The role of mask coherence in motion-induced blindness

Motion-induced blindness (MIB) is the perceived disappearance of a salient target when surrounded by a moving mask. Much research has focused on the role of target characteristics on perceived disappearance by a coherently moving mask. However, we asked a different question: mainly, are there certain characteristics about the mask that can impact disappearance? To address this, we behaviorally tested whether MIB is enhanced or reduced by the property of common fate. In experiments 1, 2, and 3, we systematically manipulated the motion coherence of the mask and measured the amount of target disappearance. Results showed that, as mask coherence increased, perceived target disappearance decreased. This pattern was unaffected by the lifetime of the moving dots, the dot density of the motion stimulus, or the target eccentricity. In experiment 4, we investigated whether the number of motion directions contained in an incoherent mask could account for our findings. Using masks containing 1, 3, and 5 motion directions, we found that disappearance did not increase proportionally to the number of motion directions. We discuss our findings in line with current proposed mechanisms of MIB.     

Halt and recovery of illusory motion perception from peripherally viewed static images

We quantitatively investigated the halt and recovery of illusory motion perception in static images. With steady fixation, participants viewed images causing four different motion illusions. The results showed that the time courses of the Fraser-Wilcox illusion and the modified Fraser-Wilcox illusion (i.e., "Rotating Snakes") were very similar, while the Ouchi and Enigma illusions showed quite a different trend. When participants viewed images causing the Fraser-Wilcox illusion and the modified Fraser-Wilcox illusion, they typically experienced disappearance of the illusory motion within several seconds. After a variable interstimulus interval (ISI), the images were presented again in the same retinal position. The magnitude of the illusory motion from the second image presentation increased as the ISI became longer. This suggests that the same adaptation process either directly causes or attenuates both the Fraser-Wilcox illusion and the modified Fraser-Wilcox illusion.     

Natural Disaster and Risk of Psychiatric Disorders in Puerto Rican Children

We examined the persistence of psychiatric disorders at approximately 18 and 30 months after a hurricane among a random sample of the child and adolescent population (4–17 years) of Puerto Rico. Data were obtained from caretaker-child dyads (N = 1,886) through in person interviews with primary caretakers (all children) and youth (11–17 years) using the Diagnostic Interview Schedule for Children IV in Spanish. Logistic regressions, controlling for sociodemographic variables, were used to study the relation between disaster exposure and internalizing, externalizing, or any disorder. Children’s disaster-related distress manifested as internalizing disorders, rather than as externalizing disorders at 18 months post-disaster. At 30 months, there was no longer a significant difference in rates of disorder between hurricane-exposed and non-exposed youth. Results were similar across age ranges. Rates of specific internalizing disorders between exposed and unexposed children are provided. Research and clinical implications are discussed.     

The shared leadership process in decision-making teams

The present study examined the process of shared leadership in 45 ad hoc decision-making teams. Each team member's leadership behavior (n = 180) was assessed by behaviorally coding videotapes of the teams' discussions. The within-team patterns of leadership behavior were examined using cluster analysis. Results indicated that the likelihood of a team experiencing a full range of leadership behavior increased to the extent that multiple team members shared leadership, and that teams with shared leadership experienced less conflict, greater consensus, and higher intragroup trust and cohesion than teams without shared leadership. This study supports previous findings that shared leadership contributes to overall team functioning, and begins to delineate the extent to which team members may naturally share leadership.     

Perceived partner support in pregnancy predicts lower maternal and infant distress

Maternal postpartum emotional distress is quite common and can pose significant risk to mothers and infants. The current study investigated mothers' relationships with their partners during pregnancy and tested the hypotheses that perception of prenatal partner support is a significant predictor of changes in maternal emotional distress from midpregnancy to postpartum, and contributes to maternal ratings of infant distress to novelty. Using a prospective longitudinal design, 272 adult pregnant women were interviewed regarding their partner support, relationship satisfaction, and interpersonal security (attachment style and willingness to seek out support), and they completed standardized measures of prenatal symptoms of depression and anxiety (distress). At 6 to 8 weeks' postpartum, mothers reported these symptoms again and completed measures of their infants' temperament. Structural equation modeling (SEM) was used to test direct and indirect contributions of partner support, relationship satisfaction, and interpersonal security to maternal and infant postpartum distress. Mothers who perceived stronger social support from their partners midpregnancy had lower emotional distress postpartum after controlling for their distress in early pregnancy, and their infants were reported to be less distressed in response to novelty. Partner support mediated the effects of mothers' interpersonal security and relationship satisfaction on maternal and infant outcomes. A high-quality, supportive partner relationship during pregnancy may contribute to improved maternal and infant well-being postpartum, indicating a potential role for partner relationships in mental health interventions, with possible benefits for infants as well.     

Internet administration of paper-and-pencil questionnaires used in couple research: assessing psychometric equivalence

This study examined the psychometric equivalence of paper-and-pencil and Internet formats of key questionnaires used in couple research. Self-report questionnaires assessing interpersonal constructs (relationship satisfaction, communication/conflict management, partner support, emotional intimacy) and intrapersonal constructs (individual traits, psychological symptoms, contextual influences) were administered to young adults in committed dating relationships. The same measures were administered twice via paper-and-pencil and/or Internet methods over a 2-week period. Method order was counterbalanced among participants, and temporal stability was controlled. Intrapersonal and interpersonal measures generally remained reliable when administered online and demonstrated quantitative and qualitative equivalence across methods. The implications of online administration of questionnaires are discussed, and specific recommendations are made for researchers who wish to transition to online data collection.     

Under what conditions would people be willing to make a living organ donation?

The aim was to examine the factors involved in people's willingness to make a living organ donation. A convenience sample of 200 people in southern France rated willingness to be a living donor in 48 scenarios consisting of all combinations of five factors: recipient's identity (close family member and city resident); donor's surgical risk (little and some); donor's possible long-term health consequences (none, some lessening over time, and durable); transplant success ("generally durably successful" and "durably successful one time out of two"); and likelihood of other donors (subject is one of the rare compatible donors or one among others). Cluster analyses showed the existence of three distinct organ donation philosophies. For the largest cluster (49% of participants), willingness to donate was very high to a family member, but low to a city resident. For the second cluster (37%), willingness was high to family, but also moderately high to a city resident. For the third cluster (14%), willingness was always low. Thus, most participants judged themselves ready to make a living organ donation to a family member and many even to a stranger.     

Optische Versuche über Ruhe und Bewegung

Ohne Zusammenfassung Mit 20 Textabbildungen. Dissertation der Naturwissenschaftlichen Fakult?t Frankfurt a. M.