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Sudden visual changes attract our gaze, and related eye movement control requires attentional resources. Attention is a limited resource that is also involved in working memory-for instance, memory encoding. As a consequence, theory suggests that gaze capture could impair the buildup of memory respresentations due to an attentional resource bottleneck. Here we developed an experimental design combining a serial memory task (verbal or spatial) and concurrent gaze capture by a distractor (of high or low similarity to the relevant item). The results cannot be explained by a general resource bottleneck. Specifically, we observed that capture by the low-similar distractor resulted in delayed and reduced saccade rates to relevant items in both memory tasks. However, while spatial memory performance decreased, verbal memory remained unaffected. In contrast, the high-similar distractor led to capture and memory loss for both tasks. Our results lend support to the view that gaze capture leads to activation of irrelevant representations in working memory that compete for selection at recall. Activation of irrelevant spatial representations distracts spatial recall, whereas activation of irrelevant verbal features impairs verbal memory performance.
The initial interview is important for psychological counseling regarding the acquisition of diagnostic information and in terms of establishing a professional counseling relationship. In applied sports psychology there so far exist no clear guidelines to structure this process. To improve the quality of sports psychological consultations, the present study introduces and evaluates a semi-structured guideline for an initial interview in which the content and form of the consultation are determined, the concerns of the client are systematically explored, and the objectives of the collaboration and the further process are defined. Eleven sport psychology trainees participated in our study and conducted initial interviews with actors. One interview was conducted by using the initial interview guide and the other interview was created individually by each sport psychology trainee based on his own expertise. The results showed that the quality of the interview process (i.e., formal requirements, use of open questions) as well as the satisfaction of the consultant with the interview was significantly higher when following the guideline. No differences were found regarding the quality of the consultation findings and the satisfaction of the athletes with the interview. The results are discussed with respect to their theoretical and practical implications.
During visual fixation on a target object, our eyes are not motionless but generate slow fixational eye movements and microsaccades. Effects of visual attention have been observed in both microsaccade rates and spatial directions. Experimental results, however, range from early (<200 ms) to late (>600 ms) effects combined with cue-congruent as well as cue-incongruent microsaccade directions. On the basis of well characterized neural circuitry in superior colliculus, we construct a dynamical model of neural activation that is modulated by perceptual input and visual attention. Our results show that additive integration of low-level perceptual responses and visual attention can explain microsaccade rate and direction effects across a range of visual cueing tasks. These findings suggest that the patterns of microsaccade direction observed in experiments are compatible with a single dynamical mechanism. The basic principles of the model are highly relevant to the general problem of integration of low-level perception and top-down selective attention.
Current models of eye movement control are derived from theories assuming serial processing of single items or from theories based on parallel processing of multiple items at a time. This issue has persisted because most investigated paradigms generated data compatible with both serial and parallel models. Here, we study eye movements in a sequential scanning task, where stimulus n indicates the position of the next stimulus n + 1. We investigate whether eye movements are controlled by sequential attention shifts when the task requires serial order of processing. Our measures of distributed processing in the form of parafoveal-on-foveal effects, long-range modulations of target selection, and skipping saccades provide evidence against models strictly based on serial attention shifts. We conclude that our results lend support to parallel processing as a strategy for eye movement control.
Bayesian selection of Markov Models for symbol sequences application to microsaccadic eye movements
(2012)
Complex biological dynamics often generate sequences of discrete events which can be described as a Markov process. The order of the underlying Markovian stochastic process is fundamental for characterizing statistical dependencies within sequences. As an example for this class of biological systems, we investigate the Markov order of sequences of microsaccadic eye movements from human observers. We calculate the integrated likelihood of a given sequence for various orders of the Markov process and use this in a Bayesian framework for statistical inference on the Markov order. Our analysis shows that data from most participants are best explained by a first-order Markov process. This is compatible with recent findings of a statistical coupling of subsequent microsaccade orientations. Our method might prove to be useful for a broad class of biological systems.
In this study we re-evaluate the estimation of the self-similarity exponent of fixational eye movements using Bayesian theory. Our analysis is based on a subsampling decomposition, which permits an analysis of the signal up to some scale factor. We demonstrate that our approach can be applied to simulated data from mathematical models of fixational eye movements to distinguish the models' properties reliably.