ОСОБЕННОСТИ САККАДИЧЕСКИХ РЕАКЦИЙ НА ПОСЛЕДОВАТЕЛЬНЫЕ ЗРИТЕЛЬНЫЕ СТИМУЛЫ В НОРМЕ И ПРИ ШИЗОФРЕНИИ
We studied the features of cognitive functions of attention and decision making in 18 healthy subjects and 15 patients with schizophrenia with the use of pairs of two short visual stimuli (double step). In the group of patients with schizophrenia, we observed a higher number of errors and higher frequency of modified saccad ic pattern – two saccades to each stimulus instead of only one saccade to the second stimulus. In these pa tients, the latency period of the first saccade was shorter, while the latency period of a single saccade to the second stimulus was longer as compared with healthy subjects. The lateral differences in the saccade latency in schizophrenic and healthy subjects are opposite. The data provide an evidence of disorders in the cognitive control and prognostic processes of saccade pro gramming in schizophrenic patients.
The distractive effects on attentional task performance in different paradigms are analyzed in this paper. I demonstrate how distractors may negatively affect (interference effect), positively (redundancy effect) or neutrally (null effect). Distractor effects described in literature are classified in accordance with their hypothetical source. The general rule of the theory is also introduced. It contains the formal prediction of the particular distractor effect, based on entropy and redundancy measures from the mathematical theory of communication (Shannon, 1948). Single- vs dual-process frameworks are considered for hypothetical mechanisms which underpin the distractor effects. Distractor profiles (DPs) are also introduced for the formalization and simple visualization of experimental data concerning the distractor effects. Typical shapes of DPs and their interpretations are discussed with examples from three frequently cited experiments. Finally, the paper introduces hierarchical hypothesis that states the level-fashion modulating interrelations between distractor effects of different classes.
It is well known, that even in optimal conditions animals and humans make spontaneous errors which are the most prominent manifestations of attention system failures. Our goal was to investigate the causes of attention system failures in normal state of arousal and without distracting objects. We have designed a new task which allows to answer the following question: which stage of sensory processing is compromised during attention lapses?
The article proposes application of the level approach to attention research. Four basic principles of levelbased architecture of attention are derived from theoretical premises of the level approach to cognition and the psychology of attention as well as from empirical data. The author offers a variant of empirical research program which is based on the logic of the level approach. Finally the 5 level model of attention processes organization is proposed on the basis on experimental data. The article also contains examples of author's empirical studies which are interpreted in the level approach framework. The first study demonstrates the functioning of the redundancy principle (which is one the basic principles stated in study) in the visual inspection tasks. The second study shows the differences in the efficiency of memorizing the same material and the differences in experiencing of subjective confidence in mnemonic judgments depending on the leading level of attention in task solving.
Distractor's effect (stimulus which is irrelevant at a certain moment and ignored) on task solving efficiency is considered. It is revealed that according to problem situation and connection with target stimulus any distractor can produce two opposite effects: negative - interference and positive - redundancy effect. Distractor effects' classification based on one of possible grounds - distractor's source: sensory inputs effects, hierarchical effects and correlational effects is given. Possibility of level-hierarchical relation between the three classes of effects is discussed.
The article examines ways of describing human experience and behavior from the first, the second and the third-person perspectives and their applicability for people with schizophrenia. It is quite difficult to describe the experience of such people from the third-person perspective, hence there is a great need in address to other methods and paying attention at prospects connected with them. Moreover, the article presents the changeability of conceptual framework depending on whose experience and behavior we investigate.
Tonic brain activity has significant influences on the nature of a subject’s responses to target sensory stimuli. We report here studies of the dynamics of the background activity in the gamma-rhythm range of the EEG in rabbits during execution of an “active oddball” paradigm modified for animals – a task widely used for studies of attention. Increased levels of power and coherence in background gamma activity were found to reflect expectation of a target stimulus, correct responses to stimuli being executed at a particular level of background gamma activity which probably corresponds to the optimum level of sustained (tonic) attention. Decreases in the level of gamma activity led to missed responses to the target stimulus, while excess levels lead to erroneous responses to non-target signals (false anxiety). These dynamics of background gamma activity are interpreted as resulting from oscillations in the level of tonic cholinergic activation of right cerebral cortex.
This article describes the expierence of studying factors influencing the social well-being of educational migrants as mesured by means of a psychological well-being scale (A. Perrudet-Badoux, G.A. Mendelsohn, J.Chiche, 1988) previously adapted for Russian by M.V. Sokolova. A statistical analysis of the scale's reliability is performed. Trends in dynamics of subjective well-being are indentified on the basis the correlations analysis between the condbtbions of adaptation and its success rate, and potential mechanisms for developing subjective well-being among student migrants living in student hostels are described. Particular attention is paid to commuting as a factor of adaptation.