Preschool children's eye‐movements during pictorial recall

We investigated eye‐movements during preschool children's pictorial recall of seen objects. Thirteen 3‐ to 4‐year‐old children completed a perceptual encoding and a pictorial recall task. First, they were exposed to 16 pictorial objects, which were positioned in one of four distinct areas on the computer screen. Subsequently, they had to recall these pictorial objects from memory in order to respond to specific questions about visual details. We found that children spent more time fixating the areas in which the pictorial objects were previously displayed. We conclude that as early as age 3–4 years old, children show specific eye‐movements when they recall pictorial contents of previously seen objects.     

A novel automatic procedure for measuring ocular counterrolling: A computeranalytical method to determine the eye’s roll angle while subjects work on perceptual tasks

In investigations of the perception of space, the consideration of ocular counterrolling-the movement of the eye around its visual axis in response to body movement-is crucially important. The angle of this movement must be known in order for one to determine the precise retinal coordinates of a distal object. Following transformation, this stimulus serves as a reliable cue for visual direction. The otolith organs provide information about body tilt and are responsible for ocular counterrolling. A novel, noninvasive method to measure ocular counterrolling, based on the cross-correlation of digitized video pictures of the eyes, is presented. The resolution attained was ≤ 0.1°. The computer analysis is fully automatic and fast, and it can be performed while subjects work on perceptual tasks. No direct access to the eyeballs is required. Data from 4 subjects showing the counterrolling profile in various body positions are presented.     

The prioritization of visuo-spatial associations during mental imagery

While previous research has shown that during mental imagery participants look back to areas visited during encoding it is unclear what happens when information presented during encoding is incongruent. To investigate this research question, we presented 30 participants with incongruent audio-visual associations (e.g. the image of a car paired with the sound of a cat) and later asked them to create a congruent mental representation based on the auditory cue (e.g. to create a mental representation of a cat while hearing the sound of a cat). The results revealed that participants spent more time in the areas where they previously saw the object and that incongruent audio-visual information during encoding did not appear to interfere with the generation and maintenance of mental images. This finding suggests that eye movements can be flexibly employed during mental imagery depending on the demands of the task.

     

Mental imagery of visual motion modifies the perception of roll-vection stimulation

When viewing a wide-angle visual display, which rotates in the frontoparallel plane around the line of sight, observers experience an illusory shift of the direction of gravity; this shift leads to an apparent tilt of the body and displaces allocentric space coordinates. In this study, subjects adjusted an indicator to the apparent horizontal while viewing a rotating display. To determine whether top down processes could affect the illusion, the subjects were asked to visualize a rotating configuration of dots onto a blank central portion of the moving visual field. Visualizing dots and actually viewing the dots deflected the spatial judgment in very similar ways. These results demonstrate that top down processing can affect allocentric space coordinates.     

Emergent Power Hierarchies and Group Performance

In newly formed groups, informal hierarchies emerge automatically and readily. In this study, we argue that emergent group hierarchies enhance group performance (Hypothesis 1) and we assume that the more the power hierarchy within a group corresponds to the task‐competence differences of the individual group members, the better the group performs (Hypothesis 2). Twelve three‐person groups and 28 four‐person groups were investigated while solving the Winter Survival Task. Results show that emerging power hierarchies positively impact group performance but the alignment between task‐competence and power hierarchy did not affect group performance. Thus, emergent power hierarchies are beneficial for group performance and although they were on average created around individual group members' competence, this correspondence was not a prerequisite for better group performance.     

The role of cognitive appraisal in media-induced presence and emotions

In the present study, we applied Valins’ (1966) bogus bodily feedback paradigm to investigate the roles of cognitive appraisal (tele)presence, and emotion in the context of media usage. Participants (N=30) viewed short sequences of a TV show, whereby false heart rate feedback was provided. In line with Valins’ paradigm, the manipulation we used in this study included two levels: high vs. low false heart rate feedback. We assessed presence, enjoyment, and the real heart rate. Participants reported stronger experiences of presence and enjoyed the clips more when they wrongly believed that they had been aroused. Since bogus feedback increases the sensation of presence, the results indicate that presence—like emotions—can be influenced by cognitive appraisals. It is likely that the false heart rate feedback was attributed to the stimulus, which in turn enhanced the sensation of presence.     

Room temperature ferromagnetism and photoluminescence of nanocrystalline Zn1 − xCoxO thin films prepared by sol–gel MOD

Zn_1???xCo_xO (ZC) [x?=?0, 1, 3, 5, 7 and 9?mol%] thin films were prepared by sol–gel combined metallo-organic decomposition method. The films were deposited on the Si substrate with spin-coating technique and annealed at 600?°C for 3?h. X-ray diffraction pattern shows the formation hexagonal wurtzite phase and distortion (c/a) decreases with increasing Co concentration in ZnO. The average grain size is measured using Scherer relation. Atomic force microscopy is used to confirm the formation of nanograins resulted by the use of polyethylene glycol as surfactant. The photoluminescence was recorded by using He-Cd laser of excitation wavelength 325?nm in wavelength region of 350–650?nm which exhibits some influence of Co doping on the multiplication of defects such as O vacancies, Zn interstitials and grain boundary defects. All thin films show room temperature ferromagnetism except pure ZnO which is diamagnetic and 9?mol% of Co shows paramagnetism. This behaviour is interpreted as due to fluctuations in the magnetic ordering, depending on grain size and site location in grain boundaries or oxygen vacancies.     

A MIMIC Model Approach to Research in Geriatric Neuropsychology: The Case of Vascular Dementia

The goal of the current study is to demonstrate a new methodology that can be used in neuropsychological research concerning differential diagnosis research. The multiple indicators, multiple causes (MIMIC) model is a latent variable methodology which can examine group differences on individual tests while controlling group differences in global cognitive impairment. As a demonstration, neuropsychological data from 217 dementia patients were incorporated into a MIMIC model to examine the influence of cerebrovascular disease (CVD) upon (1) dimensions of global cognitive impairment and (2) upon individual tests after controlling for global impairment. The presence of CVD in dementia (i.e., vascular dementia [VaD]) was not significantly related to dimensions of global impairment. In addition, the presence of CVD within dementia did not significantly contribute to impairment on 9 out of 10 neuropsychological tests/subscales examined after controlling global cognitive impairment. These results are discussed in the context of current vascular dementia research, and are focused primarily upon the MIMIC model methodology and suggestions for its use in future research.