Cognitive style of field dependence-independence modulates the working memory storage of biological motion.

The biological motion refers to the continuous configuration movement of live agents in space. The perceptual processing of biological motion has the specificity of the dissociation between body form and body motion. However, there is limited evidence for whether such specificity continues when holding biological motion in working memory. We explored this question from the perspective of field dependence (FD) and field independence (FI) cognitive styles in the current study. Three categories of biological motion have been developed: intact movement, motion feature, and form feature. We examined the working memory capacity of motion features, form features, intact movements (Experiments 1-3), and the recognition of three categories of biological motion when remembering intact movements (Experiment 4). The results showed that for the motion features, FI individuals had better memory performance when remembering five items and showed greater working memory capacity and recognition compared with FD individuals, whereas the opposite pattern was observed between FI and FD individuals for the form features. The cognitive style could modulate the working memory storage of biological motion when the task becomes demanding, suggesting that body form and body motion are dissociable in working memory. Our study provided additional evidence for the specificity of biological motion processing in working memory, extending the hierarchical neural model. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A Punctuated Equilibrium Model for Conceptual Change and the Role of Neo-Piagetian Constructs: Methodology, Empirical Evidence, and Theoretical Perspectives.

This study explores the hypothesis related to a punctuated equilibrium process for conceptual change in science learning, in conjunction with the effects of four cognitive variables: logical thinking and field-dependence/field-independence, divergent and convergent thinking. The participants were fifth and sixth-grade elementary school pupils involved in different tasks, who were asked to describe and interpret chemical phenomena. Latent Class Analysis (LCA) was applied to children's responses, and three clusters or latent classes (LC1, LC2, and LC3) were identified, corresponding to hierarchical levels of conceptual understanding. The ensued LCs align with the theoretical conjecture about a stepwise conceptual change process that might go through various stages or mental models. These levels or stages are conceptualized as attractors, and changes between them were modeled as cusp catastrophes using the four cognitive variables as controls. The analysis showed that logical thinking acted as asymmetry factor, while field-dependence/field-independence, divergent and convergent thinking acted as bifurcation variables. This analytic approach presents a methodology for investigating conceptual change as a punctuated equilibrium process that adds to the nonlinear dynamical research with important implications for theories of conceptual change in science education and psychology as well. Discussion on the new perspective embracing the meta-theoretical framework of complex adaptive systems (CDS) is provided.

Influência dos cuidados de enfermagem de reabilitação na recuperação da independência funcional do paciente / Influence of rehabilitation nursing care on the recovery of functional independence of the patient / Influencia de los cuidados de rehabilitación em enfermeira em la independencia funcional del paciente

Objetivo: conhecer a influência dos cuidados de enfermagem de reabilitação na recuperação da independência funcional do paciente. Método: estudo descritivocorrelacional, quantitativo, transversal e com amostragem não probabilística de tipologia acidental. Critérios de inclusão: medida independência funcional ≤90 e doentes sujeitos à imobilidade. Critérios de exclusão: portadores de doenças neoplásicas e com alterações do estado de consciência. Para a coleta de dados foi utilizado questionário sóciodemografico e a Escala MIF. Resultados: os dados da amostra (n=40), revelam uma média de idades de 76,4 anos, na sua maioria mulheres (57,5%), casadas (55%), com o primeiro ciclo de escolaridade (70%), e estiveram sujeitos em média a 49,6 dias de imobilidade. A independência funcional teve uma melhoria significativa da 1ª (46,69) para a 2ª avaliação (94,61). Conclusão: a imobilidade tende a prejudicar a qualidade de vida e saúde da pessoa, exigindo intervenção profissional. Essas pessoas sob cuidados de enfermeiros de reabilitação, recuperaram 36,98% da sua independência funcional.

