the status gap between the groups was perceived to be larger. In contrast, gender differences in SDO did not vary as a function of the size of the perceived status gap between men and women: Men had higher levels of SDO than women even when the gender status gap was perceived to be very small. These findings highlight the effects of perceived group status on SDO and the degree to which these effects vary depending on whether the salient group distinction is based on gender, ethnicity, or religion.     

Comparison of grasping movements made by healthy subjects in a 3-dimensional immersive virtual versus physical environment

Virtual reality (VR) technology is being used with increasing frequency as a training medium for motor rehabilitation. However, before addressing training effectiveness in virtual environments (VEs), it is necessary to identify if movements made in such environments are kinematically similar to those made in physical environments (PEs) and the effect of provision of haptic feedback on these movement patterns. These questions are important since reach-to-grasp movements may be inaccurate when visual or haptic feedback is altered or absent. Our goal was to compare kinematics of reaching and grasping movements to three objects performed in an immersive three-dimensional (3D) VE with haptic feedback (cyberglove/grasp system) viewed through a head-mounted display to those made in an equivalent physical environment (PE). We also compared movements in PE made with and without wearing the cyberglove/grasp haptic feedback system. Ten healthy subjects (8 women, 62.1 ± 8.8 years) reached and grasped objects requiring 3 different grasp types (can, diameter 65.6 mm, cylindrical grasp; screwdriver, diameter 31.6 mm, power grasp; pen, diameter 7.5 mm, precision grasp) in PE and visually similar virtual objects in VE. Temporal and spatial arm and trunk kinematics were analyzed. Movements were slower and grip apertures were wider when wearing the glove in both the PE and the VE compared to movements made in the PE without the glove. When wearing the glove, subjects used similar reaching trajectories in both environments, preserved the coordination between reaching and grasping and scaled grip aperture to object size for the larger object (cylindrical grasp). However, in VE compared to PE, movements were slower and had longer deceleration times, elbow extension was greater when reaching to the smallest object and apertures were wider for the power and precision grip tasks. Overall, the differences in spatial and temporal kinematics of movements between environments were greater than those due only to wearing the cyberglove/grasp system. Differences in movement kinematics due to the viewing environment were likely due to a lack of prior experience with the virtual environment, an uncertainty of object location and the restricted field-of-view when wearing the head-mounted display. The results can be used to inform the design and disposition of objects within 3D VEs for the study of the control of prehension and for upper limb rehabilitation.     

Traumatization,Marital Adjustment,and Parenting among Veterans and Their Spouses: A Longitudinal Study of Reciprocal Relations

Despite considerable research on secondary traumatization, the ramifications of veterans’ and their wives’ posttraumatic stress symptoms (PTSS) for the family system remain largely uninvestigated. Beginning to fill this gap, the current study aims to investigate the reciprocal relations between both spouses’ PTSS and marital adjustment, and the implications these bear for their parental functioning. Two hundred and twenty‐five Israeli veterans (mean age = 58.62, SD = 7.6) from the 1973 Yom Kippur War and their wives (mean age = 58.28, SD = 5.79) were examined at two points in time: 30 (T1) and 35–37 years after the war (T2). Analysis included longitudinal actor–partner interdependence modeling and sequential mediation analyses. The results show that higher PTSS among the wives at T1 predicted higher PTSS among husbands at T2, and vice versa, and predicted their husbands’ marital adjustment at T2. Moreover, wives’ PTSS at T1 had a significant effect on parental overinvolvement of both parents at T2, but neither their PTSS nor their husbands’ PTSS had an impact on positive parenting. In the intrapersonal domain, better marital adjustment at T1 predicted positive parenting among both spouses in subsequent measurement. Interpersonally, wives’ lower marital adjustment at T1 predicted husbands’ higher parental functioning, but not vice versa. Furthermore, marital adjustment mediated the association between PTSS and positive parenting for both spouses. The results emphasize the detrimental ramifications of war trauma on the interpersonal domains in veterans’ families. Hence, both marital and parental consequences of trauma should be considered in clinical family interventions.     

Depression and anxious apprehension distinguish frontocingulate cortical activity during top-down attentional control

A network consisting of left dorsolateral prefrontal cortex (LDLPFC) and dorsal anterior cingulate cortex (dACC) has been implicated in top-down attentional control. Few studies have systematically investigated how this network is altered in psychopathology, despite evidence that depression and anxiety are associated with attentional control impairments. Functional MRI and dense-array event-related brain potential (ERP) data were collected in separate sessions from 100 participants during a color-word Stroop task. Functional MRI results guided ERP source modeling to characterize the time course of activity in LDLPFC (300-440 ms) and dACC (520-680 ms). At low levels of depression, LDLPFC activity was indirectly related to Stroop interference and only via dACC activity. In contrast, at high levels of depression, dACC did not play an intervening role, and increased LDLPFC activity was directly related to decreased Stroop interference. Specific to high levels of anxious apprehension, higher dACC activity was related to more Stroop interference. Results indicate that depression and anxious apprehension modulate temporally and functionally distinct aspects of the frontocingulate network involved in top-down attention control.