Visual attention in change blindness for objects and shadows.

Studies have found that observers pay less attention to cast shadows in images than to better illuminated regions. In line with such observations, a recent study has suggested stronger change blindness for shadows than for objects (Ehinger et al., 2016). We here examine the role of (overt) visual attention in these findings by recording participants' eye movements. Participants first viewed all original images (without changes). They then performed a change detection task on a subset of the images with changes in objects or shadows. During both tasks, their eye movements were recorded. In line with the original study, objects (subject to change in the change detection task) were fixated more often than shadows. In contrast to the previous study, better change detection was found for shadows than for objects. The improved change detection for shadows may be explained by the balancing of trials with object and shadow changes in the present study. Eye movements during change detection indicated that participants searched the bottom half of the images. Shadows were more often present in this region, which may explain why they were easier to find.

Disaster preparedness and cultural factors: a comparative study in Romania and Malta.

This exploratory study investigates the relationships between the disaster preparedness of citizens and cultural factors in Romania and Malta. With regard to methodology, quantitative and qualitative data were collected during two Citizen Summits, which consisted of a real-time survey and focus group discussions. The results point to two specific cultural factors that may bridge this 'gap' and be operationalised to enhance people's readiness for a disaster event. In Malta, the findings reveal how community cohesion is altered from a personal to a cultural value, which has the potential to encourage the transformation of preparedness intentions into actual preparedness behaviour. In Romania, meanwhile, the findings highlight the ambivalent aspects of trusting behaviour as a cultural norm on the one hand, and distrust in authorities based on experience and unmet expectations on the other hand. Social media use may reduce this tension between trust and distrust, and thus foster successful disaster risk-related communication.

Universal Patterns in Color-Emotion Associations Are Further Shaped by Linguistic and Geographic Proximity.

Many of us "see red," "feel blue," or "turn green with envy." Are such color-emotion associations fundamental to our shared cognitive architecture, or are they cultural creations learned through our languages and traditions? To answer these questions, we tested emotional associations of colors in 4,598 participants from 30 nations speaking 22 native languages. Participants associated 20 emotion concepts with 12 color terms. Pattern-similarity analyses revealed universal color-emotion associations (average similarity coefficient r = .88). However, local differences were also apparent. A machine-learning algorithm revealed that nation predicted color-emotion associations above and beyond those observed universally. Similarity was greater when nations were linguistically or geographically close. This study highlights robust universal color-emotion associations, further modulated by linguistic and geographic factors. These results pose further theoretical and empirical questions about the affective properties of color and may inform practice in applied domains, such as well-being and design.

Developing a model of perceptions of security and insecurity in the context of crime.

The current study was carried out as part of the CITYCOP project exploring fear of crime, risk perception and feelings of security and insecurity. Participants (n = 272) from 11 European countries answered a questionnaire exploring measures of risk perception, fear of crime, anxiety, trust in police and related behaviours. A seven-factor structure is proposed incorporating 'Signs of Social and Physical Disorder', 'Trust in Police', 'Trait Anxiety', 'Collective Efficacy', 'Perceived Risk of Victimisation', 'Fear of Personal Harm' and 'Fear of Property Theft'. Overall findings suggest that the measures associated with feelings of insecurity are negatively related to the measures associated with feelings of security. Efforts should be made to reduce feelings of insecurity through encouraging trust in law enforcement and community interaction and reducing signs of social and physical disorder.

Lightness perception for surfaces moving through different illumination levels.

Lightness perception has mainly been studied with static scenes so far. This study presents four experiments investigating lightness perception under dynamic illumination conditions. We asked participants for lightness matches of a virtual three-dimensional target moving through a light field while their eye movements were recorded. We found that the target appeared differently, depending on the direction of motion in the light field and its precise position in the light field. Lightness was also strongly affected by the choice of fixation positions with the spatiotemporal image sequence. Overall, lightness constancy was improved when observers could freely view the object, over when they were forced to fixate certain regions. Our results show that dynamic scenes and nonuniform light fields are particularly challenging for our visual system. Eye movements in such scenarios are chosen to improve lightness constancy.

Contingent capture by color is sensitive to categorical color perception.

