Visual perception of mean relative phase and phase variability

Perception of relative phase and phase variability may play a fundamental role in interlimb coordination. This study was designed to investigate the perception of relative phase and of phase variability and the stability of perception in each case. Observers judged the relative phasing of two circles rhythmically moving on a computer display. The circles moved from side to side, simulating movement in the frontoparallel plane, or increased and decreased in size, simulating movement in depth. Under each viewing condition, participants observed the same displays but were to judge either mean relative phase or phase variability. Phase variability interfered with the mean-relative-phase judgments, in particular when the mean relative phase was 0 degrees. Judgments of phase variability varied as a function of mean relative phase. Furthermore, the stability of the judgments followed an asymmetric inverted U-shaped relation with mean relative phase, as predicted by the Haken-Kelso-Bunz model.     

Distortions in definite distance and shape perception as measured by reaching without and with haptic feedback

Psychophysical studies reveal distortions in perception of distance and shape. Are reaches calibrated to eliminate distortions? Participants reached to the front, side, or back of a target sphere. In Experiment 1, feedforward reaches yielded distortion and outward drift. In Experiment 2, haptic feedback corrected distortions and instability. In Experiment 3, feedforward reaches with only haptic experience of targets replicated the shape distortions but drifted inward. This showed that outward drift in Experiment 1 was visually driven. In Experiment 4, visually guided reaches were accurate when participants used binocular vision but when they used monocular vision, reaches were distorted. Haptic feedback corrected inaccuracy and instability of distance but did not correct monocular shape distortions. Dynamic binocular vision is representative and accurate and merits further study.     

The information for catching fly balls: judging and intercepting virtual balls in a CAVE

Visually guided action implies the existence of information as well as a control law relating that information to movement. For ball catching, the Chapman Strategy--keeping constant the rate of change of the tangent of the elevation angle (d(tan(alpha))/dt)--leads a catcher to the right location at the right time to intercept a fly ball. Previous studies showed the ability to detect the information and the consistency of running patterns with the use of the strategy. However, only direct manipulation of information can show its use. Participants were asked to intercept virtual balls in a Cave Automated Virtual Environment (CAVE) or to judge whether balls would pass behind or in front of them. Catchers in the CAVE successfully intercepted virtual balls with their forehead. Furthermore, the timing of judgments was related to the patterns of changing d(tan(alpha))/dt. The advantages and disadvantages of a CAVE as a tool for studying interceptive action are discussed.     

Visual perception of the relative phasing of human limb movements

Studies of bimanual coordination have found that only two stable relative phases (0 degree and 180 degrees) are produced when a participant rhythmically moves two joints in different limbs at the same frequency. Increasing the frequency of oscillation causes an increase in relative phase variability in both of these phase modes. However, relative phasing at 180 degrees is more variable than relative phasing at 0 degree, and when the frequency of oscillation reaches a critical frequency, a transition to 0 degree occurs. These results have been replicated when 2 people have coordinated their respective limb movements using vision. This inspired us to investigate the visual perception of relative phase. In Experiment 1, recordings of human interlimb oscillations exhibiting different frequencies, mean relative phases, and different amounts of phase variability were used to generate computer displays of spheres oscillating either side to side in a frontoparallel plane or in depth. Participants judged the stability of relative phase. Judgments covaried with phase variability only when the mean phase was 0 degree or 180 degrees. Otherwise, judgments covaried with mean relative phase, even after extensive instruction and demonstration. In Experiment 2, mean relative phase and phase variability were manipulated independently via simulations, and participants were trained to perceive phase variability in testing sessions in which mean phase was held constant. The results of Experiment 1 were replicated. The HKB model was fitted to mean judgment standard deviations.     

Forgiveness in relation to attachment style and consanguine marriage in Iranian married individuals

The aim of this study was to compare forgiveness in secure and insecure Iranian married couples. Whether marriage had occurred within the family (consanguine) or not (non-consanguine) was also considered. 400 married participants completed the Family Forgiveness Scale and the Adult Attachment Questionnaire. Analysis of reported forgiveness within the marital family showed that, although there was no significant difference between secure and insecure participants in overall forgiveness, secure participants rated "reparation" and "resolution" higher, whereas insecure participants rated "realization" and "recognition" higher. Comparing the experience of forgiveness in the family of origin, securely attached couples not only reported significantly more overall forgiveness but reported more "realization" and "resolution" while forgiving. Some interesting sex differences were also found, as individuals in consanguine vs non-consanguine couples differed in mean "recognition" in the forgiveness process.     