Objective: to know the influence of rehabilitation nursing care on the recovery of functional independence of the patient. Method: descriptive-correlational, quantitative, cross-sectional study with non-probability sampling of accidental typology. Inclusion criteria: functional independence measure ≤90 and patients subject to immobility. Exclusion criteria: patients with neoplastic diseases and altered state of consciousness. For data collection, a sociodemographic questionnaire and the MIF Scale were used. Results: The sample data (n = 40) reveal an average age of 76.4 years, mostly women (57.5%), married (55%),with the first level of education (70%), and were subject to 49.6 days of immobility on average. Functional independence improved significantly from the 1 st (46.69) to the 2 nd assessment (94.61). Conclusion: immobility tends to impair the person's quality of life and health, requiring professional intervention. These people under the care of rehabilitation nurses, recovered 36.98% of their functional independence.

Objetivo: conocer la influencia de los cuidados de rehabilitación en enfermería en la recuperación de la independencia funcional de pacientes sujetos a inmovilidad. Método: estudio descriptivo-correlacional, cuantitativo, transversal y muestreo no probabilístico de tipología accidental en pacientes sometidos a inmovilidad. Criterios de inclusión: Medida de Independencia Funcional (MIF) ≤90 y pacientes sujetos a inmovilidad. Criterios de exclusión: pacientes con enfermedades neoplásicas y estado alterado de conciencia. Para la recolección de datos, se utilizó un cuestionario sociodemográfico y la Escala MIF. Resultados: los datos de la muestra (n = 40) revelan una edad promedio de 76,48 años, en su mayoría mujeres (57,5%), casadas (55%), 70% con el primer ciclo de educación, y estaban en promedio sujetos a 49,60 días de inmovilidad. La independencia funcional mejoró significativamente de la primera (46,69) a la segunda evaluación (94,61). Conclusión: la inmovilidad tiende a prejudicar la calidade de vida y salud de la persona, lo que requiere intervención profisional. Estas personas bajo el cuidado de enfermeras de rehabilitación recuperaron el 36,98% de su independencia funcional.

Field dependence-independence differently affects retrospective time estimation and flicker-induced time dilation.

Field dependence-independence (FDI) is a stable dimension of individual functioning, transversal to different cognitive domains. While the role of some individual variables in time perception has received considerable attention, it is not clear whether and how FDI influences timing abilities. In this study, we tested the hypothesis that FDI differently affects timing performance depending on whether the task requires cognitive restructuring. Participants were assessed for FDI using the embedded figures test (EFT). They performed a prospective timing task, reproducing the duration of a flickering stimulus, and a retrospective timing task, estimating the duration of the task. We expected performance of field-dependent (FD) and field-independent (FI) individuals not to differ in the prospective task, since restructuring of task material is not needed to reproduce the stimulus duration. Conversely, we predicted that FI individuals should be more accurate than FD ones in the retrospective condition, involving restructuring skills. Results show that while both FD and FI individuals under-reproduced the stimulus duration in the prospective task, only FD participants significantly underestimated the duration of the timing task in the retrospective condition. These results suggest that differences across FD and FI individuals are apparent in timing only when the task requires high-level cognitive processing; conversely, these differences do not affect basic sensory processing.

Unexpected conflict signals loom larger in a positive context: Evidence from context specific control adjustments.

One prominent feature of adaptive cognition in humans is the ability to flexibly adjust to changing task demands. In this respect, context-specific proportion congruency (CSPC) effects describe the phenomenon that participants learn to adapt to contexts of frequently occurring conflicts even when the upcoming context cannot be anticipated. Here, we aim to provide evidence that such CSPC effects strongly depend on the affective valence of the context. Participants had to categorize pictures as animals versus humans (Experiment 1), words as male versus female (Experiment 2), and food pictures as depicting cold or hot dishes/beverages (Experiment 3). Stimuli were laterally presented to the left or right, creating Simon-like response interference. Half of the stimuli were of positive valence, half of negative valence with valence always being task-irrelevant. Positive or negative stimuli were associated with a high proportion of incongruent trials and a low proportion of congruent trials, respectively. In all three experiments, a CSPC effect was only significant when the high proportion of incongruent trials was associated with positive stimuli but reduced or even absent when the high proportion of incongruent trials was associated with negative stimuli. The findings further speak to the idea that it is the aversive nature of conflict stimuli that functions as a trigger for control adaptation. And such an unexpected aversive conflict signal looms larger when presented in a positive context than in a negative context. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effect of Cognitive Style on Topographical Learning Across Life Span: Insights From Normal Development.

