Secular Trends in Depressive Symptoms Among Norwegian Adolescents from 1992 to 2010

Several survey studies among adolescents have shown increasing rates of depressive symptoms over the last two to three decades. We know however little about mechanisms that might explain this increase. The present study uses data from three nationwide representative surveys of 16–17 year-old Norwegian adolescents that were conducted according to identical procedures in 1992, 2002, and 2010 (response rates 97.0, 91.0, 84.3 %, respectively). At each time point, approximately 3,000 adolescents participated (48.8 % girls and 51.2 % boys). Questionnaire data on depressive symptoms and a variety of potential risk and protective factors that might explain time trends in such symptoms were assessed at all time points. The results showed that the prevalence of high scores on depressive symptoms increased significantly between 1992 and 2002 among both boys and girls. No significant changes were observed between 2002 and 2010. The increase from 1992 to 2002 among girls and boys could be partially attributed to increases in eating problems and cannabis use, while reduced satisfaction with own appearance among girls contributed as well. Although the study does not provide information about the causal direction between putative risk factors and depressive symptoms, the results provide some indication that eating problems, cannabis use, and appearance related factors may contribute in explaining secular trends in depressive symptoms.     

The role of flicker and abrupt displacement in attention capture by motion onsets

Sunny and von Mühlenen (Psychonomic Bulletin & Review, 18, 1050–1056, 2011) showed that an onset of motion captured attention only when the motion was jerky (refreshed at 8 or 17 Hz), but not when it was smooth (33 or 100 Hz). However, it remained unclear why the onset of jerky motion captures attention. In the present study, we systematically tested the role of different aspects of jerky motion in capturing attention. Simple flicker without motion did not capture attention in the same way as jerky motion (Exp. 1). An abrupt displacement between 0.26° and 1.05° captured attention, irrespective of whether the stimulus subsequently continued to move smoothly (Exp. 2) or whether it remained stationary (Exps. 3 and 4). A displaced stimulus that was preceded briefly at the new location by a figure-8 placeholder did not capture attention (Exp. 5). These results are explained within a masking account, according to which abrupt onsets and abrupt displacements receive a processing advantage because they escape forward masking by the preceding figure-8 placeholders.     

Acquired equivalences between auditory stimuli in dolphins (Tursiops truncatus)

This study investigated whether dolphins would show evidence of equivalence class formation between auditory stimuli. Bottlenose dolphins were trained to press one or other of two response levers depending on which one of four auditory stimuli had been previously presented. Once they had learned the initial discriminations, the stimulus-lever contingencies was repeatedly reversed. Within any given session, however, pressing of one lever always led to reward with one set of two tones and pressing the other lever led to non-reward with an alternative set of two tones. After sufficient experience with this response reversal procedure, the dolphins spontaneously chose the same levers they had first learned to be correct with one of the across-set stimulus pairs when later in the session they were presented with the other of the across-set stimulus pairs. They thus demonstrated that they had associated the tones belonging to the two sets within two separate functional classes. It is discussed why the dolphins succeeded with auditory stimuli when they had previously failed in a similar task with visual stimuli. Received: 7 December 1999 / Accepted after revision: 23 June 2000     

Stimulus segmentation in the visual search task

Four experiments were conducted in order to study the segmentation process in a visual search task with relevant stimuli (target and distractors) randomly distributed among textural elements. The basic idea was that a parallel segmentation process of the relevant stimuli would contribute to the overall reaction time independently of the contribution of the number of relevant stimuli. In the first experiment, with relevant stimuli and textural elements that differed in the orientation of their component lines, texture presence interacted with number of relevant stimuli and with target presence. These results were not favorable to the parallel segmentation hypothesis. In the second and third experiments, in which the relevant and the textural stimuli differed in orientation and in the luminance contrast of their component lines, the results support a parallel segmentation process for the higher contrast conditions. In these experiments, the effect of texture presence was greater on target-absent than on target-present trials. Experiment 4 shows that the search can be restricted to the high-contrast relevant stimuli when the number of these stimuli is constant and the number of textural stimuli changes from trial to trial. The present results suggest that the relevant stimuli can be segmented in parallel and then submitted to a restricted analysis, even when they are scattered among textural stimuli.     

Visual perception of motion in depth: Application of a vector model to three-dot motion patterns

The aim of the present study was to identify spatial properties of three-dot motion patterns yielding perceived motion in depth. A proposed vector model analyzed each pattern in terms of common and relative motion components of the moving parts. The dots moved in straight paths in a frontoparallel plane. The Ss reported verbally what they perceived. The common motion did not affect the kénd of perceived event (translation or rotation in depth). Relative motions toward or away from a common point, i.e. concurrent motions, yielded perceived translatory motion in depth. Parallel relative motions toward or away from a common line generally yielded perceived rotation in depth. Complex motion patterns, consisting of concurrent and parallel relative motion components combined, evoked simultaneously perceived translation and rotation in depth under certain phase conditions of the components. Some limitations of the model were discussed and suggestions made to widen its generality.     

THE INFLUENCE OF ALCOHOL ON THE DETECTION OF LIGHT SIGNALS IN DIFFERENT PARTS OF THE VISUAL FIELD

6 subjects performed 12 times each a signal detection task lasting 40 minutes in parallel with a simple tracking task. They reported every 2nd second whether or not a signal was given in any one of 10 widely spaced locations. 0.5 or 1.0 ml alcohol/kg body weight (or no alcohol) was given 35–25 minutes prior to the task. Hit rate ( HR ) covaried with tracking efficiency; FAR was uniformly low. Variation in signal probability had no effect. Alcohol had a strong and uniform effect on 3 "experienced" subjects, reducing HR for all signals and producing a funneling effect, but had little effect on the performance of 3 "inexperienced" subjects. Motivational variables which may account for the individual differences are discussed.     

The Impact of Clients’ and Therapists’ Characteristics on Therapeutic Alliance and Outcome

Journal of Contemporary Psychotherapy - This article investigates distances between therapists and their clients in their experience of the therapeutic alliance across the duration of the...     

Sequence learning in Parkinson's disease: the effect of spatial stimulus-response compatibility

Patients with Parkinson's disease (PD) have repeatedly demonstrated reduced sequence-specific learning effects in serial reaction time tasks (SRTs). Previous research with PD patients has mainly employed the 'classical' SRT task, involving a spatially compatible assignment of stimuli and responses. From cognitive research, it is known that spatial compatibility triggers rapid, automatic responses in the direction of the stimulus. Automatic responding has shown to be disinhibited in PD patients and may therefore interfere with stimulus anticipation during the learning process. The aim of the present study was to test this hypothesis by investigating if reduced sequence-specific learning depends on spatial stimulus-response compatibility. PD patients and age-matched controls were examined either with an SRT variant involving central stimulus presentation, thereby preventing automatic linking of stimulus and response locations, or with a spatially compatible SRT task. Patients showed reduced sequence-specific learning effects only when the stimulus-response assignment was spatially compatible. This pattern of results confirms the hypothesis that sequence learning deficits in PD may result from a predominance of automatic response activation over learning-based stimulus anticipations during the learning phase.