Detection of the sign of expansion as a function of field size and eccentricity

Small optical flow fields are involved in object and shape recognition. These tasks depend on high resolution and low speed of the flow-field elements. Large optical flow fields are involved in tasks such as orientation and navigation, which require flow-field elements to move at high speed. From the above, we would expect to find different behavior of subjects for different parameter ranges of field size and speed of the elements. In this paper, we address the question of whether such different behavior exists for a task that is associated neither with object recognition nor with navigation. We obtained detection thresholds for expansion in the presence of translation for a wide range of field sizes. The same paradigm was used to investigate whether subjects made efficient use of peripheral information. We found viewing-distance invariance, meaning that subjects’ performance scaled with stimulus size. Subjects performed very similarly with and without foveal information.     

PROCESSING SPEED, WORKING MEMORY, AND FLUID INTELLIGENCE:

Abstract— Processing speed, working memory capacity, and fluid intelligence were assessed in a large sample ( N = 214) of children, adolescents, and young adults (ages 7 to 19 years) Results of path analyses revealed that almost half of the age-related increase in fluid intelligence was mediated by developmental changes in processing speed and marking memory and nearly three fourths of the improvement in working memory was mediated by developmental changes in processing speed Moreover, even when age-related differences in speed, working memory and fluid intelligence were statistically controlled, individual differences in speed had a direct effect on working memory capacity which, in turn was a direct determinant of individual differences in fluid intelligence     

Pictorial surface attitude and local depth comparisons

We measured local surface attitude for monocular pictorial relief and performed pairwise depthcomparison judgments on the same picture. Both measurements were subject to internal consistency checks. We found that both measurements were consistent with a relief (continuous pictorial surface) interpretation within the session-to-session scatter. We reconstructed the pictorial relief from both measurements separately, and found results that differed in detail but were quite similar in their basic structures. Formally, one expects certain geometrical identities that relate range and attitude data. Because we have independent measurements of both, we can attempt an empirical verification of such geometrical identities. Moreover, we can check whether the statistical scatter in the data indicates that, for example, the surface attitudes are derivable from a depth map or vice versa. We estimate that pairwise depth comparisons are an order of magnitude less precise than might be expected from the attitude data. Thus, the surface attitudes cannot be derived from a depth map as operationally defined by our methods, although the reverse is a possibility.     

Verb frequency and enactment in implicit and explicit memory

In this article we report on two experiments concerning the effects of verb frequency and enactment on explicit- and implicit-memory tests. The results showed that verb frequency and enactment had additive effects on (explicit) recognition. Moreover, an (implicit) verb-identification test showed that prior enactment had absolutely no influence on this test, while verb frequency had a clear-cut effect. These results speak in favor of the assumption that verb-frequency and enactment effects are based on different types of information. It is further assumed that the verb-frequency effect is a lexical effect, whereas the enactment effect is not.     

Problems in evaluating the real-world usability of digital voice communication systems

Digital voice communication systems are being used in a wide variety of applications. Human observers are used to measure the performance of computer voice systems. We also need to determine how losses in speech quality and intelligibility affect the performance of the communicator. This paper considers several situational variables that can affect the usability and acceptance of digital voice communication systems: task constraints, user experience, and communication environment. User experience and communication environment influence the acceptability of degraded voice systems; greater experience and field environments lead to higher acceptability ratings. However, performance measures, such as task completion time, are still adversely affected by lower voice quality.     

The role of regional heterogeneity in age-related differences in functional hemispheric asymmetry: an fMRI study

Neuroimaging literature has documented age-related hemispheric asymmetry reduction in frontal regions during task performances. As most studies employed working memory paradigms, it is therefore less clear if this pattern of neural reorganization is constrained by working memory processes or it would also emerge in other cognitive domains which are predominantly lateralized. Using blocked functional magnetic resonance imaging (fMRI), the present study used a homophone judgment task and a line judgment task to investigate age-related differences in functional hemispheric asymmetry in language and visuospatial processing respectively. Young and older adults achieved similar task accuracy although older adults required a significantly longer time. Age-related functional hemispheric asymmetry reduction was found only in dorsal inferior frontal gyrus and was associated with better performance when the homophone condition was contrasted against fixation, and not line condition. Our data thus highlights the importance of considering regional heterogeneity of aging effects together with general age-related cognitive processes.     