Notwithstanding its well-established role on high-demanding spatial navigation tasks during adulthood, the effect of field dependence-independence during the acquisition of spatial navigation skills is almost unknown. This study assessed for the first time the effect of field dependence-independence on topographical learning (TL) across the life span: 195 individuals, including 54 healthy young-adults (age-range = 20-30), 46 teenagers (age-range = 11-14), and 95 children (age-range = 6-9) participated in this study. Field dependence-independence interacted with age in predicting TL. Also during childhood higher field independence was associated with better performances but not later in the life, that is, during adolescence and adulthood. This result suggests that field dependence-independence may have a role in fostering the acquisition of TL.

Funcionalidad de los adultos mayores de los Centros Vida de Villavicencio ­ Colombia / Functional ability of elders in Life Centers in Villavicencio ­ Colombia / Funcionalidade dos idosos dos Centros Vida de Villavicencia-Colômbia

Objetivo: Caracterizar las condiciones sociales, demográficas y la funcionalidad de los adultos mayores de los Centros Vida (CV) de la ciudad de Villavicencio. Materiales y métodos: Estudio descriptivo, cuantitativo, muestreo no probabilístico discrecional, donde se obtuvo un n=635; los instrumentos usados fueron la escala de Barthel y el instrumento de Lawton y Brody. Para identificar las variables sociodemográficas, el instrumento fue elaborado por las autoras. El procesamiento y análisis se realizó en el programa SPSS® versión 20. Resultados: El 47,4 % son hombres y el 52,6 % son mujeres con edades entre los 60 y 100 años, con una edad mediana de 73 años. Respecto a la valoración de las actividades básicas de la vida diaria, el 59,4 % de los adultos mayores son independientes. Por otro lado, para las actividades instrumentadas de la vida diaria, se tiene que el 67,6 % de los adultos mayores presenta una valoración de independiente. Conclusión: Los adultos mayores adscritos a los Centros Vida de la ciudad de Villavicencio son, en general, adultos mayores funcionales; sin embargo, existe un grupo importante con factores de riesgo, lo que indica que se deben implementar estrategias de prevención de dependencia y promoción de envejecimiento exitoso.

Objective: Characterize the social and demographic conditions, and the functional ability of elders in Life Centers (LC) in the city of Villavicencio. Materials and methods: Quantitative and descriptive study, non-probabilistic discrete sampling with n=635; the instruments used were the Barthel scale and the Lawton and Brody Instrumental Activities of Daily Living scale (IADL). To identify the sociodemographic variables, an instrument was elaborated by the authors. The processing and analysis was made using SPSS Statistics® 20. Results: In the study, 47.4% were men and 52.6% were women in the age range between 60 and 100 years, with a median age of 73 years. Regarding the evaluation of basic daily activities, 59.4% of the elders are independent. On the other hand, for instrumental activities of daily living, 67.6% of elders are independent. Conclusion: Elders from the Life Centers in the city of Villavicencio are, generally, functional elders; however, there is an important group with risk factors, which indicates that prevention of dependency and promotion of successful aging strategies should be implemented.

Objetivo: Caracterizar as condições sociais, demográficas e a funcionalidade dos idosos dos Centros Vida (CV) da cidade de Villavicencio. Materiais e métodos: Estudo descritivo, quantitativo, amostragem não probabilística discricional, onde se obteve um n=635; os instrumentos empregados foram a escala de Barthel e a escala de Lawton & Brody. Para identificar as variáveis sociais e demográficas empregou-se um instrumento elaborado pelas pesquisadoras. O processamento e a análise dos dados realizou-se empregando o programa SPSS® versão 20. Resultados: 0 47,4 % foram homens e o 52,6 % mulheres com idades entre os 60 e 100 anos, com uma mediana de idade de 73 anos. Na avaliação das atividades básicas do dia a dia, o 59,4 % dos idosos eram independentes. Do mesmo modo, para realizar as atividades instrumentadas do dia a dia, observou-se que o 67,6% dos idosos são independentes. Conclusão: Os idosos acompanhados nos Centros Vida da cidade de Villavencio são, geralmente, idosos funcionais, entretanto, existe um grupo importante com fatores de risco, o que indica que devem-se implementar estratégias de prevenção de dependência e promoção de envelhecimento exitoso.