Contingent capture (CC) theory postulates that attention can only be captured by top-down matching stimuli. Although the contingent capture of attention is a well-known and thoroughly studied phenomenon, there is still no consensus on the characteristics of the top-down template which guides the search for colors. We tried to replicate the classical contingent capture effect on color (Experiment 1) and then added linguistic processing to this perceptual effect (Experiment 2). In Experiment 1, attention was indeed captured by the cues of the same color as the target, while the cues of different colors were successfully ignored. In Experiment 2, the cue color was never identical to the target color but would either belong to the same linguistic category or not (i.e., linguistic matching and linguistic nonmatching cues). In both cases, cues were made to be equally perceptually distant from the target. Although, attention was captured by both cue types, the degree of capture was significantly higher for linguistic matching cues. Our research replicated the classic contingent capture effect but on color, and also demonstrated the effect of color categories in the search task. In short, we demonstrated the effect of color categories in the search task. Results show that the template for color search contains physical characteristics of color, as well as information about color category names.

The inner tube effect.

We describe a novel size illusion in which targets appear to either shrink or grow when enclosed within a narrow tube. The direction of size change is determined by the contrast step between display elements. We first noticed this effect in the context of the dynamic "rocking line" illusion (RLI), but it can also be easily seen in completely static displays. As with the RLI, the overall scale of the display seems to play an important role. We provide an online, interactive demo, enabling the reader to explore the relevant parameter space.

Empirical evaluation of computational models of lightness perception.

Lightness of a surface depends not only on its physical characteristics, but also on the properties of the surrounding context. As a result, varying the context can significantly alter surface lightness, an effect exploited in many lightness illusions. Computational models can produce outcomes similar to human illusory percepts, allowing for demonstrable assessment of the applied mechanisms and principles. We tested 8 computational models on 13 typical displays used in lightness research (11 Illusions and 2 Mondrians), and compared them with results from human participants (N = 85). Results show that HighPass and MIR models predict empirical results for simultaneous lightness contrast (SLC) and its close variations. ODOG and its newer variants (ODOG-2 and L-ODOG) in addition to SLC displays were able to predict effect of White's illusion. RETINEX was able to predict effects of both SLC displays and Dungeon illusion. Dynamic decorrelation model was able to predict obtained effects for all tested stimuli except two SLC variations. Finally, FL-ODOG model was best at simulating human data, as it was able to predict empirical results for all displays, bar the Reversed contrast illusion. Finally, most models underperform on the Mondrian displays that represent most natural stimuli for the human visual system.

The Predation Game: Does dividing attention affect patterns of human foraging?

Attention is known to play an important role in shaping the behaviour of both human and animal foragers. Here, in three experiments, we built on previous interactive tasks to create an online foraging game for studying divided attention in human participants exposed to the (simulated) risk of predation. Participants used a "sheep" icon to collect items from different target categories randomly distributed across the display. Each trial also contained "wolf" objects, whose movement was inspired by classic studies of multiple object tracking. When participants needed to physically avoid the wolves, foraging patterns changed, with an increased tendency to switch between target categories and a decreased ability to prioritise high reward targets, relative to participants who could safely ignore them. However, when the wolves became dangerous by periodically changing form (briefly having big eyes) instead of by approaching the sheep, foraging patterns were unaffected. Spatial disruption caused by the need to rapidly shift position-rather the cost of reallocating attention-therefore appears to influence foraging in this context. These results thus confirm that participants can efficiently alternate between target selection and tracking moving objects, replicating earlier single-target search findings. Future studies may need to increase the perceived risk or potential costs associated with simulated danger, in order to elicit the extended run behaviour predicted by animal models of foraging, but absent in the current data.

Do individual differences in face recognition ability moderate the other ethnicity effect?

