Recognition of natural scenes from global properties: seeing the forest without representing the trees

Human observers are able to rapidly and accurately categorize natural scenes, but the representation mediating this feat is still unknown. Here we propose a framework of rapid scene categorization that does not segment a scene into objects and instead uses a vocabulary of global, ecological properties that describe spatial and functional aspects of scene space (such as navigability or mean depth). In Experiment 1, we obtained ground truth rankings on global properties for use in Experiments 2-4. To what extent do human observers use global property information when rapidly categorizing natural scenes? In Experiment 2, we found that global property resemblance was a strong predictor of both false alarm rates and reaction times in a rapid scene categorization experiment. To what extent is global property information alone a sufficient predictor of rapid natural scene categorization? In Experiment 3, we found that the performance of a classifier representing only these properties is indistinguishable from human performance in a rapid scene categorization task in terms of both accuracy and false alarms. To what extent is this high predictability unique to a global property representation? In Experiment 4, we compared two models that represent scene object information to human categorization performance and found that these models had lower fidelity at representing the patterns of performance than the global property model. These results provide support for the hypothesis that rapid categorization of natural scenes may not be mediated primarily though objects and parts, but also through global properties of structure and affordance.     

Resource-dependent effects during sex categorization

The limited capacity of face perception resources in the left cerebral hemisphere was examined using a sex categorization task. One study tested the hypothesis that sex categorization is impeded whenever feature extraction resources in the left hemisphere are simultaneously being utilized by another task. This hypothesis was tested by presenting prime faces for either 32 ms or 320 ms to either the left or right visual-field just before centrally presented target faces were categorized by sex. Results showed that sex categorization was slower after prime faces were presented for 32 ms in the right visual-field compared to the left visual-field. This difference was not found after the 320 ms prime length. The results are interpreted in the context of a neurocognitive model of social perception and suggest that efficient sex categorization depends, in part, on the availability of facial feature extraction resources in the left hemisphere.     

Relationships between language structure and language learning: the suffixing preference and grammatical categorization

It is a reasonable assumption that universal properties of natural languages are not accidental. They occur either because they are underwritten by genetic code, because they assist in language processing or language learning, or due to some combination of the two. In this paper we investigate one such language universal: the suffixing preference across the world's languages, whereby inflections tend to be added to the end of words. A corpus analysis of child-directed speech in English found that suffixes were more accurate at cuing the grammatical category of the root word than were prefixes. An artificial language experiment found that there was a learning advantage for suffixes over prefixes in terms of grammatical categorization within an artificial language. The results are consistent with an account of language universals that originate in general purpose learning mechanisms.     

The Complex Interplay Between Trait Fatigue and Cognition in Multiple Sclerosis

Cognitive impairments are frequent in patients with Multiple Sclerosis (MS). Yet, the influence of MS-related symptoms on cognitive status is not clear. Studies investigating the impact of trait fatigue along with anxio-depressive symptoms on cognition are seldom, and even less considered fatigue as multidimensional. Moreover, these studies provided conflicting results.Twenty-nine MS patients and 28 healthy controls, matched on age, gender and education underwent a full comprehensive neuropsychological assessment. Anxio-depressive and fatigue symptoms were assessed using the HAD scale and the MFIS, respectively. Six composite scores were derived from the neuropsychological assessment, reflecting the cognitive domains of working memory, verbal and visual learning, executive functions, attention and processing speed. Stepwise regression analyses were conducted in each group to investigate if trait cognitive and physical fatigue, depression and anxiety are relevant predictors of performance in each cognitive domain. In order to control for disease progression, patient’s EDSS score was also entered as predictor variable.In the MS group, trait physical fatigue was the only significant predictor of working memory score. Cognitive fatigue was a predictor for executive functioning performance and for processing speed (as well as EDSS score for processing speed). In the healthy controls group, only an association between executive functioning and depression was observed.Fatigue predicted cognition in MS patients only, beyond anxio-depressive symptoms and disease progression. Considering fatigue as a multidimensional symptom is paramount to better understand its association with cognition, as physical and cognitive fatigue are predictors of different cognitive processes.     

The role of exemplar distribution in infants'' differentiation of categories

Three experiments investigated how the frequency of exposure to particular exemplars influenced 10-month-old infants' differentiation of land and sea animals in an object-examining task. In Experiments 1 and 2, one category exemplar was presented more frequently than the others during familiarization (i.e., that exemplar was presented on 6 of 12 familiarization trials, and 3 other exemplars were each presented on 2 familiarization trials). For half of the infants, the frequent exemplar was similar to other category exemplars (e.g., a zebra if the familiarization category was land animals), and for half the frequent exemplar was not similar to many other category exemplars (e.g., a rabbit). Infants who frequently experienced the similar exemplar formed an exclusive category, and differentiated land and sea animals. Infants who frequently experienced a dissimilar exemplar, in contrast, formed an inclusive category, and failed to differentiate between land and sea animals. In Experiment 3, infants received frequent experience with a set of similar or dissimilar exemplars, and the same pattern was observed. Thus, 10-month-old infants are sensitive to the distribution of the exemplars to which they are exposed, and they form different category boundaries depending on that distribution.     

