Effects of Culture and the Urban Environment on the Development of the Ebbinghaus Illusion

Perception of optical illusions in ungulates: insights from goats, sheep, guanacos and llamas

Optical illusions have long been used in behavioural studies to investigate the perceptual mechanisms underlying vision in animals. So far, three studies have focused on ungulates, providing evidence that they may be susceptible to some optical illusions, in a way similar to humans. Here, we used two food-choice tasks to study susceptibility to the Müller-Lyer and Delboeuf illusions in 17 captive individuals belonging to four ungulate species (Lama guanicoe, Lama glama, Ovis aries, Capra hircus). At the group level, there was a significant preference for the longer/larger food over the shorter/smaller one in control trials. Additionally, the whole group significantly preferred the food stick between two inward arrowheads over an identical one between two outward arrowheads in experimental trials of the Müller-Lyer task, and also preferred the food on the smaller circle over an identical one on the larger circle in the experimental trials of the Delboeuf task. Group-level analyses further showed no significant differences across species, although at the individual level we found significant variation in performance. Our findings suggest that, in line with our predictions, ungulates are overall susceptible to the Müller-Lyer and the Delboeuf illusions, and indicate that the perceptual mechanisms underlying size estimation in artiodactyls might be similar to those of other species, including humans.

The relationships between urbanicity, general cognitive ability, and susceptibility to the Ebbinghaus illusion

Previous studies have shown that, in samples of non-Western observers, susceptibility to the Ebbinghaus illusion is stronger in urban than rural dwellers. While such relationship between illusion strength and urbanicity has often been ascribed to external factors (such as the visual impact of the environment), the present study explored the possibility that it is instead mediated by general cognitive ability, an internal factor. We recruited a sample of remote Namibians who varied in their level of urbanicity, and measured their susceptibility to the Ebbinghaus illusion, their levels of education and literacy, and their general cognitive ability. The results showed that urbanicity was related to Ebbinghaus susceptibility, and that general cognitive ability, literacy and education did not mediate this effect, which is reassuring with regard to the findings of previous studies that did not control for these variables. However, we found robust relationships between urbanicity, on the one hand, and cognitive ability, education and literacy, on the other, which advocates for careful consideration of the impact of the latter variables in studies about the cognitive effects of urban environments.

Visual attention across cultures: Similarities and differences in child development and maternal attention styles

Previous cross-cultural research has described two different attention styles: a holistic style, characterized by context-sensitive processing, generally associated with interdependent cultural contexts, and an analytic style, a higher focus on salient objects, generally found in independent cultural contexts. Though a general assumption in the field is that attention styles are gradually socialized in culture-specific interactions in childhood, empirical evidence for the proximal mechanisms underlying this development is scarce. This study aimed to document the emergence of cross-cultural differences in attention styles in three cultural contexts differing in social orientations, namely in urban middle-class families from Münster, Germany (i.e., more independent context), and Kyoto, Japan, and Indigenous-heritage families from Cotacachi, Ecuador (i.e., more interdependent contexts). Furthermore, to test the assumption that caregivers' attention guidance is one of the forces driving differential development, we investigated how caregivers guide children's attention. In total, 270 children between 4 and 9 years of age and their mothers participated in three tasks: an eye-tracking task, a picture description task and a forced-choice recognition task. Results indicate a mixed pattern of findings: While some tasks revealed the expected cultural differences, namely a higher object focus in Münster compared to Kyoto and Cotacachi, others did not. Regarding caregivers' attention guidance, we found that mothers in Münster more strongly emphasized the focal object than mothers in Kyoto and Cotacachi. The results are discussed in terms of culture-specific developmental trajectories and the generalizability of attentional processes across tasks and cultural contexts. RESEARCH HIGHLIGHTS: We investigated visual attention styles in 4- to 9-year-old children and their mothers from urban Germany, urban Japan, and rural Ecuador in three different tasks. Special emphasis lied on mothers' verbal attention guidance toward their children as a proximal mechanism underlying the emergence of culture-specific attention styles. Mothers from urban Germany guided their children's attention in more analytic ways than mothers from urban Japan and rural Ecuador. The relevance of verbal attention guidance in the development of culture-specific attention styles has been demonstrated beyond the East-West dichotomy.