Age-Related Changes in Field Dependence-Independence and Implications for Geriatric Rehabilitation: A Review.

Human aging is a dynamic life-long process and an inevitable experience. As the average age of the world's population rises, demands for effective geriatric rehabilitation dramatically increase. An important consideration for enhancing geriatric behavioral interventions is to better understand aging characteristics in perceptual, cognitive, and motor performances. A general shift in cognitive style from field independence to field dependence has been consistently observed during human aging, as older adults show a greater tendency to rely on environmental information, presumably reflecting a neuro-compensatory mechanism of reducing top-down control and relying instead on bottom-up processing. These changes in cognitive style can impact motor skill learning and relearning and, consequently, affect geriatric rehabilitation and behavioral treatments. In this article, we review research related to the cognitive style of field dependence and independence, and its dynamic associations with aging. We also identify implications of cognitive style for geriatric rehabilitation and explore future research.

Figure-Ground Processing: A Reassessment of Gelb and Granit.

In 1923, Adhemar Gelb and Ragnar Granit, two prominent researchers in early Gestalt perceptual theory, reported a lower threshold for detection of a target (a small colored dot) on the ground region of an image than on an adjacent figural region. Although their results had a wide influence on the understanding of figure-ground perception, they are at odds with more recent investigations in which figural regions appear to have a processing advantage over ground regions. The two present studies replicated Gelb and Granit's experiment using a similar figure-ground stimulus albeit with a two-alternative forced choice procedure rather than their original method of adjustment. Experiment 1 found that, contrary to Gelb and Granit's findings, a detection advantage was found for the figural over the ground region. Experiment 2 indicated that explicit contours might have played a role in detection.

Acerca de la transferencia delirante (transferencia psicótica) / On delusional transference (transference psychosis) / A propos du transfert délirant (transfert psychotique)

En la primera parte del artículo, Margaret Little parte de las dificultades técnicas que plantean las interpretaciones tranferenciales en determinados pacientes, que no responden a un grupo definido, y que la llevan a interrogarse sobre el tipo de transferencia que desarrollan. La ausencia de la cualidad «como sí» en este tipo de transferencia lleva a la autora a una reevaluación de la comprensión y de la técnica de dichos tratamientos. En la segunda parte del artículo, M. Little se esfuerza por insertar sus reflexiones clínicas en el marco del pensamiento psicoanalítico de entonces. Propone pensar ciertos fenómenos a partir de su concepto de «unidad básica del ser» como un estado primordial de indiferenciación

In the first part of the paper, Little outlines the technical difficulties raised by transference interpretations in certain patients, who do not fit within a clearly defined group, which prompts her to question the type of transference developed by these patients. The absence of the "as if" quality in this type of transference leads the author to re-evaluate both our understanding of, and technical approach to, these treatments. In the second part of the article, Little endeavours to insert her clinical reflections within the context of psychoanalytic thought of the time. She postulates that certain phenomena be considered in reference to her concept of "basic unit of being" as a primal state of undifferentiation

Dans la première partie de l'article M. Little part des difficultés techniques posées par les interprétations transférentielles chez certains patients qui ne correspondent pas a un groupe défini et qui la mènent à s'interroger sur le type de transfert qu'ils développent. La carence d'une qualité «Comme si» dans ce type de transfert amene l'auteure a une réévaluation de la compréhension et de la technique de ces traitements. Dans la seconde partie de l'article M. Little essaye s'insérer ses réflexions cliniques dans le cadre de la pensée psychanalytique de son temps. Ell propose de réfléchir à certains phénomènes a partit de son concept «d'unité basique de l'être» comme un etat primordial d'indifférentiation

Texture density adaptation can be bidirectional.

