Representational pseudoneglect in line bisection

"Representational pseudoneglect" refers to a bias toward the left side of space that occurs when visual information is remembered. Recently a number of demonstrations of such representational pseudoneglect have appeared. In the present article, we report an experiment in which we adopted the classic line bisection paradigm to study representational pseudoneglect. Participants bisected horizontal lines that were shown in extrapersonal space. When the lines were visible on the screen, there was no evidence of any leftward bias. However, when lines were bisected from memory, the participants demonstrated a clear bias to the left. This is the first demonstration of a leftward bias in the bisection of remembered visually presented lines.     

Age-related changes in visual pseudoneglect

Pseudoneglect is a slight but consistent leftward attentional bias commonly observed in healthy young populations, purportedly explained by right hemispheric dominance. It has been suggested that normal aging might be associated with a decline of the right hemisphere. According to this hypothesis, a few studies have shown that elderly tend to exhibit a rightward attentional bias in line bisection. In the present study, we tested this hypothesis in young and older participants using a perceptual landmark task. Results yield evidence for an age-related shift, from a strong attentional leftward bias in young adults toward a suppressed or even a reversed bias in the elderly. Right hemisphere impairment coupled to a left hemispheric compensation might explain the perceptual shift observed in older adults. However, a decline in corpus callosum function cannot be excluded. Alternatively, these results may be in agreement with the hypothesis of an age-related specific inhibition of return dysfunction, an overt attentional orienting mechanism, and/or a decrease of dopamine.     

Lemurs and macaques show similar numerical sensitivity

We investigated the precision of the approximate number system (ANS) in three lemur species (Lemur catta, Eulemur mongoz, and Eulemur macaco flavifrons), one Old World monkey species (Macaca mulatta) and humans (Homo sapiens). In Experiment 1, four individuals of each nonhuman primate species were trained to select the numerically larger of two visual arrays on a touchscreen. We estimated numerical acuity by modeling Weber fractions (w) and found quantitatively equivalent performance among all four nonhuman primate species. In Experiment 2, we tested adult humans in a similar procedure, and they outperformed the four nonhuman species but showed qualitatively similar performance. These results indicate that the ANS is conserved over the primate order.     

Horizontal and vertical pseudoneglect in peri- and extrapersonal space

The present study investigates the influence of depth on pseudoneglect in healthy young participants (n = 18) within three-dimensional virtual space, by presenting a variation of the greyscales task and a landmark task, which were specifically matched for stimulus–response compatibility, as well as perceptual factors within and across the tasks. Tasks were presented in different depth locations (peripersonal, extrapersonal) and different orientations (horizontal, vertical) within three-dimensional virtual space, using virtual reality technique. A horizontal leftward bias (pseudoneglect) for both tasks was found, which was stronger in peripersonal than in extrapersonal space. For the vertical condition, an upward bias was observed in the greyscales task, but not in the landmark task. These results support the hypotheses of right hemispheric dominance for visual spatial attention and our study is the first to examine horizontal and vertical orienting biases with the greyscales task in peri- and extrapersonal space. Furthermore, the differences in attentional asymmetries with respect to depth suggest dissociable neural mechanisms for visual attentional processing in near and far space and the lack of significant correlations implies independence of horizontal and vertical stimulus processing.     

Sensory and motor aspects of pseudoneglect, hemifield, and hemispace in the tactile modality

Two experiments were conducted with right-handed adult subjects to investigate motor and sensory components of a tactual line bisection task performed under three conditions: at midline, in the left, and in the right hemispaces. In the sensory experiment we found a left-hand rather than a right-hand superiority under the midline condition and, in the motor experiment, a right-hand rather than a left-hand superiority. The results were discussed with respect to hemispheric specialization and hemispace theories. Furthermore, we found a pseudoneglect (subjects bisected to the left of the midpoint) in the sensory experiment and a surprising reversed pseudoneglect (subjects bisected to the right of the midpoint) in the motor experiment.     

Duration perception in crossmodally-defined intervals

How humans perform duration judgments with multisensory stimuli is an ongoing debate. Here, we investigated how sub-second duration judgments are achieved by asking participants to compare the duration of a continuous sound to the duration of an empty interval in which onset and offset were marked by signals of different modalities using all combinations of visual, auditory and tactile stimuli. The pattern of perceived durations across five stimulus durations (ranging from 100 ms to 900 ms) follows the Vierordt Law. Furthermore, intervals with a sound as onset (audio-visual, audio-tactile) are perceived longer than intervals with a sound as offset. No modality ordering effect is found for visualtactile intervals. To infer whether a single modality-independent or multiple modality-dependent time-keeping mechanisms exist we tested whether perceived duration follows a summative or a multiplicative distortion pattern by fitting a model to all modality combinations and durations. The results confirm that perceived duration depends on sensory latency (summative distortion). Instead, we did not find evidence for multiplicative distortions. The results of the model and the behavioural data support the concept of a single time-keeping mechanism that allows for judgments of durations marked by multisensory stimuli.     

