Selecting a linear mixed model for longitudinal data: repeated measures analysis of variance, covariance pattern model, and growth curve approaches

With increasing popularity, growth curve modeling is more and more often considered as the 1st choice for analyzing longitudinal data. Although the growth curve approach is often a good choice, other modeling strategies may more directly answer questions of interest. It is common to see researchers fit growth curve models without considering alterative modeling strategies. In this article we compare 3 approaches for analyzing longitudinal data: repeated measures analysis of variance, covariance pattern models, and growth curve models. As all are members of the general linear mixed model family, they represent somewhat different assumptions about the way individuals change. These assumptions result in different patterns of covariation among the residuals around the fixed effects. In this article, we first indicate the kinds of data that are appropriately modeled by each and use real data examples to demonstrate possible problems associated with the blanket selection of the growth curve model. We then present a simulation that indicates the utility of Akaike information criterion and Bayesian information criterion in the selection of a proper residual covariance structure. The results cast doubt on the popular practice of automatically using growth curve modeling for longitudinal data without comparing the fit of different models. Finally, we provide some practical advice for assessing mean changes in the presence of correlated data.     

Prospective teachers' conceptions of assessment: a cross-cultural comparison

This paper examines the responses of two sample of prospective teachers (New Zealand, n = 324; and Spain, n = 672) to the Teachers' Conceptions of Assessment inventory (English and Spanish respectively). The inventory captures four major intentions for assessment (i.e., improvement, irrelevance, school and student accountability). The conceptions of prospective teachers about the nature and purpose of assessment are relevant, given that (a) much educational assessment is carried out in classrooms; and (b) prospective teachers enter the teacher education programs with significant prior school experience of assessment as pupils. Results of confirmatory factor analysis indicated that the original model was inadmissible and that the best-fitting revised model was only configurally invariant between the two samples. It would appear that lack of teaching experience results in different responses for prospective teachers to those of practicing teachers. Moreover, differences in societal and cultural priorities for assessment use most likely explain the lack of invariance between samples.     

Moral Machines?

Wendell Wallach and Colin Allen??s Moral Machines: Teaching Robots Right From Wrong (Oxford University Press, 2009) explores efforts to develop machines that, not only can be employed for good or bad ends, but which themselves can be held morally accountable for what they do??artificial moral agents (AMAs). This essay is a critical response to Wallach and Allen??s conjectures. Although Wallach and Allen do not suggest that we are close to being able to create full-fledged AMAs, they do talk seriously about making incremental progress in the direction of creating them (even if we never fully succeed). However, there are important questions about the moral development of AMAs that Moral Machines does not address. Given the responsibilities entrusted to human moral agents, we take questions about their moral development very seriously. In the case of children, the hope is that eventually they will develop into full-fledged moral agents. How might we expect this to go with less than fully formed AMAs? Will there be a comparable story of moral development and moral education that we can tell?     

Emotion regulation and aggression

This review considers the impact of deliberate emotion regulation on aggression, by integrating findings from recent emotion regulation research with a contemporary model of aggressive behavior, the General Aggression Model. First, it considers how individuals who under-regulate anger and other emotions may be more likely to behave aggressively in an attempt to repair, terminate, or avoid uncomfortable emotional states. Second, it explores how over-regulation of emotion may lead to aggressive behavior by increasing negative affect, reducing inhibitions against aggression, compromising decision making processes, diminishing social networks, increasing physiological arousal and hindering the resolution of difficult situations. Finally, it reviews three skills thought to underlie deliberate emotion regulation: emotional awareness, emotional acceptance and proficiency in a variety of emotion regulation strategies. Treatment encompassing all of these skills may improve an individual's ability to regulate difficult emotion states more adaptively and thereby lessen aggressive behavior.     

Belief attribution in deaf and hearing infants

Based on anticipatory looking and reactions to violations of expected events, infants have been credited with 'theory of mind' (ToM) knowledge that a person's search behaviour for an object will be guided by true or false beliefs about the object's location. However, little is known about the preconditions for looking patterns consistent with belief attribution in infants. In this study, we compared the performance of 17- to 26-month-olds on anticipatory looking in ToM tasks. The infants were either hearing or were deaf from hearing families and thus delayed in communicative experience gained from access to language and conversational input. Hearing infants significantly outperformed their deaf counterparts in anticipating the search actions of a cartoon character that held a false belief about a target-object location. By contrast, the performance of the two groups in a true belief condition did not differ significantly. These findings suggest for the first time that access to language and conversational input contributes to early ToM reasoning.     