Individuals are better at recognizing faces from their own ethnic group compared with other ethnicity faces-the other-ethnicity effect (OEE). This finding is said to reflect differences in experience and familiarity to faces from other ethnicities relative to faces corresponding with the viewers' ethnicity. However, own-ethnicity face recognition performance ranges considerably within a population, from very poor to extremely good. In addition, within-population recognition performance on other-ethnicity faces can also vary considerably with some individuals being classed as "other ethnicity face blind" (Wan et al., 2017). Despite evidence for considerable variation in performance within population for faces of both types, it is currently unclear whether the magnitude of the OEE changes as a function of this variability. By recruiting large-scale multinational samples, we investigated the size of the OEE across the full range of own and other ethnicity face performance while considering measures of social contact. We find that the magnitude of the OEE is remarkably consistent across all levels of within-population own- and other-ethnicity face recognition ability, and this pattern was unaffected by social contact measures. These findings suggest that the OEE is a persistent feature of face recognition performance, with consequences for models built around very poor, and very good face recognizers. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Searching for illusory motion.

In a series of four experiments, standard visual search was used to explore whether the onset of illusory motion pre-attentively guides vision in the same way that the onset of real-motion is known to do. Participants searched for target stimuli based on Akiyoshi Kitaoka's classic illusions, configured so that they either did or did not give the subjective impression of illusory motion. Distractor items always contained the same elements as target items, but did not convey a sense of illusory motion. When target items contained illusory motion, they popped-out, with flat search slopes that were independent of set size. Search for control items without illusory motion - but with identical structural differences to distractors - was slow and serial in nature (> 200 ms/item). Using a nulling task, we estimated the speed of illusory rotation in our displays to be approximately 2 °/s. Direct comparison of illusory and real-motion targets moving with matched velocity showed that illusory motion targets were detected more quickly. Blurred target items that conveyed a weak subjective impression of illusory motion gave rise to serial but faster (< 100 ms/item) search than control items. Our behavioral findings of parallel detection across the visual field, together with previous imaging and neurophysiological studies, suggests that relatively early cortical areas play a causal role in the perception of illusory motion. Furthermore, we hope to re-emphasize the way in which visual search can be used as a flexible, objective measure of illusion strength.

Anchoring versus spatial filtering accounts of simultaneous lightness contrast.

The oldest lightness illusion is called simultaneous contrast. A gray square placed on a black background appears lighter than an identical gray square placed on a white background. For over a hundred years, this illusion has been generally attributed to lateral inhibition or spatial filtering. Receptor cells stimulated by the gray square on the white background are strongly inhibited by nearby cells stimulated by the bright white background. Recently, a new explanation for this illusion was proposed as part of a larger theory of lightness called anchoring theory. The lightness of each target square is computed relative to the highest luminance in its local framework (consisting of only the target and its surrounding background) and relative to the highest luminance in the entire display. For each target, perceived lightness is held to depend on a weighted average of these two computations. According to this story, the contrast illusion stems mostly from the tendency of the gray square on the black background to rise toward white, its computed value in its local framework. We report six experiments in which these two theories of simultaneous contrast are pitted against each other. In each case, the results favor the anchoring model. The difficulty of deriving predictions from the spatial filtering models is discussed, along with the ease of deriving highly specific predictions from the anchoring model.

Horizontal-vertical illusion in mental imagery: quantitative evidence.

The present study had two main goals: (1) to investigate the difference between perception and mental imagery using a visual illusion as a stimulus; (2) to inspect gender related differences in perception and imagery. Our main hypothesis, that there would be no differences between perception and mental imagery, was motivated by previous neuroimaging data. Unlike these neuroimaging studies that demonstrate great similarity between the two processes, results obtained in behavioral studies have not always been consistent. We assumed that this inconsistency was a consequence of methodological differences. Hence, we explored the two processes with a modified behavioral procedure. The additional exploration of gender differences was motivated by the discrepancy between our findings and the existing literature. In two experiments, participants estimated the lines constituting the horizontal-vertical illusion, either in perception or imagery task. Results confirmed that there was no significant difference between perception and imagery: the illusion was equally strong in both tasks. In the second experiment, an additional factor was tested, stimulus size. The results showed that, although there was no significant difference in illusion strength, there was a gender difference in the size of mental image for medium and large stimuli. While male subjects performed equally in the two tasks, female subjects tended to underestimate size in the imagery task. This tendency intensified as the stimulus size increased. Our results not only inform us about the status of illusions in imagery but also offer some answers about the spatial nature of mental representations. We hope that such precise measurements of mental representation might provide better understanding of reasoning that uses mental images.