Texture density has previously been thought of as a scalar attribute on the assumption that texture density adaptation only reduces, not enhances, perceived density (Durgin & Huk, 1997). This "unidirectional" property of density adaptation is in contradistinction to the finding that simultaneous density contrast (SDC) is "bidirectional"; that is, not only do denser surrounds reduce the perceived density of a lower density region, but sparser surrounds enhance it (Sun, Baker, & Kingdom, 2016). Here we reexamine the directionality of density adaptation using random dot patterns and a two-alternative forced choice task in which observers compare the perceived density of adapted test patches with unadapted match stimuli. In the first experiment, we observed a unidirectional density aftereffect when test and match were presented simultaneously as in previous studies. However, when they were presented sequentially, bidirectionality was obtained. This bidirectional aftereffect remained when the presentation order of test and match was reversed (second experiment). In the third experiment, we used sequential presentation to measure the density aftereffect for a wide range of adaptor densities (0-73 dots/deg2) and test densities (1.6, 6.4, and 25.6 dots/deg2). We found bidirectionality for all combinations of adaptor and test densities, consistent with our previous SDC results. This evidence supports the idea that there are multiple channels selective to texture density in human vision.

The relationship between cognitive style and event-related potentials during auditory and somatosensory Go/No-go paradigms.

Cognitive style including field dependence/independence (FDI) is an important factor affecting individual personalities. The present study aimed to clarify the relationship between cognitive styles and the characteristics of cognitive processing using event-related potentials. We used the Embedded-Figures Test to assess the cognitive styles [field dependence (FD), field independence (FI)] of the individuals, and individuals performed auditory and somatosensory Go/No-go paradigms. Participants were divided into two groups (FD and FI) on the basis of EFT scores. Reaction times during auditory Go/No-go paradigms were significantly earlier in the FI group than in the FD group, and response variabilities and omission errors were significantly smaller in the FI group than in the FD group. Go-P300 and No-go-P300 amplitudes were significantly larger in the FI group than in the FD group, suggesting that the FI group exhibited greater neural activity for response executive and inhibitory processing. No significant differences were observed in the amplitudes or latencies of auditory N100 and somatosensory N140 components between the FI and FD groups, suggesting that auditory-related and somatosensory-related neural activities were not related to FDI cognitive styles. Our results showed that FDI cognitive styles were related to neural activity for response executive and inhibitory processing.

The effect of letter string length and report condition on letter recognition accuracy.

PURPOSE: Letter sequence recognition accuracy has been postulated to be limited primarily by low-level visual factors. The influence of high level factors such as visual memory (load and decay) has been largely overlooked. This study provides insight into the role of these factors by investigating the interaction between letter sequence recognition accuracy, letter string length and report condition. METHODS: Letter sequence recognition accuracy for trigrams and pentagrams were measured in 10 adult subjects for two report conditions. In the complete report condition subjects reported all 3 or all 5 letters comprising trigrams and pentagrams, respectively. In the partial report condition, subjects reported only a single letter in the trigram or pentagram. Letters were presented for 100ms and rendered in high contrast, using black lowercase Courier font that subtended 0.4° at the fixation distance of 0.57m. RESULTS: Letter sequence recognition accuracy was consistently higher for trigrams compared to pentagrams especially for letter positions away from fixation. While partial report increased recognition accuracy in both string length conditions, the effect was larger for pentagrams, and most evident for the final letter positions within trigrams and pentagrams. The effect of partial report on recognition accuracy for the final letter positions increased as eccentricity increased away from fixation, and was independent of the inner/outer position of a letter. CONCLUSIONS: Higher-level visual memory functions (memory load and decay) play a role in letter sequence recognition accuracy. There is also suggestion of additional delays imposed on memory encoding by crowded letter elements.

