Curvature-specific color aftereffects

Adaptation to convex and concave arcs in different colored light results in curvature-specific color aftereffects when arcs are later viewed in white light. In three experiments, it was shown that these color aftereffects often are partial (restricted to limited regions of the test arcs) rather than uniform, and in addition that aftereffects induced by exposure to arcs transfer to straight-line displays of particular orientation, and vice versa. These data were interpreted as evidence that arcs are processed in the visual system in relation to the orientations of local straight line approximations instead of on a global basis. In these terms, curvature-specific color aftereffects are merely complex forms of the orientation-specific color aftereffects first described by McCollough (1965).     

Orientation-specific aftereffects and illusions in the perception of brightness

Orientation-specific brightness aftereffects were found when vertical and horizontal gratings of the same space-average luminance were viewed following alternate exposure to vertical and horizontal gratings that differed in space-average luminance. The vertical test grating appeared bright following exposure to a dim vertical grating, and dim after a bright vertical grating had been viewed. This aftereffect did not occur when the adaptation gratings had been seen by one eye and the test gratings by the other eye. An orientation-specific illusion in the perception of brightness was also found, with the white sectors of a vertical grating appearing brighter against a background of horizontal lines than they did against a background of vertical lines. Both distortions imply that there are detectors in the human visual system that are conjointly tuned to luminance and contour orientation.     

Spatial-frequency-contingent color aftereffects: Adaptation with two-dimensional stimulus patterns

The spatial-frequency theory of vision has been supported by adaptation studies using checkerboards in which contingent color aftereffects (CAEs) were produced at fundamental frequencies oriented at 45\dg to the edges. A replication of this study failed to produce CAEs at the orientation of either the edges or the fundamentals. Using a computer-generated display, no CAEs were produced by adaptation of a square or an oblique checkerboard. But when one type of checkerboard (4 cpd) was adapted alone, CAEs were produced on the adapted checkerboard and on sine-wave gratings aligned with the fundamental and third harmonics of the checkerboard spectrum. Adaptation of a coarser checkerboard (0.80 cpd) produced CAEs aligned with both the edges and the harmonic frequencies. With checkerboards of both frequencies, CAEs were also found on the other type of checkerboard that had not been adapted. This observation raises problems for any edge-detector theory of vision, because there was no adaptation to edges. It was concluded that spatial-frequency mechanisms are operating at both low- and high-spatial frequencies and that an edge mechanism is operative at lower frequencies. The implications of these results are assessed for other theories of spatial vision.     

How extraverted is honey.bunny77@hotmail.de? Inferring personality from e-mail addresses

Computer mediated communication (CMC) plays a rapidly growing role in our social lives. Within this domain, e-mail addresses represent the thinnest slice of information that people receive from one another. Using 599 e-mail addresses of young adults, their self-reported personality scores and the personality judgments of 100 independent observers, it was shown that personality impressions based solely on e-mail addresses were consensually shared by observers. Moreover, these impressions contained some degree of validity. This was true for neuroticism, openness, agreeableness, conscientiousness, and narcissism but not for extraversion. Level of accuracy was explained using lens model analyses: Lay observers made broad use of perceivable e-mail address features in their personality judgments, features were slightly valid and observers were sensitive to subtle differences in validity between cues. Altogether, even the thinnest slice of CMC—the mere e-mail address—contains valid information about the personality of its owner.     

A cross‐cultural investigation into a reconceptualization of ethnocentrism

This investigation tests a reconceptualization of ethnocentrism based primarily on Sumner's definitions. Ethnocentrism is reconceptualized as ethnic group self‐centeredness, with four intergroup expressions of ingroup preference, superiority, purity, and exploitativeness, and two intragroup expressions of group cohesion and devotion. The reconceptualization was supported in Study 1 among 350 New Zealand participants and in Study 2 among 212 US, 208 Serbian, and 279 French participants. Ethnocentrism in each country consisted of two correlated second‐order factors representing intergroup and intragroup ethnocentrism and six first‐order factors representing the six primary expressions. Analyses in Study 2 supported the measurement invariance of the scale and a third‐order factor model, with one ethnocentrism factor at the broadest level of generalization. Ethnocentrism was empirically distinct from outgroup negativity and mere ingroup positivity. Intragroup ethnocentrism appeared primarily based on ethnic insecurity, personal self‐transcendence, and ethnic identification, whereas intergroup ethnocentrism appeared primarily based on self‐aggrandizement, warlikeness, and generally chauvinistic attitudes. Accordingly, although related, the two kinds of ethnocentrism tend to have quite differential implications for group attitudes and behaviors. Copyright © 2008 John Wiley & Sons, Ltd. This article was published online on 31 December 2008. Errors were subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected [date to be added later].     

Speech perception engages a general timer: Evidence from a divided attention word identification task

Time is essential to speech. The duration of speech segments plays a critical role in the perceptual identification of these segments, and therefore in that of spoken words. Here, using a French word identification task, we show that vowels are perceived as shorter when attention is divided between two tasks, as compared to a single task control condition. This temporal underestimation pattern is consistent with attentional models of timing and hence demonstrates that vowel duration is explicitly estimated using a central general-purpose timer.     

Sequential adjustments before and after partial errors

In choice reaction time tasks, subjects speed up before making an error, but slow down afterward to prevent the occurrence of a new error. In some trials, the correct response is preceded by an incorrect electromyographic (EMG) activation too small to reach the response threshold. In this article, we show that these incorrect EMG activations give rise to the same sequential effects as overt errors: Before a trial containing an incorrect EMG activation, subjects speed up, whereas after that trial, they slow down. These activations reflect errors that have been detected, inhibited, and corrected in time. As such, they index the involvement of online executive control.     

Moving beyond Kučera and Francis: A critical evaluation of current word frequency norms and the introduction of a new and improved word frequency measure for American English

Word frequency is the most important variable in research on word processing and memory. Yet, the main criterion for selecting word frequency norms has been the availability of the measure, rather than its quality. As a result, much research is still based on the old Kučera and Francis frequency norms. By using the lexical decision times of recently published megastudies, we show how bad this measure is and what must be done to improve it. In particular, we investigated the size of the corpus, the language register on which the corpus is based, and the definition of the frequency measure. We observed that corpus size is of practical importance for small sizes (depending on the frequency of the word), but not for sizes above 16–30 million words. As for the language register, we found that frequencies based on television and film subtitles are better than frequencies based on written sources, certainly for the monosyllabic and bisyllabic words used in psycholinguistic research. Finally, we found that lemma frequencies are not superior to word form frequencies in English and that a measure of contextual diversity is better than a measure based on raw frequency of occurrence. Part of the superiority of the latter is due to the words that are frequently used as names. Assembling a new frequency norm on the basis of these considerations turned out to predict word processing times much better than did the existing norms (including Kučera & Francis and Celex). The new SUBTL frequency norms from the SUBTLEXUS corpus are freely available for research purposes from http://brm.psychonomic-journals.org/content/supplemental, as well as from the University of Ghent and Lexique Web sites.