Side flankers produce less crowding, but only for letters.

Identification of isolated and crowded letter (B, D, F, G, K, N, L, S, T) and symbol stimuli (%, /, ?, @, }, <, £, §, µ) was examined across the visual field in a two-alternative forced-choice match-to-sample task (2AFC-MTS). During isolated presentation, identification accuracy did not differ between the two stimulus types. Identification rates for the central characters within the three-character strings were higher for letters than for symbols at the horizontal and vertical meridian (Experiment 1), and at diagonal locations (Experiment 2). However, this reduction of parafoveal letter crowding was present in horizontally but not in vertically oriented strings of stimuli. The same pattern of results was replicated in the periphery of the visual field (Experiment 3). The obtained results are in agreement with the proposition that the receptive fields of letter detectors are modified during reading acquisition, in order to support efficient letter identification (Tydgat & Grainger, 2009). However, the pervasive presence of the effect across the visual field suggests that it could originate from a non-retinotopic stage of visual processing.

Information extraction from shadowed regions in images: an eye movement study.

Natural scenes often contain variations in local luminance as a result of cast shadows and illumination from different directions. When making judgments about such scenes, it may be hypothesized that darker regions (with lower relative contrast due to a lack of illumination) are avoided as they may provide less detailed information than well-illuminated areas. We here test this hypothesis, first by presenting participants images of faces that were digitally modified to simulate the effect of a shadow over half of the image, and second by presenting photographs of faces taken with side illumination, also resulting in the appearance of a shadow across half of the face. While participants viewed these images, they were asked to perform different tasks on the images, to allow for the presentation of the different versions of each image (left shadow, right shadow, no shadow), and to distract the observers from the contrast and illumination manipulations. The results confirm our hypothesis and demonstrate that observers fixate the better illuminated regions of the images.

Grouping Factors and the Reverse Contrast Illusion.

In simultaneous lightness contrast, two identical gray target squares lying on backgrounds of different intensities appear different in lightness. Traditionally, this illusion was explained by lateral inhibitory mechanisms operating retinotopically. More recently, spatial filtering models have been preferred. We report tests of an anchoring theory account in which the illusion is attributed to grouping rules used by the visual system to compute lightness. We parametrically varied the belongingness of two gray target bars to their respective backgrounds so that they either appeared to group with a set of bars flanking them, or they appeared to group with their respective backgrounds. In all variations, the retinal adjacency of the gray squares and their backgrounds was essentially unchanged. We report data from seven experiments showing that manipulation of the grouping rules governs the size and direction of the simultaneous lightness contrast illusion. These results support the idea that simultaneous lightness contrast is the product of anchoring within perceptual groups.

The roles of image decomposition and edge curvature in the 'snake' lightness illusion.

The snake illusion is an effect in which the lightness of target patches is strongly affected by the luminance of remote patches. One explanation is that such images are decomposed into a pattern of illumination and a pattern of reflectance, involving a classification of luminance edges into illumination and reflectance edges. Based on this decomposition, perceived reflectance is determined by discounting the illumination. A problem for this account is that image decomposition is not unique, and that different decompositions may lead to different lightness predictions. One way to rule out alternative decompositions and ensure correct predictions is to postulate that the visual system tends to classify curved luminance edges as reflectance edges rather than illumination edges. We have constructed several variations of the basic snake display in order to test the proposed curvature constraint and the more general image decomposition hypothesis. Although the results from some displays have confirmed previous findings of the effect of curvature, the general pattern of data questions the relevance of the shape of luminance edges for the determination of lightness in this class of displays. The data also argue against an image decomposition mechanism as an explanation of this effect. As an alternative, a tentative neurally based account is sketched.

Grouping illumination frameworks.

According to Koffka (1935), the lightness of a target surface is determined by the relationship between the target and the illumination frame of reference to which it belongs. However, each scene contains numerous illumination frames, and judging each one separately would lead to an enormous amount of computing. Grouping those frames that are in the same illumination would simplify the computation. We report a series of experiments demonstrating that nonadjacent regions of the visual field under the same illumination level are perceptually grouped together and function, to some extent, as a single framework. A small coplanar group of patches under its own illumination exhibits compression of perceived range of gray shades. We obtained the reduction in compression in the presence of an identically illuminated 25-patch Mondrian tableau mounted nearby the coplanar group. The influence of the Mondrian display was reduced when it was (a) moved laterally away from the test display, (b) moved farther back in depth from the test display, or (c) rotated to a different orientation.