Visual context processing and its development in gamers and non-gamers

Visual context processing was investigated in both action video game players and nonplayers using the Ebbinghaus illusion task (N = 312, 39.4% female) in a cross-sectional study design. When presented in context, players showed markedly poorer target size discrimination accuracy compared with nonplayers in the 6-, 7-, 8-, and 9-years old age groups, but this difference was reduced in 10-years old group and diminished in adults. When presented in isolation (no-context), the two groups displayed similar performance in all age groups. Furthermore, nonplayers (linear) and players (bell curve) showed profoundly different age-related differences in context processing. These findings provide evidence that players might have enhanced perceptual bias to process visual context in the transition from early childhood to early adolescence, and the differences between the two groups start at early ages and continue with distinct developmental profiles.

A test of the ecological valence theory of color preference, the case of Arabic

Humans have systematic and reliable color preferences. The dominant account of color preference is that individuals like some colors more than others due to the valence of objects that they associate with colors (Ecological Valence Theory). In support of this theory, Palmer and Schloss show that the average valence of objects associated with a color, when weighted (the WAVE), explains up to 80% of the variation in color preference for adults from the United States (US). Here we investigate whether Ecological Valence Theory can account for the color preferences of female and male adults from Saudi Arabia to test how well the theory generalizes across cultures and how well it accounts for sex differences in color preference. We also extend the investigation of EVT by investigating whether abstract concept associations as well as object associations can account for preference. Saudi adults' color preferences, color object and concept associations, and association valence ratings were collected, and the WAVE was computed and correlated with preference ratings. The WAVE accounted for no more than half of the variance in Saudi color preferences, although there was some degree of sex specificity in the relationship of the WAVE and color preference. Adding abstract concept associations did not account for more variance than object associations alone, but the number of abstract concept associations did account for a significant amount of the variance in color preference for females, but not males. The findings converge with other cross-cultural studies in suggesting that the success of EVT in accounting for color preference varies across cultures and indicates that additional factors other than color associations are likely also at play.

Urban and rural environments differentially shape multisensory perception in ageing

Recent studies suggest that the lived environment can affect cognition across the lifespan. We examined, in a large cohort of older adults (n = 3447), whether susceptibility to a multisensory illusion, the Sound-Induced Flash Illusion (SIFI), was influenced by the reported urbanity of current and childhood (at age 14 years) residence. If urban environments help to shape healthy perceptual function, we predicted reduced SIFI susceptibility in urban dwellers. Participants reporting urban, compared with rural, childhood residence were less susceptible to SIFI at longer Stimulus-Onset Asynchronies (SOAs). Those currently residing in urban environments were more susceptible to SIFI at longer SOAs, particularly if they scored low on general cognitive function. These findings held even when controlling for a several covariates, such as age, sex, education, social participation and cognitive ability. Exposure to urban environments in childhood may influence individual differences in perception and offer a multisensory perceptual benefit in older age.

Cultural Differences in Face Recognition and Potential Underlying Mechanisms

The ability to recognize a face is crucial for the success of social interactions. Understanding the visual processes underlying this ability has been the focus of a long tradition of research. Recent advances in the field have revealed that individuals having different cultural backgrounds differ in the type of visual information they use for face processing. However, the mechanisms that underpin these differences remain unknown. Here, we revisit recent findings highlighting group differences in face processing. Then, we integrate these results in a model of visual categorization developed in the field of psychophysics: the RAP framework. On the basis of this framework, we discuss potential mechanisms, whether face-specific or not, that may underlie cross-cultural differences in face perception.

Changing cultures, changing brains: A framework for integrating cultural neuroscience and cultural change research

Cultural neuroscience research has provided substantial evidence that culture shapes the brain by providing systematically different sets of experiences. However, cultures are ever-changing in response to the physical and social environment. In the present paper, we integrate theories and methods from cultural neuroscience with the emerging body of research on cultural change and suggest several ways in which the two fields can inform each other. First, we propose that the cultural change perspective helps us reexamine what is meant by culturally typical experiences, which are shaped by the dynamic interaction between cultural norms, values, meanings, and other environmental constraints on behavior. It also allows us to make predictions about the variability/stability of cultural neural differences over time. Then, we discuss how methods used in cultural change research may be applied to cultural neuroscience research and vice versa. We end with a "blue sky vision" for a neuroscience of cultural change.

The development of the Poggendorff illusion in typically developing children

We examined how the strength of the Poggendorff illusion changes with age in typically developing children. To this end, we recruited children aged 6 to 14 years and quantified the degree to which they experienced the illusion. The illusion was strongest in the youngest children and decreased with age logarithmically-reaching adult levels (as established by an earlier study) by 21.6 years, as determined by nonlinear interpolation. We also measured the ability to align two lines together in a nonillusory condition, receptive language, and abstract reasoning to determine whether changes in illusion strength were also associated with these factors. Alignment-matching abilities, receptive language, and abstract reasoning increased with age. However, only receptive language and abstract reasoning were correlated with illusion strength. Abilities in alignment matching were not related to illusion strength and reached adult levels (as established by a previous study) earlier at 14.7 years, as determined by nonlinear interpolation. A multiple regression analysis further revealed that receptive language and abstract reasoning did not contribute beyond their shared variance with age. Based on these findings, we suggest that the illusion is exaggerated in early development and attenuates as low-level and high-level processes mature. The theoretical implications of these findings are discussed.