信神疑鬼酿灾祸

2004年2月15日下午2时15分,浙江省海宁市黄湾镇五丰村发生一起因群众自发迷信活动引发的特大火灾,40人命丧黄泉。 因从事迷信活动酿成特大火灾,竟然夺走40条人命,堪称迷信活动危害之最了。海宁特大火灾事故的发生深深震撼了我的心灵,促使我提笔撷取了几起近年来发生于我国各地因愚昧迷信酿成灾祸的例子,以期提高人民群众对封建迷信危害性的认识,提高警惕性,防患于未然。     

Using confidence intervals in within-subject designs

We argue that to best comprehend many data sets, plotting judiciously selected sample statistics with associated confidence intervals can usefully supplement, or even replace, standard hypothesis-testing procedures. We note that most social science statistics textbooks limit discussion of confidence intervals to their use in between-subject designs. Our central purpose in this article is to describe how to compute an analogous confidence interval that can be used in within-subject designs. This confidence interval rests on the reasoning that because between-subject variance typically plays no role in statistical analyses of within-subject designs, it can legitimately be ignored; hence, an appropriate confidence interval can be based on the standard within-subject error term—that is, on the variability due to the subject × condition interaction. Computation of such a confidence interval is simple and is embodied in Equation 2 on p. 482 of this article. This confidence interval has two useful properties. First, it is based on the same error term as is the corresponding analysis of variance, and hence leads to comparable conclusions. Second, it is related by a known factor (√2) to a confidence interval of the difference between sample means; accordingly, it can be used to infer the faith one can put in some pattern of sample means as a reflection of the underlying pattern of population means. These two properties correspond to analogous properties of the more widely used between-subject confidence interval.     

Seeing wrath from the top (through stratified lenses): Perceivers high in social dominance orientation show superior anger identification for high-status individuals

In this research, we test the hypothesis that social status will be an orienting cue to the identification of facial expressions of emotion, particularly angry expressions, especially for those who dispositionally believe that some societal groups should dominate others (Social dominance orientation; Pratto, Sidanius, Stallworth, & Malle, 1994). Using an emotion identification task, the expression of anger was identified with greater accuracy on high-status faces than low-status faces, but only for people who endorsed rigid social hierarchies (i.e., high SDO). Furthermore, people who did not endorse social hierarchies (i.e., low SDO) did not show a preference for high-status anger. Thus, the current findings provide a novel account of how social status can be an informative cue to the expression of anger in online perceptions, especially for those who view social dominance as an important framework for society.     

The Occipital Cortex in the Blind

ABSTRACT— Studying the brains of blind individuals provides a unique opportunity to investigate how the brain changes and adapts in response to afferent (input) and efferent (output) demands. We discuss evidence suggesting that regions of the brain normally associated with the processing of visual information undergo remarkable dynamic change in response to blindness. These neuroplastic changes implicate not only processing carried out by the remaining senses but also higher cognitive functions such as language and memory. A strong emphasis is placed on evidence obtained from advanced neuroimaging techniques that allow researchers to identify areas of human brain activity, as well as from lesion approaches (both reversible and irreversible) to address the functional relevance and role of these activated areas. A possible mechanism and conceptual framework for these physiological and behavioral changes is proposed.     

Intertrial intervals and visual habituation in neonates

Eighteen 3-day-old human neonates were shown a 12 by 12 black-white checkerboard target for 45-sec. trials with either a 10-, 20-, or 30-sec. intertrial interval until their visual fixation time decreased to a set criterion for habituation. On subsequent recovery trials, a 2 by 2 black-white checkerboard target received significantly longer fixations from boys in the 10-sec. and girls in the 20-sec. conditions. 30-sec. intervals, however, produced little habituation and recovery. The implications of these findings are discussed.     

The fallacy of placing confidence in confidence intervals

Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true parameter value in some known proportion of repeated samples, on average. The width of confidence intervals is thought to index the precision of an estimate; CIs are thought to be a guide to which parameter values are plausible or reasonable; and the confidence coefficient of the interval (e.g., 95 %) is thought to index the plausibility that the true parameter is included in the interval. We show in a number of examples that CIs do not necessarily have any of these properties, and can lead to unjustified or arbitrary inferences. For this reason, we caution against relying upon confidence interval theory to justify interval estimates, and suggest that other theories of interval estimation should be used instead.