The Experts below are selected from a list of 10155 Experts worldwide ranked by ideXlab platform
Chatterjee Sumita - One of the best experts on this subject based on the ideXlab platform.
-
Differences in object perception: a comparison of Indian and British participants on scene and silhouetted object perception tasks
2021Co-Authors: Chatterjee SumitaAbstract:Background: The impact of contrasting societal structures on various neuropsychological test performances is well recognized within the clinical community. Much of the research to date has focused on showing that a difference in performance exists, and less so on understanding specifically which aspects of the societies’ structure or “culture” are driving these differences. Many studies have explored conscious behavioral responses between individuals that are deemed “Western” and “Eastern-mainly Americans and Chinese-on visual Perceptual tasks. Authors of these studies extrapolated their results to a theory suggesting that individuals who originated from Western/individualistic societies tend to implement an analytical cognitive style, attending to more focal/local information; and those who originate from Eastern/collectivist societies implement a holistic cognitive style, attending to the background/global information. With the rapid rise in technology starting from the turn of the century, one’s ability to understand various physiological mechanisms related to visual perception increased, and with it came a rise in studies investigating the translation of the aforementioned theory as a kinetic behavioral response-eye movements and neural activity specifically. The results of the studies investigating this theory within object/scene perception have been mixed, some confirming this theory while others showing little to no evidence of it. However, it is also important to note that this theory is limited to mainly Americans and Chinese individuals, and is unclear as to whether it can be confidently expanded to other cultures that are historically considered as part of the “West” and “East”, e.g. British and Indians, two cultural groups that have not been used in comparison with each other in cultural visual Perceptual studies. This theory, along with the advances in technological techniques, has also not been explored as an explanation for performance differences seen in various neuropsychological visual Perceptual tests. One example of observed performance differences in neuropsychological tests of perception is in the Visual Object Space Perception (VOSP) Battery. More specifically, on the Silhouettes subtest, a subtest that requires participants to identify objects from silhouettes of animals and man-made objects. Indians performed significantly worse than their Spanish, Greek, and American counterparts; however the driving forces behind this difference remain unknown. Given this information, the purpose of this thesis is to use eye tracking, the most commonly used technology in cultural object/scene perception studies, to see if differences in eye movement pattern exist between British and Indian individuals, whether these differences emulate the West/East theory in Perceptual processing, and finally, whether these patterns of eye movements can help explain the performance differences seen between Indians and the British on the Silhouettes subtest. Method: I first conducted a systematic review to establish in what way eye tracking, fMRI, and EEG are able to detect differences in perception between distinct cultural groups during scene or object perception. In addition to this, the systematic review also investigated how cultural concepts, e.g. East vs West, Individualism vs Collectivism, etc., are used to explain any differences seen, and the specific cultural groups used as exemplars of the cultural concepts, e.g. Chinese vs. American, Japanese vs. American, etc. to represent East vs West, Individualism vs Collectivism, etc. My first experimental study utilized a scene perception recognition task, the most commonly used visual Perceptual paradigm, to establish whether differences in eye movement are seen between Indians and the British, and whether these differences followed the West/East theory. In addition, participants were also given the Singelis Self-Construal Scale, a scaled used to measure degree of collectivist or individualist values an individual holds. I incorporated this scale in order to see if the conceptual link made between West/East and individualism/collectivism in previous studies could be demonstrated. In the second experimental study, the findings of the first experimental study were used as a base to investigate whether comparable differences in eye movement patterns were also present when viewing the shadowed single objects from the Silhouettes subtest. The question of familiarity to the objects depicted in the Silhouettes subtest as a driving cultural factor either oppose to or in addition to the West/East theory of perception held strong relevance. Thus, my third experimental study investigated whether the self-reported degree of familiarity with the objects represented in the Silhouettes subtest influenced their ability to accurately identify them. Participants were also asked to physically indicate which parts of the image they felt caught their attention when looking at the picture. This was to see if the features that Indians and British participants felt they were attending to differed from each other, and whether this explained their chances of accurately identifying the objects. Findings: My systematic review suggested that the cultural concepts most commonly used to explain Perceptual differences were East Asians vs. Westerners, and Object/Context Independent vs Context/Context Dependent. The most common participant groups compared were Chinese/Chinese Singaporeans/Han Chinese and Americans. In terms of differences in perception, all but two studies found a cultural difference in at least one measurement. EEG and eye-tracking studies showed conflicting results among studies, but fMRI studies consistently showed differences between groups in neural activation for the processing of objects in scenes. British participants significantly out-performed the Indian participants in the memory recall portion of the first experimental study. A difference in eye movement was also present between Indians and the British only within