A genome-wide association study reveals a substantial genetic basis underlying the Ebbinghaus illusion

The Ebbinghaus illusion (EI) is an optical illusion of relative size perception that reflects the contextual integration ability in the visual modality. The current study investigated the genetic basis of two subtypes of EI, EI overestimation, and EI underestimation in humans, using quantitative genomic analyses. A total of 2825 Chinese adults were tested on their magnitudes of EI overestimation and underestimation using the method of adjustment, a standard psychophysical protocol. Heritability estimation based on common single nucleotide polymorphisms (SNPs) revealed a moderate heritability (34.3%) of EI overestimation but a nonsignificant heritability of EI underestimation. A meta-analysis of two phases (phase 1: n = 1986, phase 2: n = 839) of genome-wide association study (GWAS) discovered 1969 and 58 SNPs reaching genome-wide significance for EI overestimation and EI underestimation, respectively. Among these SNPs, 55 linkage-disequilibrium-independent SNPs were associated with EI overestimation in phase 1 with genome-wide significance and their associations could be confirmed in phase 2 cohort. Gene-based analyses found seven genes to be associated with EI overestimation at the genome-wide level, two from meta-analysis, and five from classical two-stage analysis. Overall, this study provided consistent evidence for a substantial genetic basis of the Ebbinghaus illusion.

The Development of Context-Sensitive Attention Across Cultures: The Impact of Stimulus Familiarity

Across cultures, there are marked differences in visual attention that gradually develop between 4 and 6 years of age. According to the social orientation hypothesis, people in interdependent cultures should show more pronounced context sensitivity than people in independent cultures. However, according to the differential familiarity hypothesis, the focus on the salient object should also depend on the familiarity of the stimulus; people will focus more on the focal object (i.e., less context sensitivity), if it is a less familiar stimulus. To examine the differences in visual attention between interdependent and independent cultures while taking into account stimulus familiarity, this study used an eye-tracking paradigm to assess visual attention of participants between 4 and 20 years who came from urban middle-class families from Germany (n = 53; independent culture) or from Nso families in a rural area in Cameroon (n = 50; interdependent culture). Each participant saw four sets of stimuli, which varied in terms of their familiarity: (1) standard stimuli, (2) non-semantic stimuli, both more familiar to participants from Germany, (3) culture-specific matched stimuli, and (4) simple stimuli, similarly familiar to the individuals of both cultures. Overall, the findings show that mean differences in visual attention between cultures were highly contingent on the stimuli sets: In support of the social orientation hypothesis, German participants showed a higher object focus for the culture-specific matched stimuli, while there were no cultural differences for the simple set. In support of the differential familiarity hypothesis, the Cameroonian participants showed a higher object focus for the less familiar sets, namely the standard and non-semantic sets. Furthermore, context sensitivity correlated across all the sets. In sum, these findings suggest that the familiarity of a stimulus strongly affects individuals’ visual attention, meaning that stimulus familiarity needs to be considered when investigating culture-specific differences in attentional styles.

The Development of Context-Sensitive Attention in Urban and Rural Brazil

Human perception differs profoundly between individuals from different cultures. In the present study, we investigated the development of context-sensitive attention (the relative focus on context elements of a visual scene) in a large sample (N = 297) of 5- to 15-year-olds and young adults from rural and urban Brazil, namely from agricultural villages in the Amazon region and the city of São Paulo. We applied several visual tasks which assess context-sensitive attention, including an optical illusion, a picture description, a picture recognition and a facial emotion judgment task. The results revealed that children and adults from the urban sample had a higher level of context-sensitive attention, when compared to children and adults from the rural sample. In particular, participants from São Paulo were more easily deceived by the context elements in an optical illusion task and remembered more context elements in a recognition task than participants from rural Amazon villages. In these two tasks, context-sensitivity increased with age. However, we did not find a cultural difference in the picture description and the facial emotion judgment task. These findings support the idea that visual information processing is highly dependent on the culture-specific learning environments from very early in development. Specifically, they are more consistent with accounts that emphasize the role of the visual environment, than with the social orientation account. However, they also highlight that further research is needed to disentangle the diverse factors that may influence the early development of visual attention, which underlie culture-specific developmental pathways.

