Testing equivalence with repeated measures: tests of the difference model of two-alternative forced-choice performance

Solving theoretical or empirical issues sometimes involves establishing the equality of two variables with repeated measures. This defies the logic of null hypothesis significance testing, which aims at assessing evidence against the null hypothesis of equality, not for it. In some contexts, equivalence is assessed through regression analysis by testing for zero intercept and unit slope (or simply for unit slope in case that regression is forced through the origin). This paper shows that this approach renders highly inflated Type I error rates under the most common sampling models implied in studies of equivalence. We propose an alternative approach based on omnibus tests of equality of means and variances and in subject-by-subject analyses (where applicable), and we show that these tests have adequate Type I error rates and power. The approach is illustrated with a re-analysis of published data from a signal detection theory experiment with which several hypotheses of equivalence had been tested using only regression analysis. Some further errors and inadequacies of the original analyses are described, and further scrutiny of the data contradict the conclusions raised through inadequate application of regression analyses.     

Portuguese-Canadian Emigrant Descendents in Multicultural Canada: Ambiguous Identity in a Sure-Footed Nation or Cultural Awareness in an Uncertain Country?

This paper examines the ways the descendents of Portuguese-Canadian immigrants contemplate and formulate their identities. Through qualitative, open-ended interviews, the research demonstrates how these individuals contest ideas of ‘being Portuguese’ and ‘being Canadian’ within the frameworks of the Canadian multicultural policy. Refusing to be positioned outside the nation and Anglo/Francophone conformity, these individuals produce their own meanings of identity by working through their own personally identified multiethnic bodies to the national body politic, where some of them see their own selves as intrinsically ‘multicultural’ and contributors to the very definition of a Canadian identity. Challenging the tropes of the Canadian multicultural narrative, these descendents, thus, develop nuanced models of cultural citizenship, illustrating that national identities are formed and transformed in relation to representation. Through the process of narrative analysis, my endeavour of this article are twofold: on one hand, to illuminate the role of these individuals who, as active actors, are shaped by the social worlds they delve in and, on the other, to explicate how the roles played out by these actors can contribute to the construction of ‘a Canadian identity’.     

Speaking to the trained ear: musical expertise enhances the recognition of emotions in speech prosody

Language and music are closely related in our minds. Does musical expertise enhance the recognition of emotions in speech prosody? Forty highly trained musicians were compared with 40 musically untrained adults (controls) in the recognition of emotional prosody. For purposes of generalization, the participants were from two age groups, young (18-30 years) and middle adulthood (40-60 years). They were presented with short sentences expressing six emotions-anger, disgust, fear, happiness, sadness, surprise-and neutrality, by prosody alone. In each trial, they performed a forced-choice identification of the expressed emotion (reaction times, RTs, were collected) and an intensity judgment. General intelligence, cognitive control, and personality traits were also assessed. A robust effect of expertise was found: musicians were more accurate than controls, similarly across emotions and age groups. This effect cannot be attributed to socioeducational background, general cognitive or personality characteristics, because these did not differ between musicians and controls; perceived intensity and RTs were also similar in both groups. Furthermore, basic acoustic properties of the stimuli like fundamental frequency and duration were predictive of the participants' responses, and musicians and controls were similarly efficient in using them. Musical expertise was thus associated with cross-domain benefits to emotional prosody. These results indicate that emotional processing in music and in language engages shared resources.     

Interpersonal distance regulates functional grouping tendencies of agents in team sports

The authors examined whether, similar to collective agent behaviors in complex, biological systems (e.g., schools of fish and colonies of ants), performers in team sports displayed functional coordination tendencies, based on local interaction rules during performance. To investigate this issue, they used videogrammetry and digitizing procedures to observe interpersonal interactions in common 4 versus 2 + 2 subphases of the team sport of rugby union, involving 16 participants aged between 16 and 17 years of age. They observed pattern-forming dynamics in attacking subunits (n = 4 players) attempting to penetrate 2 defensive lines (n = 2 players in each). Data showed that within each attacking subunit, the 4 players displayed emergent functional grouping tendencies that differed between the 2 defensive lines. Results confirmed that grouping tendencies in attacking subunits of team games are sensitive to different task constraints, such as relative positioning to nearest defenders. It was concluded that running correlations were particularly useful for measuring the level of interpersonal coordination in functional grouping tendencies within attacking subunits.     

Contemporary theories of 1/f noise in motor control

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.     

Improving comprehension and communication of risks about health

Many patients have severe difficulties grasping several numerical concepts that are related to their health, such as, for instance, the risk of suffering various diseases. Visual aids have been proposed as a promising method for enhancing risk communication and comprehension. In medical practice, however, not all patients benefit from visual aids. In a study conducted on a probabilistic, representative national sample in the United States, we identified a group of patients for whom visual aids are most useful: Those who have low numeracy but high graphical literacy skills. These patients have high scores in three abilities involved in graph comprehension: (1) the ability to read the data, (2) the ability to read the relations between the data, and (3) the ability to read beyond the data. Our results can have important implications for medical practice and for risk communication about health.     

Gender and Race Portrayals on Spanish-Language Television

318 randomly selected television ads from India (from 2004) in three different languages (English, Hindi, and Tamil) were content analyzed to examine both the frequency of appearance and prevalence of gender stereotypes. Results indicate that there are more male than female central characters and voiceovers in Indian ads; stereotypical differences were also found in the type of credibility used by men and women, and the nature of the products they advertised and settings that males and females appeared in. Female central characters tended to be younger than their male counterparts and were more likely to be portrayed in relationship roles. Similarities and differences in gender role portrayals found in Indian television ads and those from other nations are also discussed.