the focal object; eye movement patterns in the background was not significantly different between the Indians and the British. When looking at the focal object, the British and Indians made a comparable number of shorter fixations and saccades, but made significantly fewer longer fixations and saccades than the Indians. The Singelis self-construal scale showed that Indians were slight more collectivist than the British but not significantly so. Singelis, regardless of which country participants were from, did not influence any of the eye movement patterns. My second experimental study showed that no significant difference in performance alone existed between Indians and the British; however a significant difference in performance was seen when analyzed across difficulty levels. Performance/accuracy was negatively correlated to the difficulty level of the object, and the British showed a greater declined in performance than the Indians. This is expected since the difficulty level of the objects was determined by the accuracy rates of each objects from the original UK normative data that the Silhouettes subtest was based on. In terms of eye movement data, the British showed a significantly greater saccade amplitude and saccade velocity than the Indians. No differences were seen in any other eye movement data. Singelis was not an influential variable in predicting accuracy or in any of the eye movement data. In third experimental study, I combined the performance data of the current study with the previous study and the integrated result re-enforced the findings of the second study. The British, overall, performed better than the Indians, but the difference did not reach significance. Performance/accuracy was, again, negatively correlated to the difficulty level of the object, for which, the British showed a greater declined in performance than the Indians. When examining the influence of familiarity on accuracy, results showed that the performance of the British were significantly influenced by how familiar they were with the object, however the performance of Indians remained unaffected. Furthermore, of all the incorrect answers given, participants claimed the correct answer to be a part of their thought process for only a small percentage (13% for the Indians and 3% for the British) of them. When asked about features that participants felt their attention was drawn towards, features indicated by Indians and the British largely overlapped. Conclusions: Though there is a difference in Perceptual Strategy between Indians and the British when viewing scenes, as evidenced by their eye movements, the strategies don’t follow the expected cognitive styles—analytic vs. holistic— of the West/East theory described in previous studies. This may be because the previously described cognitive styles have been examined mainly through studies of individuals who are American and Chinese, and thus the explanations developed may not fully encompass other types of cognitive styles that could possibly exist, or any variations of the analytical/holistic styles. None-the-less, the differences in eye movements seen between Indians and the British during scene perception were not evident during the viewing of the single, shadowed objects of the Silhouettes subtest suggesting that eye movement patterns used during scene perception and single object perception may not be directly interchangeable-how individuals go about looking at a scene may not be indicative of how individuals go about looking at a single object. Furthermore, though the overall difference in performance was not significant, a difference in performance was still seen between the Indians and the British on the Silhouettes Subtest which was driven by notable differences certain items. Self construal and familiarity were also not influential factors on overall performance which suggests that any performance difference may not be a result of any one factor but maybe be more specific to each item. Overall, I recommend that future research investigate the factors influencing the major performance differences seen on specific items of the Silhouettes subtest and to be cautious that factors may be unique to each case-what may be influential for one item may not be the same for a different item. This will allow for a clearer understanding of how to move forward in the test development of a Silhouettes subtest in the Indian context
Sabrina Hansmann-roth - One of the best experts on this subject based on the ideXlab platform.
-
The dress and individual differences in the perception of surface properties.
Vision research, 2017Co-Authors: Christoph Witzel, J. Kevin O'regan, Sabrina Hansmann-rothAbstract:Abstract This study investigates systematic individual differences in the way observers perceive different kinds of surface properties and their relationship to the dress, which shows striking individual differences in colour perception. We tested whether these individual differences have a common source, namely differences in Perceptual strategies according to which observers attribute features in two-dimensional images to surfaces or to their illumination. First, we reanalysed data from two previous experiments on the dress and colour constancy. The comparison of the two experiments revealed that the colour perception of the dress is strongly related to individual differences in colour constancy. Second, two online surveys measured individual differences in the perception of colour-ambiguous images including the dress, in colour constancy, in gloss perception, in the subjective grey-point, in colour naming, and in the perception of an image with ambiguous shading. The results of the surveys replicated and extended previous findings according to which individual differences in the colour perception of the dress are due to implicit assumptions about the illumination. However, results also showed that the individual differences for other phenomena were independent of the dress and of each other. Overall, these results suggest that the striking individual differences in dress colour perception are due to individual differences in the interpretation of illumination cues to achieve colour constancy. At the same time, they undermine the idea of an overall Perceptual Strategy that encompasses other phenomena more generally related to the interpretation of illumination and surface properties.