Urbanisation, the arousal system, and covert and overt attentional selection

Urbanisation is growing rapidly. We review evidence that this growth is altering the default information processing style of human beings by impacting both overt and covert processes of attentional selection (i.e. attentional selection with and without eye movements respectively), in ways consistent with reduced attentional engagement and increased exploration. While the factors and systems mediating these effects are likely to be many and various, we focus on one system which may be responsible for mediating effects on both covert and overt attentional selection. Specifically, the neuromodulatory locus coeruleus-norepinephrine (LC-NE) system is key to regulating cognitive function in a behaviourally relevant and arousal-dependent manner and therefore well suited to supporting adaptation to the profound socio-ecological changes inherent in urbanisation.

Children's perception of visual and auditory ambiguity and its link to executive functions and creativity

The phenomenon of perceptual bistability provides insights into aspects of perceptual processing not normally accessible to everyday experience. However, most experiments have been conducted in adults, and it is not clear to what extent key aspects of perceptual switching change through development. The current research examined the ability of 6-, 8-, and 10-year-old children (N = 66) to switch between competing percepts of ambiguous visual and auditory stimuli and links between switching rate, executive functions, and creativity. The numbers of switches participants reported in two visual tasks (ambiguous figure and ambiguous structure from motion) and two auditory tasks (verbal transformation and auditory streaming) were measured in three 60-s blocks. In addition, inhibitory control was measured with a Stroop task, set shifting was measured with a verbal fluency task, and creativity was measured with a divergent thinking task. The numbers of perceptual switches increased in all four tasks from 6 to 10 years of age but differed across tasks in that they were higher in the verbal transformation and ambigous structure-from-motion tasks than in the ambigous figure and auditory streaming tasks for all age groups. Although perceptual switching rates differed across tasks, there were predictive relationships between switching rates in some tasks. However, little evidence for the influence of central processes on perceptual switching was found. Overall, the results support the notion that perceptual switching is largely modality and task specific and that this property is already evident when perceptual switching emerges.

The local perceptual bias of a non-remote and educated population

In 1977, Navon argued that perception is biased towards the processing of global as opposed to local visual information (or the forest before the trees) and implicitly assumed this to be true across places and cultures. Previous work with normally developing participants has supported this assumption except in one extremely remote African population. Here, we explore local-global perceptual bias in normally developing African participants living much less remotely than the African population tested previously. These participants had access to modern artefacts and education but presented with a local bias on a similarity-matching Navon task, contrary to Navon's assumptions. Nevertheless, the urban and more educated amongst these participants showed a weaker local bias than the rural and less educated participants, suggesting an effect of urbanicity and education in driving differences in perceptual bias. Our findings confirm the impact of experience on perceptual bias and suggest that differences in the impact of education and urbanicity on lifestyles around the world can result in profound differences in perceptual style. In addition, they suggest that local bias is more common than previously thought; a global bias might not be universal after all.

Context-sensitive attention is socialized via a verbal route in the parent-child interaction

The way humans perceive and attend to visual scenes differs profoundly between individuals. This is most compellingly demonstrated for context-sensitivity, the relative attentional focus on focal objects and background elements of a scene, in cross-cultural comparisons. Differences in context-sensitivity have been reported in verbal accounts (e.g. picture descriptions) and in visual attention (e.g., eye-tracking paradigms). The present study investigates (1) if the way parents verbally guide the attention of their children in visual scenes is associated with differences in children’s context-sensitivity and (2) if verbal descriptions of scenes are related to early visual attention (i.e., gaze behavior) in 5-year-old children and their parents. Importantly, the way parents verbally described visual scenes to their children was related to children’s context-sensitivity, when describing these scenes themselves. This is, we found a correlation in the number of references made to the object versus the background as well as the number of relations made between different elements of a scene. Furthermore, verbal descriptions were closely related to visual attention in adults, but not in children. These findings support our hypotheses that context-sensitivity is socialized via a verbal route and that visual attention processes align with acquired narrative structures only later in development, after the preschool years.

