Variability of the MAX and MIN Statistic: A Theory of the Quantile Spread as a Function of Sample Size

The maximum and minimum of a sample from a probability distribution are extremely important random variables in many areas of psychological theory, methodology, and statistics. For instance, the behavior of the mean of the maximum or minimum processing time, as a function of the number of component random processing times (n), has been studied extensively in an effort to identify the underlying processing architecture (e.g., Townsend & Ashby, 1983; Colonius & Vorberg, 1994). Little is known concerning how measures of variability of the maximum or minimum change with n. Here, a new measure of random variability, the quantile spread, is introduced, which possesses sufficient strength to define distributional orderings and derive a number of results concerning variability of the maximum and the minimum statistics. The quantile spread ordering may be useful in many venues. Several interesting open problems are pointed out. This work was supported by an NIH Grant R01 MH57717 to the first author. Some of the collaboration took place during the year 2000 while J.T. Townsend was a Fellow at the Hanse Institute for Advanced Study (HWK), sponsored by H. Colonius at Oldenburg University.     

Spoken Idiom Recognition: Meaning Retrieval and Word Expectancy

This study investigates recognition of spoken idioms occurring in neutral contexts. Experiment 1 showed that both predictable and non-predictable idiom meanings are available at string offset. Yet, only predictable idiom meanings are active halfway through a string and remain active after the string’s literal conclusion. Experiment 2 showed that the initial fragment of a predictable idiom inhibits recognition of a word providing a congruous, but literal, conclusion to the expression. No comparable effects were obtained with non-predictable idioms. These findings are consistent with the view that spoken idiom identification differs from word recognition and occurs word-by-word, just as with other familiar, multi-lexical phrases.The present study was supported by PRIN 2003–2004. We would like to thank Corrado Cavallero, Simona Collina, Melinda Tucker and Francesco Zardon for their valuable help.     

Processing coordinated structures: incrementality and connectedness

We recorded participants' eye movements while they read sentences containing verb-phrase coordination. Results showed evidence of immediate processing disruption when a reflexive pronoun embedded in the conjoined verb phrase mismatched the sentence subject. We argue that this result is incompatible with models of human parsing that employ only bottom-up parsing procedures, even when flexible constituency is employed. Models need to incorporate a mechanism similar to the adjoining operation in Tree-Adjoining Grammar, in which one structure is inserted into another.     

Doctor's Expertise and Managing Discrepant Information from Other Sources in Genetic Counseling: A Conversation Analytic Perspective

The study examines a recurrent interactional pattern in genetic counseling. It describes clinical geneticists' responses in situations in which clients have presented information from other sources that is potentially discrepant with information given by the doctor. The data consists of 12 video-recorded sessions of genetic counseling in Finland, and the method is conversation analysis. There are two primary ways the doctors respond: either they accept the client's information as such, but show that it is not discrepant with the doctor's information, or they reject the client's information. In the latter case they mitigate the ‘wrongness’ of the client's information. The clinical geneticists seem to be working with a dilemma: they need to find a balance between ensuring correct understanding of the information and showing respect for the expertise of others. A particularly complex case is also analyzed and reflected on.     

发展性阅读障碍者的快速命名缺陷

快速命名任务是一种需要命名多个高熟悉项目的认知任务,尤其适合用来对成因复杂的发展性阅读障碍进行研究。许多研究者使用不同类型的快速命名任务发现,发展性阅读障碍者的快速命名缺陷在眼动过程表现为中央凹和副中央凹的加工困难,在认知过程中表现为抑制能力较差等。未来的研究中应该注意到快速命名缺陷的复杂性,采用多种方法相结合的方式来探究快速命名缺陷的本质,从而建立系统性的假说。     

The Nature and Significance of Behavioural Genetic Information

In light of the human genome project, establishing the genetic aetiology of complex human diseases has become a research priority within Western medicine. However, in addition to the identification of disease genes, numerous research projects are also being undertaken to identify genes contributing to the development of human behavioural characteristics, such as cognitive ability and criminal tendency. The permissibility of this research is obviously controversial: will society benefit from this research, or will it adversely affect our conceptions of ourselves and each other? When assessing the permissibility of this research, it is important to consider the nature and deterministic significance of behavioural genetic information. Whilst todate there has been much discussion and debate about the properties of genetic information per se and genetic determinism, this has not been applied to behavioural genetic research and its ethical implications. Therefore, this paper elucidates how behavioural genetic information can be distinguished from other types of genetic and non-genetic information and also synthesises the determinative significance of genetic factors for the development of human behavioural traits. Undertaking this analysis enables the ethical issues raised by this research to be debated in an appropriate context and indicates that separate policy considerations are warranted.

