How active perception and attractor dynamics shape perceptual categorization: A computational model

We propose a computational model of perceptual categorization that fuses elements of grounded and sensorimotor theories of cognition with dynamic models of decision-making. We assume that category information consists in anticipated patterns of agent–environment interactions that can be elicited through overt or covert (simulated) eye movements, object manipulation, etc. This information is firstly encoded when category information is acquired, and then re-enacted during perceptual categorization. The perceptual categorization consists in a dynamic competition between attractors that encode the sensorimotor patterns typical of each category; action prediction success counts as ‘‘evidence’’ for a given category and contributes to falling into the corresponding attractor. The evidence accumulation process is guided by an active perception loop, and the active exploration of objects (e.g., visual exploration) aims at eliciting expected sensorimotor patterns that count as evidence for the object category. We present a computational model incorporating these elements and describing action prediction, active perception, and attractor dynamics as key elements of perceptual categorizations. We test the model in three simulated perceptual categorization tasks, and we discuss its relevance for grounded and sensorimotor theories of cognition.Peer reviewe

Too little, too late: reduced visual span and speed characterize pure alexia

Whether normal word reading includes a stage of visual processing selectively dedicated to word or letter recognition is highly debated. Characterizing pure alexia, a seemingly selective disorder of reading, has been central to this debate. Two main theories claim either that 1) Pure alexia is caused by damage to a reading specific brain region in the left fusiform gyrus or 2) Pure alexia results from a general visual impairment that may particularly affect simultaneous processing of multiple items. We tested these competing theories in 4 patients with pure alexia using sensitive psychophysical measures and mathematical modeling. Recognition of single letters and digits in the central visual field was impaired in all patients. Visual apprehension span was also reduced for both letters and digits in all patients. The only cortical region lesioned across all 4 patients was the left fusiform gyrus, indicating that this region subserves a function broader than letter or word identification. We suggest that a seemingly pure disorder of reading can arise due to a general reduction of visual speed and span, and explain why this has a disproportionate impact on word reading while recognition of other visual stimuli are less obviously affected

The Influence of Warning Label Presentation in Memory Recognition of Aging Adults

Research indicates that hundreds of thousands of people are injured each year as a result of poor communication between medical personnel, warning label information, and consumers when taking over the counter or prescription medication. Typically, as adult\u27s age, they are increasingly responsible for remembering the hazards of taking medications. If inadequate information exists in memory in regards to side effects, dosage, and other warnings, the likelihood of improper usage will increase. Because aging adults typically have a reduction in cognitive resources, it was hypothesized that older adults would require the aid of additional warning information to assist in the retrieval process of this information. Therefore, it was predicted that aging adults will be able to retrieve information at a better performance level with a redundant set of text and pictorial information as it relates to warning labels than younger adults

Parting A Read Sea Of Images: An Exploration Of Field Dependent-Independent Responses To Minimalist, Pictographic And Infographic Data Displays

ABSTRACT Western society reflects an âeikoncentric eraâ when contemporary instruction has become image -centered. Textbooks, journals, popular media as well as computer-based and web- based instructional media are filled by pictures that are intended to accomplish learning. Imagery is widely believed to represent an efficient, understandable method for relaying information and clarifying instruction for nearly all learners. However, those who subscribe to the adage âa picture is worth a thousand wordsâ often fail to acknowledge individual differences in visual comprehension and cognition. The field dependent-independent (FDI) cognitive style describes individual learner differences that can thwart visual learning. Information graphics are among the frequently used types of imagery that portray data. There is little empirical evidence to guide their design, and their creation is often based on intuition or opinion. This study researched the ways FDI learners comprehend and aesthetically assess minimalist information graphics, pictograms and infographics. Those participants who represented the most extreme field-dependent or field-independent learners were invited to participate in a two-part study. An instrument named the Comparative Information Graphic Test (CIG-T) was developed for testing comprehension of and perceived aesthetic efficacy, value and preference for minimalist information graphics, pictograms and infographics by FDI learner

Genetic Mechanisms of Telencephalon Diversification Through Shifts in the Pallial-Subpallial Boundary