Effects of aging on figure-ground perception: Convexity context effects and competition resolution.

We examined age-related differences in figure-ground perception by exploring the effect of age on Convexity Context Effects (CCE; Peterson & Salvagio, 2008). Experiment 1, using Peterson and Salvagio's procedure and black and white stimuli consisting of 2 to 8 alternating concave and convex regions, established that older adults exhibited reduced CCEs compared to younger adults. Experiments 2 and 3 demonstrated that this age difference was found at various stimulus durations and sizes. Experiment 4 compared CCEs obtained with achromatic stimuli, in which the alternating convex and concave regions were each all black or all white, and chromatic stimuli in which the concave regions were homogeneous in color but the convex regions varied in color. We found that the difference between CCEs measured with achromatic and colored stimuli was larger in older than in younger adults. Our results are consistent with the hypothesis that the senescent visual system is less able to resolve the competition among various perceptual interpretations of the figure-ground relations among stimulus regions.

Dynamic adjustments of attentional control in healthy aging.

In standard attentional control tasks, interference effects are reduced following incongruent trials compared to congruent trials, a phenomenon known as the congruency sequence effect (CSE). Typical explanations of this effect suggest the CSE is due to changes in levels of control across adjacent trials. This interpretation has been questioned by the finding that older adults, individuals with impaired attentional control systems, have been shown to produce larger CSEs in the Stroop task compared with younger adult controls. In 2 experiments, we investigate the generality of this finding by examining how the CSE changes in healthy aging in 3 standard attentional control tasks-Stroop, Simon, and flanker-while controlling for additional confounds that have plagued some of the past literature. In both experiments, older adult participants exhibited a larger CSE in the Stroop task, replicating recent research, but smaller CSEs in both the Simon and flanker paradigms. These results are interpreted as reflecting a pathway priming mechanism in the Stroop task but a control adjustment process in Simon and flanker. Hence, there appears to be different mechanisms underlying the CSE which are engaged based on the type of attentional selection that is required by the task. More generally, these results question the use of the CSE in the Stroop task as a measure of dynamic adjustments in attentional control and highlight the importance of consideration of task-specific control systems underlying the CSE. (PsycINFO Database Record

Statistical learning of parts and wholes: A neural network approach.

Statistical learning is often considered to be a means of discovering the units of perception, such as words and objects, and representing them as explicit "chunks." However, entities are not undifferentiated wholes but often contain parts that contribute systematically to their meanings. Studies of incidental auditory or visual statistical learning suggest that, as participants learn about wholes they become insensitive to parts embedded within them, but this seems difficult to reconcile with a broad range of findings in which parts and wholes work together to contribute to behavior. Bayesian approaches provide a principled description of how parts and wholes can contribute simultaneously to performance, but are generally not intended to model the computations that actually give rise to this performance. In the current work, we develop an account based on learning in artificial neural networks in which the representation of parts and wholes is a matter of degree, and the extent to which they cooperate or compete arises naturally through incidental learning. We show that the approach accounts for a wide range of findings concerning the relationship between parts and wholes in auditory and visual statistical learning, including some findings previously thought to be problematic for neural network approaches. (PsycINFO Database Record

Top-down knowledge modulates onset capture in a feedforward manner.

How do we select behaviourally important information from cluttered visual environments? Previous research has shown that both top-down, goal-driven factors and bottom-up, stimulus-driven factors determine which stimuli are selected. However, it is still debated when top-down processes modulate visual selection. According to a feedforward account, top-down processes modulate visual processing even before the appearance of any stimuli, whereas others claim that top-down processes modulate visual selection only at a late stage, via feedback processing. In line with such a dual stage account, some studies found that eye movements to an irrelevant onset distractor are not modulated by its similarity to the target stimulus, especially when eye movements are launched early (within 150-ms post stimulus onset). However, in these studies the target transiently changed colour due to a colour after-effect that occurred during premasking, and the time course analyses were incomplete. The present study tested the feedforward account against the dual stage account in two eye tracking experiments, with and without colour after-effects (Exp. 1), as well when the target colour varied randomly and observers were informed of the target colour with a word cue (Exp. 2). The results showed that top-down processes modulated the earliest eye movements to the onset distractors (<150-ms latencies), without incurring any costs for selection of target matching distractors. These results unambiguously support a feedforward account of top-down modulation.

