Aging and visual 3-D shape recognition from motion

Two experiments were conducted to evaluate the ability of younger and older adults to recognize 3-D object shape from patterns of optical motion. In Experiment 1, participants were required to identify dotted surfaces that rotated in depth (i.e., surface structure portrayed using the kinetic depth effect). The task difficulty was manipulated by limiting the surface point lifetimes within the stimulus apparent motion sequences. In Experiment 2, the participants identified solid, naturally shaped objects (replicas of bell peppers, Capsicum annuum) that were defined by occlusion boundary contours, patterns of specular highlights, or combined optical patterns containing both boundary contours and specular highlights. Significant and adverse effects of increased age were found in both experiments. Despite the fact that previous research has found that increases in age do not reduce solid shape discrimination, our current results indicated that the same conclusion does not hold for shape identification. We demonstrated that aging results in a reduction in the ability to visually recognize 3-D shape independent of how the 3-D structure is defined (motions of isolated points, deformations of smooth optical fields containing specular highlights, etc.).     

The displaced aggression questionnaire

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to engage in displaced aggression). The trait measure demonstrated good internal consistency and test-retest reliability as well as convergent and discriminant construct validity. Unlike other related personality measures, trait displaced aggression significantly predicted indirect indicators of real-world displaced aggression (i.e., self-reported domestic abuse and road rage) as well as laboratory displaced aggression in 2 experiments.     

The role of uncertainty in the systematic spatial mislocalization of moving objects

It only makes sense to talk about the position of a moving object if one specifies the time at which its position is of interest. The authors here show that when a flash or tone specifies the moment of interest, subjects estimate the moving object to be closer to where it passes the fixation point and further in its direction of motion than it really is. The authors propose that these biases arise from a combination of a large temporal uncertainty, a temporal asymmetry related to sampling the moving object's position, and a bias toward believing that one is looking at what one sees.     

Impact forces cannot explain the one-target advantage in rapid aimed hand movements

A pointing movement is executed faster when a subject is allowed to stop at the first target than when the subject has to proceed to a second target ("one-target advantage"). Our hypothesis was that this is because the impact at the target helps to stop the finger when the finger does not have to proceed to a second target. This hypothesis would predict that the horizontal force at contact with the first target should be larger when there is only one-target. Modelling smooth movements with larger forces at contact using a minimum-jerk model, shows that the peak velocity is slightly higher and it occurs later during the movement when there is only one target. Although the one-target advantage was present in our experiment, the horizontal force at contact in the one-target condition was not larger than in the two-target condition. The time of the maximum velocity did not differ, but the maximum velocity was higher in the one-target condition. Thus our hypothesis is rejected, favouring a non-mechanical explanation of the one-target advantage.     

Outpatient group psychotherapy following day treatment for patients with personality disorders

This prospective, naturalistic study evaluated the practice and effectiveness of an outpatient group therapy program following day treatment for patients with personality disorders (PDs). One hundred and eighty-seven patients (86% patients with PDs and 14% with no PDs), were treated in outpatient psychodynamic group therapy. Outcome was assessed by Global Assessment of Functioning, Symptom Check List 90-R, and Inventory of Interpersonal Problems-Circumplex, short version, at admission and discharge from day treatment, and at the end of outpatient group therapy. Average length of outpatient therapy was 24 months. Forty-three percent terminated in an irregular manner. Outcome of the continuation therapy was satisfactory for patients without PDs. For PD patients, the improvement from the day treatment was maintained during outpatient therapy, but further improvements were modest for symptoms and interpersonal distress, somewhat better for global functioning. Implications for further treatment development are discussed.     

Comparing the sensitivity of manual pursuit and perceptual judgments to pictorial depth effects

Abstract - We examined whether a pictorial depth illusion influences the manual pursuit of a moving dot to the same extent that it influences the dot's apparent displacement. Fourteen subjects performed two tasks. In one case, they used their unseen hand to track a dot that moved on an elliptical path. In the other, they first watched the dot move on the same path, and then set an ellipse to match the shape of the dot's path. The illusion influenced the two tasks to the same extent, suggesting that the visual information processing is the same for the two tasks.     

Chewing on it can chew you up: effects of rumination on triggered displaced aggression

Ruminating about a provocation increases the likelihood of displaced aggression following a minor annoyance (trigger). In Study 1, provoked participants who ruminated for 25 min were more aggressive toward a fumbling confederate than were distracted participants. Provocation-induced negative affect was positively related to aggression but only among those who ruminated. Study 2 conceptually replicated Study 1 and also found that the more negatively people reacted to the trigger, the more likely the trigger was to increase displaced aggression. Study 3 replicated the findings of Studies 1 and 2 by using an 8-hr rumination period. All 3 studies suggest that ruminating about a provocation increases the likelihood that a minor triggering annoyance will increase displaced aggression.     

Perception of acceleration with short presentation times: can acceleration be used in interception?

To investigate whether visual judgments of acceleration could be used for intercepting moving targets, we determined how well subjects can detect acceleration when the presentation time is short. In a differential judgment task, two dots were presented successively. One dot accelerated and the other decelerated. Subjects had to indicate which of the two accelerated. In an absolute judgment task, subjects had to adjust the motion of a dot so that it appeared to move at a constant velocity. The results for the two tasks were similar. For most subjects, we could determine a detection threshold even when the presentation time was only 300 msec. However, an analysis of these thresholds suggests that subjects did not detect the acceleration itself but that they detected that a target had accelerated on the basis of the change in velocity between the beginning and the end of the presentation. A change of about 25% was needed to detect acceleration with reasonable confidence. Perhaps the simplest use of acceleration for interception consists of distinguishing between acceleration and deceleration of the optic projection of an approaching ball to determine whether one has to run backward or forward to catch it. We examined the results of a real ball-catching task (Oudejans, Michaels, & Bakker, 1997) and found that subjects reacted before acceleration could have been detected. We conclude that acceleration is not used in this simple manner to intercept moving targets.     

The influence of chromatic and achromatic variability on chromatic induction and perceived colour

Judgments of the colour of a surface are influenced by the colour of the surrounding. To determine whether only the average colour of the surrounding matters, or also the chromatic variability, judgments in colourful scenes are often compared with ones in which a target is surrounded by a plain background that provides the same average physical illumination of the retina as the colourful scene. The variability sometimes makes a difference (eg Shevell and Wei, 1998 Vision Research 38 1561-1566), and sometimes it does not (eg Brenner and Cornelissen, 1998 Vision Research 38 1789-1793). Is this because of the nonlinearity in cone responses? We designed scenes that stimulated the cones in an equivalent manner, both on average and in terms of variability, and yet differed markedly in chromatic variability. The more colourful surroundings had considerably less influence on subjects' colour judgments. We conclude that early cone-specific regulation of sensitivity cannot be responsible for the change in perceived colour, and deduce that chromatic induction takes place after contrast gain control.