Validation of the multicultural personality questionnaire in the context of personnel selection

The present data provide support for the reliability of the Multicultural Personality Questionnaire among a sample of job applicants (n=264). Factor analysis confirmed five factors: Cultural Empathy, Open‐Mindedness, Social Initiative, Flexibility, and Emotional Stability. Moreover, the data largely support the construct validity of the MPQ. Correlations with the Big Five were in the expected direction, and as predicted, Cultural Empathy and Social Initiative were both positively related to socially oriented vocational interests and Flexibility to artistic interests. Against our predictions, Cultural Empathy, Open‐Mindedness, and Flexibility appeared to be related to verbal intelligence. A comparable pattern of relations of the Big Five with intelligence and vocational interests was found. Finally, the MPQ scales predicted variance in an indicator of overall behaviour above the Big Five, supporting its incremental validity. Copyright © 2003 John Wiley & Sons, Ltd.     

Social change as an important goal or likely outcome: how regulatory focus affects commitment to collective action

The results of three experiments showed that regulatory focus influences the way in which the importance and likelihood of social change affect individuals' commitment to collective action. In Studies 1 (N= 82) and 2 (N= 153), the strength of participants' chronic regulatory focus was measured. In Study 3 (N= 52), promotion or prevention focus was experimentally induced. The results showed that for individuals under promotion focus, commitment to collective action depended on the perceived likelihood that through this action important social change would be achieved. Individuals under prevention focus were willing to commit to collective action when they attached high importance to its goal, regardless of the extent to which they believed that attainment of this goal was likely. Implications of these results for work on regulatory focus and collective action are discussed.     

Hand aperture patterns in prehension

Although variations in the standard prehensile pattern can be found in the literature, these alternative patterns have never been studied systematically. This was the goal of the current paper. Ten participants picked up objects with a pincer grip. Objects (3, 5, or 7cm in diameter) were placed at 30, 60, 90, or 120cm from the hands' starting location. Usually the hand was opened gradually to a maximum immediately followed by hand closing, called the standard hand opening pattern. In the alternative opening patterns the hand opening was bumpy, or the hand aperture stayed at a plateau before closing started. Two participants in particular delayed the start of grasping with respect to start of reaching, with the delay time increasing with object distance. For larger object distances and smaller object sizes, the bumpy and plateau hand opening patterns were used more often. We tentatively concluded that the alternative hand opening patterns extended the hand opening phase, to arrive at the appropriate hand aperture at the appropriate time to close the hand for grasping the object. Variations in hand opening patterns deserve attention because this might lead to new insights into the coordination of reaching and grasping.     

By any means necessary: the effects of regulatory focus and moral conviction on hostile and benevolent forms of collective action

In two studies, we investigate the effect of individuals' promotion and prevention focus on engagement in collective action. We show that responding to group-based disadvantage out of a sense of moral conviction motivates prevention-oriented- but not promotion-oriented- individuals to engage in collective action. Furthermore, holding such strong moral convictions about the fair treatment of their group causes the prevention-oriented to disregard societal rules against hostile forms of collective action (i.e., forms of action that are aimed at harming the interests of those held responsible for the group's disadvantage). Study 1 showed that prevention-oriented individuals, but not promotion-oriented individuals, with a strong moral conviction about the fair treatment of their group are willing to support both hostile and benevolent forms of collective action. Study 2 replicated this effect and showed that for prevention-oriented individuals but not for promotion-oriented individuals, holding a strong moral conviction about the fair treatment of the group overrides moral objections to hostile forms of collective action in the decision to support these forms of action.     

The developmental roots of the speed-accuracy trade-off

The speed of adult reaching movements is lawfully related to the distance of the reach and the size of the target. The authors had 7-, 9-, and 11-month-old infants reach for small and large targets to investigate a possible relation between the emergence of this speed-accuracy trade-off and the improvements in infants' ability to pick up tiny objects. By 7 months of age, infants slowed down their reaches for smaller objects. The authors concluded that it was not the ability to use a precision grip that facilitated the speed-accuracy trade-off but rather the other way around. The slowing down toward the end of the movement might set the conditions for the development of fine distal control of the hand.