P-technique factor analyses of the Multiple Affect Adjective Check List (MAACL)

The Multiple Affect Adjective Check List (MAACL) has been found to have five first-order factors representing Anxiety, Depression, Hostility, Positive Affect, and Sensation Seeking and two second-order factors representing Positive Affect and Sensation Seeking (PASS) and Dysphoria. The present study examines whether these first- and second-order conceptions of affect (based on R-technique factor analysis) can also account for patterns of intraindividual variability in affect (based on P-technique factor analysis) in eight elderly women. Although the hypothesized five-factor model of affect was not testable in all of the present P-technique datasets, the results were consistent with this interindividual model of affect. Moreover, evidence of second-order (PASS and Dysphoria) and third-order (generalized distress) factors was found in one data set. Sufficient convergence in findings between the present P-technique research and prior R-technique research suggests that the MAACL is robust in describing both inter- and intraindividual components of affect in elderly women.This paper is based on the doctoral research of the first author and was partially supported by the National Institute of Aging Grant T32 AC 00048-12 to The Pennsylvania State University and a Grant-in-Aid of Research from Sigma Xi, The Scientific Research Society. The authors wish to thank John R. Nesselroade for his helpful comments on an early draft of this paper.     

Discriminant validity of the Multiple Affect Adjective Check List - revised

Four groups of patients (depressives, schizophrenics, substance dependents and abusers), a miscellaneous group of other patients, and a group of matched normals from a general population sample were compared on the scales of the Multiple Affect Adjective Check List - Revised (MAACL-R). All scales showed highly significant differentiation among the groups. An index consisting of Depression minus Positive Affect scales was particularly effective in discriminating between depressive and other groups. A discriminant function analysis showed that the depressive could be distinguished from other patient groups and normals with an accuracy of 72% correct. The normals could be distinguished from all of the patient groups with a 60% accuracy, and 87% if the substance abuser group is ignored. The discriminant validity among the nondepressive patient groups was not nearly as good.     

Enumeration versus multiple object tracking: the case of action video game players

Here, we demonstrate that action video game play enhances subjects' ability in two tasks thought to indicate the number of items that can be apprehended. Using an enumeration task, in which participants have to determine the number of quickly flashed squares, accuracy measures showed a near ceiling performance for low numerosities and a sharp drop in performance once a critical number of squares was reached. Importantly, this critical number was higher by about two items in video game players (VGPs) than in non-video game players (NVGPs). A following control study indicated that this improvement was not due to an enhanced ability to instantly apprehend the numerosity of the display, a process known as subitizing, but rather due to an enhancement in the slower more serial process of counting. To confirm that video game play facilitates the processing of multiple objects at once, we compared VGPs and NVGPs on the multiple object tracking task (MOT), which requires the allocation of attention to several items over time. VGPs were able to successfully track approximately two more items than NVGPs. Furthermore, NVGPs trained on an action video game established the causal effect of game playing in the enhanced performance on the two tasks. Together, these studies confirm the view that playing action video games enhances the number of objects that can be apprehended and suggest that this enhancement is mediated by changes in visual short-term memory skills.     

Naming and categorization in young children: III. Vocal tact training and transfer of function

Following pretraining with everyday objects, 10 children aged from 1 to 4 years were given common vocal tact training with a set of three pairs of arbitrary stimuli of differing shapes; Set 1. Nine children learned to tact one stimulus as "zog" and the other as "vek" in each pair, and all passed subsequent pairwise tests for the corresponding listener behavior to each listener stimulus (i.e., /zog/ and /vek/, respectively). The children were next trained to clap to one stimulus of Pair 1 and wave to the other, and all then showed name-consistent transfer of these behaviors to the stimuli of Pair 2 and Pair 3. Seven children also were given a test of listener responding to experimenter-modeled clap and wave gestures, respectively, which they all passed. Four of the children next participated in a category match-to-sample test for the Set 1 stimuli; all 4 passed. For each pair of two additional six-stimuli sets, Set 2 and Set 3, 3 children were trained to wave to one stimulus and to clap to the other. For each set, all 3 children showed perfect transfer of the vocal tacts trained to Set 1, and of listener behavior both to the auditory stimuli /zog/ and /vek/ and to experimenter-modeled clap and wave gestures. They also sorted the stimuli perfectly in category match-to-sample tests for Set 2, Sets 1 and 2 combined, Set 3, and Sets 1, 2, and 3 combined. The results show that even in very young children, naming is a powerful means of generating new category relations among as many as 18 arbitrary stimuli.