Vision Sciences Society Annual Meeting Abstract
The capacity of fine vision of individual object is limited by the "bottleneck" of attention and working memory. Still, at every moment we see large collections of objects. What exactly happens to individual representations when the observer attempts to distribute attention between multiple objects? One view is that a fixed number of objects are represented with good fidelity while others are represented with poor fidelity. Another theory is that attention is evenly distributed among all objects but fidelity decreases as set size grows. This debate is one in the core of a theory of summary representation of multiple objects (Alvarez, 2011; Myczek & Simons, 2008). Here we directly tested how the capacity and fidelity change with set size. Participants were briefly shown sets of 1, 2, 4, or 8 circles of various sizes. Then, one of the circles increased or decreased in size by 2- 20% (change step 2%). The change was synchronized with a global background flash masking the local transient caused by the circle change. Observers had to respond whether they had seen an increment or decrement in any of the circles (2AFC). These manipulations rely on an assumption that one needs attention to the stimulus to spot a change (Rensink et al., 1997). Psychometric functions were fit using normal cumulative density functions. We found that the set size affects the probability of correct response at which the function reaches a plateau: the larger was a set size, the lower was such probability. The standard deviations of the functions typically associated with fidelity were relatively similar across set sizes within each observer. We conclude, therefore, that, when observers perceive multiple objects during a short time, they focus attention on a limited sample of items represented with the same fidelity, rather than evenly distribute it among all the objects.
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.
The study was devoted to the investigation of the relationships between the basic characteristics of temperament, measured by different questionnaires, and parameters of the event-related potentials recorded in a classical attentional odd-ball task.
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?
It has been shown that multiple objects can be efficiently represented as ensemble summary statistics, such as the average. Recently, Kanaya et al. (2018) demonstrated the amplification effect in the perception of average. Their participants judged the mean size or temporal frequency of ensembles, and they tended to exaggerate their estimates, especially larger set sizes. Kanaya et al. explained it by non-exhaustive sampling mechanism favoring ~sqrt(N) most salient items, which are either largest or most frequently ones. But how do the rest of elements contribute to ensemble perception? In our study, we used orientation averaging (which does not have any inevitably salient values) and manipulated the salience of individual items via size. Participants had to adjust the average orientation of 4, 8, or 16 triangles. We measured systematic biases, like Kanaya et al. (2018), and SD of errors that are known to correlate with the physical ensemble range. In Experiment 1, most clockwise elements could be bigger, counterclockwise, middle, or all elements were same-size. We found strong clockwise and counterclockwise biases in the corresponding conditions. The biases increased with set size replicating Kanaya et al. (2018). But we found no SD difference between the conditions suggesting that all items were somehow taken into account. In Experiment 2, we compared distributions with same ranges (full-sets) but salient elements being middle or extreme (most clockwise and counterclockwise). We used distribution with only middle elements or only extremes as controls (half-sets). We found that SD in the full-sets were greater than in the middle half-sets and smaller than in the extreme half-sets suggesting that all items were taken into account. We also found that SD in the extreme full-sets were greater than in the middle full-sets in large set size. We conclude that both exhaustive and amplification types of sampling work in averaging.
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.
The world that we perceive and describe changes constantly. If we believe our descriptions of the world to be accurate and consistent, we must assume that the content and the structure of our individual sentences accurately and consistently reflect the world’s constantly changing nature. If so, a comprehensive production system must model the sentence generation process taking into account this basic assumption: Words, their linear arrangement, and the structures they are inserted in must somehow reflect the corresponding parameters of the observed and described event. This system must include representation of salience as one integral component resulting in interplay that involves constant, regular, and automatic mappings between elements of a visual scene, their varying salience, and the structural arrangement of the sentence constituents and the grammatical relations between them. In this interplay, perceptual input contributes initially to this mapping process by providing information for further conceptual and linguistic encoding. Importantly, this information is not processed in an unconstrained fashion; instead, it is systematically filtered, selected, and relayed based on a regular interface between the aspects of attention and their corresponding counterparts in the conceptual and linguistic structures. Bottom-up and top-down features of this interface include noticeability, importance, or relevance. As a result, linguistic output reflects the event’s conceptual organization including the attentional state of the speaker in a regular way. This mapping between attentional focus and structural choice is a part of a more complex mapping mechanism that we will refer to as Cognition-Language Interface or CLI. Specifically, this Chapter will consider theoretical and empirical knowledge about the complex interplay between the speaker’s attentional state and the structural choices they make during sentence production.
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.
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.
The general aim of this thesis is to explore the gendered and classed nature of social work and social welfare in Russia to show how social policy can be a part of and reinforce marginalisation. The overall research question is in what ways class and gender are constructed in Russian social work practice and welfare rhetoric through Soviet legacies and contemporary challenges? In addition, which actors contribute to the constitution of social work values and how this value system affects the agency of the clients? This study focuses on contradictory ideologies that are shaped in discursive formations of social policy, social work training and practice. It is a qualitative study, containing fi ve papers looking at this issue from three different perspectives: policy and institutions, culture and discourse, actors and identity. The data collection was arranged as a purposive–iterative process. The empirical material consists of qualitative interviews with social work practitioners, administrators and clients, participant observations in social services and analysis of documents of various kinds.
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.