Barbara Hayesroth - One of the best experts on this subject based on the ideXlab platform.
-
an architecture for adaptive intelligent systems
Artificial Intelligence, 1995Co-Authors: Barbara HayesrothAbstract:Our goal is to understand and build comprehensive agents that function effectively in challenging niches. In particular, we identify a class of niches to be occupied by ''adaptive intelligent systems (AISs)''. In contrast with niches occupied by typical AI agents, AIS niches present situations that vary dynamically along several key dimensions: different combinations of required tasks, different configurations of available resources, contextual conditions ranging from benign to stressful, and different performance criteria. We present a small class hierarchy of AIS niches that exhibit these dimensions of variability and describe a particular AIS niche, ICU (intensive care unit) patient monitoring, which we use for illustration throughout the paper. To function effectively throughout the range of situations presented by an AIS niche, an agent must be highly adaptive. In contrast with the rather Stereotypie behavior of typical AI agents, an AIS must adapt several key aspects of its behavior to its dynamic situation: its Perceptual Strategy, its control mode, its choices of reasoning tasks to perform, its choices of reasoning methods for performing chosen tasks; and its meta-control Strategy for global coordination of all its behavior. We have designed and implemented an agent architecture that supports all of these different kinds of adaptation by exploiting a single underlying theoretical concept:An agent dynamically constructs explicit control plans to guide its choices among situation-triggered behaviors. The architecture has been used to build experimental agents for several AIS niches. We illustrate the architecture and its support for adaptation with examples from Guardian, an experimental agent for ICU monitoring.
Mauro Ursino - One of the best experts on this subject based on the ideXlab platform.
-
a biologically inspired neurocomputational model for audiovisual integration and causal inference
European Journal of Neuroscience, 2017Co-Authors: Cristiano Cuppini, Ladan Shams, Elisa Magosso, Mauro UrsinoAbstract:Recently, experimental and theoretical research has focused on the brain's abilities to extract information from a noisy sensory environment and how cross-modal inputs are processed to solve the causal inference problem to provide the best estimate of external events. Despite the empirical evidence suggesting that the nervous system uses a statistically optimal and probabilistic approach in addressing these problems, little is known about the brain's architecture needed to implement these computations. The aim of this work was to realize a mathematical model, based on physiologically plausible hypotheses, to analyze the neural mechanisms underlying multisensory perception and causal inference. The model consists of three layers topologically organized: two encode auditory and visual stimuli, separately, and are reciprocally connected via excitatory synapses and send excitatory connections to the third downstream layer. This synaptic organization realizes two mechanisms of cross-modal interactions: the first is responsible for the sensory representation of the external stimuli, while the second solves the causal inference problem. We tested the network by comparing its results to behavioral data reported in the literature. Among others, the network can account for the ventriloquism illusion, the pattern of sensory bias and the percept of unity as a function of the spatial auditory-visual distance, and the dependence of the auditory error on the causal inference. Finally, simulations results are consistent with probability matching as the Perceptual Strategy used in auditory-visual spatial localization tasks, agreeing with the behavioral data. The model makes untested predictions that can be investigated in future behavioral experiments.
Claudia Scherr - One of the best experts on this subject based on the ideXlab platform.
-
kinesthetic engagement in gestalt evaluation outscores analytical atomic feature evaluation in perceiving aging in crystallization images of agricultural products
PLOS ONE, 2021Co-Authors: Paul Doesburg, Jurgen Fritz, Miriam Athmann, Roya Bornhutter, Nicolaas Busscher, Uwe Geier, Gaby Mergardt, Claudia ScherrAbstract:There is an increasing interest in a systemic approach to food quality. From this perspective, the copper chloride crystallization method is an interesting asset as it enables an estimation of a sample’s ‘resilience’ in response to controlled degradation. In previous studies, we showed that an ISO-standardized visual evaluation panel could correctly rank crystallization images of diverse agricultural products according to their degree of induced degradation. In this paper we examined the role of contextual sensitivity herein, with the aim to further improve the visual evaluation. To this end, we compared subjects’ performance in ranking tests, while primed according to two perceptional strategies (levels: analytical vs. kinesthetic engagement), according to a within-subject design. The ranking test consisted out of wheat and rocket lettuce crystallization images, exhibiting four levels of induced degradation. The Perceptual Strategy imbuing kinesthetic engagement improved the performance of the ranking test in both samples tested. To the best of our knowledge, this is the first report on the training and application of such a Perceptual Strategy in visual evaluation.