Visual attention in 5-year-olds from three different cultures

Cognitive processes differ markedly between children from different cultures, with best evidence for attention to visual scenes and the activities of others. Children from urban Western cultures tend to focus on focal objects, whereas children from urban East-Asian cultures rather attend to contextual elements of a visual scene. Regarding the attention to others' activities, children from subsistence-based farming communities often observe several activities simultaneously, while children from urban Western contexts focus on activities sequentially. Here we assessed 144 5-year-old children from three prototypical cultural contexts (urban Germany, rural Cameroon, urban Japan) to investigate variations in attention across a variety of tasks. Attention to the elements of a visual scene was assessed in an optical illusion task, in picture descriptions and an eye-tracking paradigm. Attention to and learning from others' activities was assessed in a parallel action task and a rule-based game. Some tasks indicated higher context-sensitive attention in urban Japan, while other findings indicated higher context-sensitive attention in urban Germany. Levels of parallel attention and learning from others' activities were lower in rural Cameroonian children compared to the urban samples. Across tasks, the visual attention measures were unrelated. These findings substantiate that culture has a profound influence on early cognitive development, already in the preschool years. Furthermore, they raise critical questions about the early origins of cultural specificities in attention and the generalizability of attention phenomena beyond specific tasks and populations.

Is the Ebbinghaus illusion a size contrast illusion?

The Ebbinghaus illusion, in which a central target surrounded by larger context figures looks smaller than when surrounded by smaller context figures, is usually classified as a size contrast illusion. Thus "size contrast" is the dominant account of this effect. However, according to an alternative "contour interaction" account this phenomenon has little to do with size contrast but is rather caused by distance-dependent attractive and repulsive interactions between neural representation of contours. Here evidence is presented against the size contrast account and consistent with the contour interaction account. Experiment 1 was a control study confirming that the illusion can be obtained using displays consisting only of squares, which are more convenient to manipulate than the standardly used circles. In Experiment 2, the standard configuration involving small context figures surrounding the target was compared to a novel configuration, which involved many "spread" small context figures. The illusory effect of the standard context was stronger than the illusory effect of the spread context, in accord with the prediction of the contour interaction account, and contrary to the prediction of the size contrast account. In Experiment 3 two novel configurations were used, based on standard and spread contexts. The results were in accord with the prediction of the contour interaction account, whereas the size contrast account had no prediction because the stimuli did not involve conventional size contrast. Additional aspects of the stimuli and an account of the illusion based on a perspective interpretation are also discussed.

Susceptibility to Ebbinghaus and Müller-Lyer illusions in autistic children: a comparison of three different methods

BACKGROUND

Studies reporting altered susceptibility to visual illusions in autistic individuals compared to that typically developing individuals have been taken to reflect differences in perception (e.g. reduced global processing), but could instead reflect differences in higher-level decision-making strategies.

METHODS

We measured susceptibility to two contextual illusions (Ebbinghaus, Müller-Lyer) in autistic children aged 6-14 years and typically developing children matched in age and non-verbal ability using three methods. In experiment 1, we used a new two-alternative-forced-choice method with a roving pedestal designed to minimise cognitive biases. Here, children judged which of two comparison stimuli was most similar in size to a reference stimulus. In experiments 2 and 3, we used methods previously used with autistic populations. In experiment 2, children judged whether stimuli were the 'same' or 'different', and in experiment 3, we used a method-of-adjustment task.

RESULTS

Across all tasks, autistic children were equally susceptible to the Ebbinghaus illusion as typically developing children. Autistic children showed a heightened susceptibility to the Müller-Lyer illusion, but only in the method-of-adjustment task. This result may reflect differences in decisional criteria.

CONCLUSIONS

Our results are inconsistent with theories proposing reduced contextual integration in autism and suggest that previous reports of altered susceptibility to illusions may arise from differences in decision-making, rather than differences in perception per se. Our findings help to elucidate the underlying reasons for atypical responses to perceptual illusions in autism and call for the use of methods that reduce cognitive bias when measuring illusion susceptibility.

Complexity As Key to Designing Cognitive-Friendly Environments for Older People

The lived environment is the arena where our cognitive skills, preferences, and attitudes come together to determine our ability to interact with the world. The mechanisms through which lived environments can benefit cognitive health in older age are yet to be fully understood. The existing literature suggests that environments which are perceived as stimulating, usable and aesthetically appealing can improve or facilitate cognitive performance both in young and older age. Importantly, optimal stimulation for cognition seems to depend on experiencing sufficiently stimulating environments while not too challenging. Environmental complexity is an important contributor to determining whether an environment provides such an optimal stimulation. The present paper reviews a selection of studies which have explored complexity in relation to perceptual load, environmental preference and perceived usability to propose a framework which explores direct and indirect environmental influences on cognition, and to understand these influences in relation to aging processes. We identify ways to define complexity at different environmental scales, going from micro low-level perceptual features of scenes, to design qualities of proximal environments (e.g., streets, neighborhoods), to broad geographical areas (i.e., natural vs. urban environments). We propose that studying complexity at these different scales will provide new insight into the design of cognitive-friendly environments.