     

Changes in the structure of children's isometric force variability with practice

This study examined the effect of age and practice on the structure of children's force variability to test the information processing hypothesis that a reduction of sensorimotor system noise accounts in large part for age-related reductions in perceptual-motor performance variability. In the study, 6-year-olds, 10-year-olds, and young adults practiced on 5 consecutive days (15 trials/day), maintaining for 15-s trials a constant level of force (5 or 25% of maximum voluntary contraction) against an object using a pinch grip (thumb and index finger). With increasing age, the amount of force error and variability decreased, but the sequential structure of variability increased in irregularity. With practice, children reduced the amount of variability by changing the structure of the force output so as to be more similar to that of their older counterparts. The findings provide further evidence that practice-driven changes in the structure of force output, rather than a decline in the amount of white noise, largely account for age-related reductions in the amount of force variability.     

Why 8-year-olds cannot tell the difference between Steve Martin and Paul Newman: factors contributing to the slow development of sensitivity to the spacing of facial features

Children are nearly as sensitive as adults to some cues to facial identity (e.g., differences in the shape of internal features and the external contour), but children are much less sensitive to small differences in the spacing of facial features. To identify factors that contribute to this pattern, we compared 8-year-olds' sensitivity to spacing cues with that of adults under a variety of conditions. In the first two experiments, participants made same/different judgments about faces differing only in the spacing of facial features, with the variations being kept within natural limits. To measure the effect of attention, we reduced the salience of featural information by blurring faces and occluding features (Experiment 1). To measure the role of encoding speed and memory limitations, we presented pairs of faces simultaneously and for an unlimited time (Experiment 2). To determine whether participants' sensitivity would increase when spacing distortions were so extreme as to make the faces grotesque, we manipulated the spacing of features beyond normal limits and asked participants to rate each face on a "bizarreness" scale (Experiment 3). The results from the three experiments indicate that low salience, poor encoding efficiency, and limited memory can partially account for 8-year-olds' poor performance on face processing tasks that require sensitivity to the spacing of features, a kind of configural processing that underlies adults' expertise. However, even when the task is modified to compensate for these problems, children remain less sensitive than adults to the spacing of features.     

Infants' comprehension of toy replicas as symbols for real objects

Infants' understanding of toy model-real exemplar relations was assessed through preferential looking and habituation tasks. Results from the preferential looking task suggest that 18-month toddlers are just beginning to demonstrate comprehension of symbolic relations between iconic models and their real object counterparts. Performance of 10- and 14-month-old infants in the preferential looking task did not improve when across-domain pairs of videos were used in place of within-domain pairs. Habituation task results indicated that 10-month-olds do not comprehend symbolic relations between miniature toy replicas and their "real" counterparts, but that such understanding begins to emerge by age 14 months. Interactions between symbolic processing and early lexical development are considered, as are methodological implications for the study of infant categorization.     

Seeing to hear better: evidence for early audio-visual interactions in speech identification

Lip reading is the ability to partially understand speech by looking at the speaker's lips. It improves the intelligibility of speech in noise when audio-visual perception is compared with audio-only perception. A recent set of experiments showed that seeing the speaker's lips also enhances sensitivity to acoustic information, decreasing the auditory detection threshold of speech embedded in noise [J. Acoust. Soc. Am. 109 (2001) 2272; J. Acoust. Soc. Am. 108 (2000) 1197]. However, detection is different from comprehension, and it remains to be seen whether improved sensitivity also results in an intelligibility gain in audio-visual speech perception. In this work, we use an original paradigm to show that seeing the speaker's lips enables the listener to hear better and hence to understand better. The audio-visual stimuli used here could not be differentiated by lip reading per se since they contained exactly the same lip gesture matched with different compatible speech sounds. Nevertheless, the noise-masked stimuli were more intelligible in the audio-visual condition than in the audio-only condition due to the contribution of visual information to the extraction of acoustic cues. Replacing the lip gesture by a non-speech visual input with exactly the same time course, providing the same temporal cues for extraction, removed the intelligibility benefit. This early contribution to audio-visual speech identification is discussed in relationships with recent neurophysiological data on audio-visual perception.