Fixation durations in scene viewing: Modeling the effects of local image features, oculomotor parameters, and task.

Scene perception requires the orchestration of image- and task-related processes with oculomotor constraints. The present study was designed to investigate how these factors influence how long the eyes remain fixated on a given location. Linear mixed models (LMMs) were used to test whether local image statistics (including luminance, luminance contrast, edge density, visual clutter, and the number of homogeneous segments), calculated for 1° circular regions around fixation locations, modulate fixation durations, and how these effects depend on task-related control. Fixation durations and locations were recorded from 72 participants, each viewing 135 scenes under three different viewing instructions (memorization, preference judgment, and search). Along with the image-related predictors, the LMMs simultaneously considered a number of oculomotor and spatiotemporal covariates, including the amplitudes of the previous and next saccades, and viewing time. As a key finding, the local image features around the current fixation predicted this fixation's duration. For instance, greater luminance was associated with shorter fixation durations. Such immediacy effects were found for all three viewing tasks. Moreover, in the memorization and preference tasks, some evidence for successor effects emerged, such that some image characteristics of the upcoming location influenced how long the eyes stayed at the current location. In contrast, in the search task, scene processing was not distributed across fixation durations within the visual span. The LMM-based framework of analysis, applied to the control of fixation durations in scenes, suggests important constraints for models of scene perception and search, and for visual attention in general.

Setting and changing feature priorities in visual short-term memory.

Many everyday tasks require prioritizing some visual features over competing ones, both during the selection from the rich sensory input and while maintaining information in visual short-term memory (VSTM). Here, we show that observers can change priorities in VSTM when, initially, they attended to a different feature. Observers reported from memory the orientation of one of two spatially interspersed groups of black and white gratings. Using colored pre-cues (presented before stimulus onset) and retro-cues (presented after stimulus offset) predicting the to-be-reported group, we manipulated observers' feature priorities independently during stimulus encoding and maintenance, respectively. Valid pre-cues reliably increased observers' performance (reduced guessing, increased report precision) as compared to neutral ones; invalid pre-cues had the opposite effect. Valid retro-cues also consistently improved performance (by reducing random guesses), even if the unexpected group suddenly became relevant (invalid-valid condition). Thus, feature-based attention can reshape priorities in VSTM protecting information that would otherwise be forgotten.

Top-down and bottom-up competition in visual stimuli processing.

Limited attention capacity results that not all the stimuli present in the visual field are equally processed. While processing of salient stimuli is automatically boosted by bottom­up attention, processing of task­relevant stimuli can be boosted volitionally by top­down attention. Usually, both top­down and bottom­up influences are present simultaneously, which creates a competition between these two types of attention. We examined this competition using both behavioral and electrophysiological measures. Participants responded to letters superimposed on background pictures. We assumed that responding to different conditions of the letter task engages top­down attention to different extent, whereas processing of background pictures of varying salience engages bottom­up attention to different extent. To check how manipulation of top­down attention influences bottom­up processing, we measured evoked response potentials (ERPs) in response to pictures (engaging mostly bottom­up attention) during three conditions of a letter task (different levels of top­down engagement). Conversely, to check how manipulation of bottom­up attention influences top­down processing, we measured ERP responses for letters (engaging mostly top­down attention) while manipulating the salience of background pictures (different levels of bottom­up engagement). The correctness and reaction times in response to letters were also analyzed. As expected, most of the ERPs and behavioral measures revealed a trade­off between both types of processing: a decrease of bottom­up processing was associated with an increase of top­down processing and, similarly, a decrease of top­down processing was associated with an increase in bottom­up processing. Results proved competition between the two types of attentions.