The vertebrate brain develops through the formation of compartments. These compartments are physically separated to allow for the proper differentiation of each structure within the brain. The telencephalon, a compartment analogous to the cerebral cortex of mammals, further subdivides once it is separated from the rest of the developing forebrain. The first division within the telencephalon splits it into the ventral and dorsal divisions, or the subpallial and pallial regions, respectively. The pallial-subpallial boundary (PSB) separates these regions to ensure proper development of each telencephalic structure. The pallium develops into memory storage and processing centers, and the subpallium further divides into the pallidum and the olfactory bulbs, which are involved in motor coordination and scent processing, respectively. Because of the different ecological niches occupied by cichlid species, they utilize certain telencephalic structures moreso than others and because of the space constraints, telencephalic morphology reflects these preferences. Mbuna species, which feed among the rocks scraping algae, utilize their sense of smell and have large olfactory bulbs. Non-mbuna species, which feed in the water column and utilize eyesight and possibly memory for recognition of prey, have larger pallial structures. These differences in structures are observed early in development shortly after the telencephalon separates from the remainder of the forebrain. Upon formation of the PSB, placement and angle of the boundary are distinctly different in mbuna and non-mbuna species. In mbuna species compared to non-mbuna species, the PSB is shifted dorsally, allowing more tissue to be allocated to the developing olfactory bulbs. The PSB is shifted ventrally in nonmbuna species to allocate more tissue to the progenitor cells that develop into the memoryx processing center and structures that process visual input. These observed shifts in the developmental boundaries within the brain may provide insight into the evolution of structures such as the cerebral cortex.Streelman, Todd - Faculty Mento

Repetition blindness and bilingual memory: Token individuation for translation equivalents

The repetition blindness effect (RB) occurs when individuals are unable to recall a repeated word relative to a nonrepeated word in a sentence or string of words presented in a rapid serial visual presentation task. This effect was explored across languages (English and Spanish) in an attempt to provide evidence for RB at a conceptual level using noncognate translation equivalents (e.g.,nephew-sobrino). In the first experiment, RB was found when a word was repeated in an English sentence but not when the two repetitions were in different languages. In the second experiment, RB was found for identical repetitions in Spanish and in English using word lists. However, the crosslanguage condition produced significant facilitation in recall, suggesting that although conceptual processing had taken place, semantic overlap was not sufficient to produce RB. The results confirm Kanwisher’s (1987) token individuation hypothesis in the case of translation equivalent

Scientific Visualization Using the Flow Analysis Software Toolkit (FAST)

Over the past few years the Flow Analysis Software Toolkit (FAST) has matured into a useful tool for visualizing and analyzing scientific data on high-performance graphics workstations. Originally designed for visualizing the results of fluid dynamics research, FAST has demonstrated its flexibility by being used in several other areas of scientific research. These research areas include earth and space sciences, acid rain and ozone modelling, and automotive design, just to name a few. This paper describes the current status of FAST, including the basic concepts, architecture, existing functionality and features, and some of the known applications for which FAST is being used. A few of the applications, by both NASA and non-NASA agencies, are outlined in more detail. Described in the Outlines are the goals of each visualization project, the techniques or 'tricks' used lo produce the desired results, and custom modifications to FAST, if any, done to further enhance the analysis. Some of the future directions for FAST are also described

Looking at the Lanham Act: Images in Trademark and Advertising Law

Words are the prototypical regulatory subjects for trademark and advertising law, despite our increasingly audiovisual economy. This word-focused baseline means that the Lanham Act often misconceives its object, resulting in confusion and incoherence. This Article explores some of the ways courts have attempted to fit images into a word-centric model, while not fully recognizing the particular ways in which images make meaning in trademark and other forms of advertising. While problems interpreting images are likely to persist, this Article suggests some ways in which courts could pay closer attention to the special features of images as compared to words

2D Grammar Extension of the CMP Mathematical Formulae On-line Recognition System

Projecte realitzat en col.laboració amb Czech Technical University in PragueIn the last years, the recognition of handwritten mathematical formulae has recieved an increasing amount of attention in pattern recognition research. However, the diversity of approaches to the problem and the lack of a commercially viable system indicate that there is still much research to be done in this area. In this thesis, I will describe the previous work on a system for on-line handwritten mathematical formulae recognition based on the structural construction paradigm and two-dimensional grammars. In general, this approach can be successfully used in the anaylysis of inputs composed of objects that exhibit rich structural relations. An important benefit of the structural construction is in not treating symbols segmentation and structural anaylsis as two separate processes which allows the system to perform segmentation in the context of the whole formula structure, helping to solve arising ambiguities more reliably. We explore the opening provided by the polynomial complexity parsing algorithm and extend the grammar by many new grammar production rules which made the system useful for formulae met in the real world. We propose several grammar extensions to support a wide range of real mathematical formulae, as well as new features implemented in the application. Our current approach can recognize functions, limits, derivatives, binomial coefficients, complex numbers and more