Bi-dimensional semantic scales: the embodied maps of meanings / Escala semántica bidimensional: La corporeidad de los mapas de significados

Osgood developed the semantic differential to bridge the phenomena from semantics and perception, and we applied its modified version to investigate current issues in cognitive science. We used two-dimensional rather than one-dimensional space to position nominal word items, and subjected data to multidimensional scaling (MDS). In Experiment 1 (paper-and-pencil) participants judged concrete and abstract nouns on seven bipolar semantic differential scales in three perceptual modalities: visual, auditory and touch. Six months later, in Experiment 2 (computer-assisted), the same participants mapped the same ten nouns on a balanced subset of two-dimensional planes. Our findings support the hypothesis that semantic space is physically constrained. MDS over one-dimensional ratings from Experiment 1 resulted in a particular two-dimensional solution. This two-dimensional combination was very similar to one of the raw two-dimensional maps from Experiment 2. We then concluded that this particular raw two-dimensional map is highly informative, as it captures almost all differences between word items in the given set of perceptual opposites. Its informativeness proved to be robust to experimental administration (paper-and-pencil vs. computer-assisted) and scale-orientations (horizontal vs. vertical). Recent theories, such as Barsalou's perceptual theory of knowledge, capture the tradition of conceptualizing all knowledge as inherently perceptual. Our results strongly support these theories.

Osgood desarrolló el diferencial semántico para investigar los fenómenos desde la semántica y la percepción, y aplicamos su versión modificada para investigar temas actuales en ciencia cognitiva. Utilizamos dos dimensiones en lugar de un espacio unidimensional para posicionar palabras nominales y datos sujetos a escalamiento multidimensional (MDS). En el experimento 1 (papel y lápiz) participantes consideraron sustantivos concretos y abstractos en siete escalas de diferencial semántico bipolar en tres modalidades per-ceptuales: visual, auditivo y táctil. Seis meses más tarde, en el Experimento 2 (asistida por ordenador), los mismos participantes asignaron los mismos diez sustantivos en un subconjunto equilibrado de planos bidimensionales. Nuestros resultados apoyan la hipótesis de que el espacio semántico está limitado físicamente. Las calificaciones unidimensionales sobre MDS del Experimento 1 dieron como resultado una solución de dos dimensiones particular. Esta combinación de dos dimensiones fue muy similar a uno de los mapas de dos dimensiones en bruto del Experimento 2. Se concluyó que este mapa particular de dos dimensiones es altamente informativo, ya que captura casi todas las diferencias entre las palabras en el conjunto dado de los opuestos perceptuales. Esta información demostró ser sólida a la administración experimental (papel y lápiz versus asistida por computador) y las orientaciones de la escala (horizontal y vertical). Teorías recientes, como la teoría del conocimiento perceptual de Barsalou, captura la tradición de la conceptualización del conocimiento como inherentemente perceptual. Nuestros resultados apoyan firmemente estas teorías.

Lightness of an object under two illumination levels.

Anchoring theory (Gilchrist et al, 1999 Psychological Review 106 795-834) predicts a wide range of lightness errors, including failures of constancy in multi-illumination scenes and a long list of well-known lightness illusions seen under homogeneous illumination. Lightness values are computed both locally and globally and then averaged together. Local values are computed within a given region of homogeneous illumination. Thus, for an object that extends through two different illumination levels, anchoring theory produces two values, one for the patch in brighter illumination and one for the patch in dimmer illumination. Observers can give matches for these patches separately, but they can also give a single match for the whole object. Anchoring theory in its current form is unable to predict these object matches. We report eight experiments in which we studied the relationship between patch matches and object matches. The results show that the object match represents a compromise between the match for the patch in the field of highest illumination and the patch in the largest field of illumination. These two principles are parallel to the rules found for anchoring lightness: highest luminance rule and area rule.