Direction-of-motion discrimination is facilitated by visible motion smear

Recent evidence indicates that motion smear can provide useful information for the detection and discrimination of motion. Further, it has been shown that the perception of motion smear depends critically on the density of dots in a random-dot (RD) stimulus. Therefore, in the present experiments, the contribution of perceived motion smear to direction-of-motion discrimination was evaluated using RD targets of different densities. Thresholds for direction-of-motion discrimination and the extent of perceived motion smear were determined for RD stimuli with densities of 1, 2, and 10 dots/deg(2), presented for 200 msec at a velocity of 4, 8, or 12 deg/sec. To evaluate the contribution of information about orientation from motion smear, thresholds for orientation discrimination were measured using parallel lines with the same length as the extent of perceived smear. Despite the opportunity for increased summation as RD density increases, our results indicate that direction-of-motion discrimination worsens. Because perception of motion smear is reduced with an increase in RD density, our results are consistent with a facilitation of direction-of-motion discrimination by visible motion smear.     

Book reviews

Islam: a challenge for Christianity (Concilium 1994/3). Hans Kung & Jurgen Moltmann (Eds), 1994. London, Concilium; Maryknoll, SCM Press; London, Orbis Books. 163 pp., pb. £8.95, ISBN 0–334–030269.

Cultures in Conflict: Christians, Muslims and Jews in the age of discovery. Bernard Lewis, 1995. New York, Oxford University Press. 101 pp., hb., $16.95, ISBN 0–19–509026–8.

Beyond Faith and Infidelity: the Sufi poetry and teachings of Mahmud Shabistari. L. Lewisohn, 1995. Richmond, Surrey, Curzon Press. 344 pp. pb. £14.99, 0–7007–0343–8.

The Prophet's Pulpit: Islamic preaching in contemporary Egypt. [Comparative Studies on Muslim Societies, 20]. Patrick Gaffney, 1994. Berkeley and Los Angeles, University of California Press. 367 pp., hb. £40.00, ISBN 0–520–08471–3, pb. £15.95, ISBN 0–520–08472–1.

Sufi and Scholar on the Desert Edge: Muhammad b. CA1i al‐Sanūsi and his Brotherhood. K. S. Vikor, 1995. London, Hurst & Co. 310 pp. hb. £37.50, ISBN 1 85065 218 X.

Children of Islam. Marie Parker‐Jenkins, 1995. Stoke‐on‐Trent, Trentham Books Ltd. 162 pp., £12.95, ISBN 1–85856 034 9.     

Examination of adolescents' negative thoughts, depressive mood, and family environment.

The focus of this study was the relationship among adolescents' negative thoughts, depressive mood, and family environment. Three hundred eleven students (aged 16 and 17 years) in public and private schools served as subjects. They were administered the Family Environment Scale, the Automatic Thoughts Questionnaire, and the Beck Depression Inventory. Family cohesion was found to be related to the degree of negative thoughts and depressive mood of the adolescents, but perceived control within the family was not.     

Responses to Depression in Children: Reconceptualizing the Relation Among Response Styles

We propose that researchers should utilize ratio scores when examining the response styles theory rather than examine each of the response styles separately. Higher ratio scores indicate a higher probability of engaging in ruminative, as opposed to distracting and problem solving, behaviors. In Phase One, we examined the factor structure and reliability of the Children's Response Styles Questionnaire (CRSQ) in a sample of 287 third through sixth grade schoolchildren. A two factor solution was obtained: (1) Rumination and (2) Distraction and Problem Solving. Both factors exhibited strong psychometric properties. In Phase Two, 140 children completed the CRSQ and the Children's Depression Inventory (CDI). Six weeks later, children completed the CDI. Confirmatory factor analysis indicated that the two-factor solution fit the data well. In line with hypotheses, CRSQ ratio scores were more strongly associated with CDI residual change scores than were either CRSQ rumination or distraction and problem solving scores.     

Terrorist threat and employees' perceived ability to cope with organizational change

This study investigated the impact of the perceived threat of terrorism on employees' ability to cope with organizational change as well as potentially underlying psychological mechanisms related to work satisfaction and initiative. Three days after the 2006 thwarted terrorist attacks in the United Kingdom, participants were reminded of terrorist threat (by pictures of terrorist attacks) reported lower levels in their ability to cope with organizational change, as well as lower levels of work satisfaction, than did participants who were not reminded of terrorist threat. Three months later, the same terror salience manipulation had no differential effect on these variables. Mediation analyses revealed that work satisfaction mediated the impact of terror salience on employees' ability to cope with organizational change.     

Physically Attractive Social Information Sources Lead to Increased Selective Exposure to Information

The present research investigated the impact of a social information source's physical attractiveness on selective exposure to decision-relevant information. In two studies, support was found for the hypothesis that physically attractive information sources lead decision makers into being more selective in both searching for (Studies 1 and 2; selective exposure) and evaluating (Study 2; biased assimilation) decision-relevant information. In both studies, the effect was driven by differences in the selection and evaluation of decision-consistent information, that is, physically attractive information sources led to increases in the perceived quality of decision-consistent information as well as increased selective exposure to this information. Theoretical and practical implications are discussed.     

How to Forget the Unforgettable? On Collective Trauma,Cultural Identity,and Mnemotechnologies

Nietzsche’s notion of “active forgetting” is employed to better understand the disruptive and destructive influence of collective trauma on cultural identity. Throughout the article genocide is taken as a cause of extreme trauma and used to illustrate this impact. Active forgetting in this context should not be confused with memories fading away; it is rather a positive and active force, a capacity which an individual, a society, or a culture needs to prosper. This notion provides guidance on how to banish the trauma to the extent that it ceases to paralyze the traumatized group. Technological skills that release negative emotions and ideas generated by the trauma from the collective memory—mnemotechnologies—are required to restore the capacity of forgetting.     

My role is my castle — The appeal of family roles after experiencing social exclusion

The present research investigated whether perceived social exclusion would lead women to embrace the social group of the family (and its traditional gender roles). In two studies, it was found that in comparison to a social inclusion manipulation, a social exclusion manipulation caused women to report significantly more positive inclinations towards traditional, gendered work allocations (Studies 1 and 2). Moreover, seeking meaning in life mediated the relationship between social exclusion and the perceived attractiveness of the roles of mother and housewife (Study 2). In a third study, adherence to family-related concepts was examined in both socially excluded and included men, but no difference was found between the two groups. It thus appears that social exclusion does not enhance the attractiveness of familial relationships for men. The theoretical and practical implications of these findings are discussed.     

Investigation of the computer experiences and attitudes of pre-service mathematics teachers: new evidence from Turkey

This study aimed to investigate the experiences of pre-service mathematics (PSM) teachers with computers and their attitudes toward them. The Computer Attitude Scale, Computer Competency Survey, and Computer Use Information Form were administered to 180 Turkish PSM teachers. Results revealed that most PSM teachers used computers at home and at Internet cafes, and that their competency was generally intermediate and upper level. The study concludes that PSM teachers' attitudes about computers differ according to their years of study, computer ownership, level of computer competency, frequency of computer use, computer experience, and whether they had attended a computer-aided instruction course. However, computer attitudes were not affected by gender.     

Brain imaging technologies as source for Extrospection: self-formation through critical self-identification

Phenomenology and the Cognitive Sciences - Brain imaging technologies are increasingly used to find networks and brain regions that are specific to the functional realization of particular aspects...