Collaborative partner or social tool? New evidence for young children’s understanding of joint intentions in collaborative activities

Some children’s social activities are structured by joint goals. In previous research, the criterion used to determine this was relatively weak: if the partner stopped interacting, did the child attempt to re‐engage her? But re‐engagement attempts could easily result from the child simply realizing that she needs the partner to reach her own goal in the activity (social tool explanation). In two experiments, 21‐ and 27‐month‐old children interacted with an adult in games in which they either did or did not physically need the partner to reach a concrete goal. Moreover, when the partner stopped interacting, she did so because she was either unwilling to continue (breaking off from the joint goal) or unable to continue (presumably still maintaining the joint goal). Children of both age groups encouraged the recalcitrant partner equally often whether she was or was not physically needed for goal attainment. In addition, they did so more often when the partner was unable to continue than when she was unwilling to continue. These findings suggest that young children do not just view their collaborative partners as mindless social tools, but rather as intentional, cooperative agents with whom they must coordinate intentional states.     

Origins of the human pointing gesture: a training study

Despite its importance in the development of children’s skills of social cognition and communication, very little is known about the ontogenetic origins of the pointing gesture. We report a training study in which mothers gave children one month of extra daily experience with pointing as compared with a control group who had extra experience with musical activities. One hundred and two infants of 9, 10, or 11 months of age were seen at the beginning, middle, and end of this one‐month period and tested for declarative pointing and gaze following. Infants’ability to point with the index finger at the end of the study was not affected by the training but was instead predicted by infants’ prior ability to follow the gaze direction of an adult. The frequency with which infants pointed indexically was also affected by infant gaze following ability and, in addition, by maternal pointing frequency in free play, but not by training. In contrast, infants’ ability to monitor their partner’s gaze when pointing, and the frequency with which they did so, was affected by both training and maternal pointing frequency in free play. These results suggest that prior social cognitive advances, rather than adult socialization of pointing per se, determine the developmental onset of indexical pointing, but socialization processes such as imitation and adult shaping subsequently affect both infants’ ability to monitor their interlocutor’s gaze while they point and how frequently infants choose to point.     

Understanding all inconsistency compensation as a palliative response to violated expectations

It has been repeatedly shown that, when people have experiences that are inconsistent with their expectations, they engage in a variety of compensatory efforts. Although there have been many superficially different accounts for these behaviors, a potentially unifying inconsistency compensation perspective is currently coalescing. Following from a common prediction error/conflict monitoring mechanism, any given inconsistency is understood as evoking a common syndrome of aversive arousal. In turn, this aversive arousal is understood to motivate palliative efforts, which manifest as the analogous compensation behaviors reported within different psychological literatures. Based on this perspective, compensation efforts following both 'high-level' (e.g., attitudinal dissonance) and 'low-level' (e.g., Stroop task color/word mismatches) inconsistencies can now be understood in terms of a common motivational account.     

Neural correlates of establishing, maintaining, and switching brain states

Although the study of brain states is an old one in neuroscience, there has been growing interest in brain state specification owing to MRI studies tracing brain connectivity at rest. In this review, we summarize recent research on three relatively well-described brain states: the resting, alert, and meditation states. We explore the neural correlates of maintaining a state or switching between states, and argue that the anterior cingulate cortex and striatum play a critical role in state maintenance, whereas the insula has a major role in switching between states. Brain state may serve as a predictor of performance in a variety of perceptual, memory, and problem solving tasks. Thus, understanding brain states is critical for understanding human performance.     

Text messaging amongst New Zealand drivers: Prevalence and risk perception

Recent work suggests that text messaging impairs simulated and actual driving performance and that this impairment exceeds that of conversing on a cell phone while driving. Additionally, research has shown that text messaging is common in several countries, and despite drivers acknowledging the high risk involved in doing so, drivers continue to engage in this behaviour – regardless of legislation banning it. A nationwide online survey in New Zealand, of 1057 respondents, collected anonymous self-report data regarding the frequency of cell phone use (conversing and text messaging) while driving, beliefs concerning the safety of conversing or text messaging while driving. This article presents part of the results of that study – focusing on text messaging behaviour and risk perception regarding text messaging while driving. Over half of respondents surveyed reported sending or reading between 1 and 5 text messages while driving in a typical week. Despite this, 89% of participants agreed that text messaging while driving in general impairs driving performance. There were no gender differences between the number of text messages read and sent. Age was found to be an important indicator of participant’s willingness to engage in text messaging while driving, with younger drivers more likely to engage in this behaviour. The implications of these findings for future research and countermeasure development are discussed.