Exaggeration is harder than understatement, but practice makes perfect!

Previous research on the fakeability of the Implicit Association Test (IAT) yielded inconsistent results. The present study simultaneously analyses several relevant factors: faking direction, type of instructions, and practice. Furthermore, it takes baseline individual differences into account. After a baseline assessment in a self-esteem IAT without faking instructions (t0), participants in the faking conditions then (t1) faked high or low scores without being provided with recommended strategies on how to do so (i.e., individual strategies). At t2 and t3, they were asked to fake the IAT after having received information on recommended faking strategies. At t4, faking direction was reversed. Without the recommended strategies, faking high scores was not possible, but faking low scores was. With the recommended strategies, participants needed additional practice to fake high scores. When faking directions were reversed, participants were successful without additional practice, suggesting a transfer in faking skills. In most of the faking attempts, faking success was moderated by individual differences in baseline implicit self-esteem. This suggests that the complex interplay of factors influencing faking success should be taken into account when considering the issue of fakeability of the IAT.     

Colour specificity in episodic and in perceptual object recognition with enhanced colour impact

In three experiments we investigated the perceptual specificity of explicit (old-new object recognition) and implicit memory (word-picture matching) for colour. In order to enhance the impact of colour on processing, we increased the number of colours per object and we impaired shape information. We presented multicoloured pictures (Experiment 1), blurred and partially occluded pictures (Experiment 2) and coloured line drawings in visual noise (Experiment 3). Experiments 1 and 2 had an intentional study phase; the study phase of Experiment 3 was an incidental colour or category naming task. Changing colour from study to test always had negative effects on episodic recognition although colour was irrelevant. In contrast, in the matching task old pictures were generally matched faster than new ones independent of their colour congruence. In Experiment 3, an additional small advantage of congruent colours and of semantic processing occurred. We conclude that two different memory representations contribute to these tasks. Changes of an achromatic, more abstract representation, that is used in normal object recognition, and a representation of the specific exemplar that includes colour. This latter token is used in episodic recognition as well as in unusual perceptual tasks (Experiment 3).     

Episodic autobiographical memory in depression: Specificity, autonoetic consciousness, and self-perspective

Autobiographical memory (AM) and the self are closely linked. AM retrieval in depression is characterized by a lack of specificity, suggesting an impairment of episodic AM. Autonoetic consciousness and self-perspective, which are critical to episodic AM, have never been addressed in depression. Twenty-one depressed inpatients and 21 matched controls were given an episodic AM task designed to assess positive and negative memories regarding specificity, autonoetic consciousness (remember/know procedure), and self-perspective (field/observer procedure). For specificity, "remember", and "field" responses, ANOVAs revealed a main group effect and a group x valence interaction. Between groups, patients showed lower scores than controls for positive memories. Within groups, patients showed greater scores for negative memories, and controls showed greater scores for positive memories. There is a global episodic AM impairment of positive memories in depression regarding specificity, autonoetic consciousness, and self-perspective. Our results suggest new cognitive interventions to improve the self-relevance of positive memories in depression.     

The Ebbinghaus illusion modulates visual search for size-defined targets: evidence for preattentive processing of apparent object size

Five search experiments investigated whether the apparent size of objects is, like their retinal size, coded in preattentive vision. Observers searched for a target circle that was either larger or smaller than distractor circles, with both types of test circles surrounded by context circles modulating apparent size (i.e., the Ebbinghaus illusion). The size ratio between the test and the context circles was manipulated in such a way that the test circles were surrounded by, for example, smaller context circles (making the larger target appear even larger) or by larger context circles (making the smaller distractors appear even smaller). Under optimal conditions, the detection reaction times were independent of the number of test circles in the display, and the Ebbinghaus illusion facilitated the detection of the target even in comparison with control conditions without any context circles. This finding is consistent with preattentive, spatially parallel processing of apparent size.