A simulated annealing methodology for clusterwise linear regression

In many regression applications, users are often faced with difficulties due to nonlinear relationships, heterogeneous subjects, or time series which are best represented by splines. In such applications, two or more regression functions are often necessary to best summarize the underlying structure of the data. Unfortunately, in most cases, it is not known a priori which subset of observations should be approximated with which specific regression function. This paper presents a methodology which simultaneously clusters observations into a preset number of groups and estimates the corresponding regression functions' coefficients, all to optimize a common objective function. We describe the problem and discuss related procedures. A new simulated annealing-based methodology is described as well as program options to accommodate overlapping or nonoverlapping clustering, replications per subject, univariate or multivariate dependent variables, and constraints imposed on cluster membership. Extensive Monte Carlo analyses are reported which investigate the overall performance of the methodology. A consumer psychology application is provided concerning a conjoint analysis investigation of consumer satisfaction determinants. Finally, other applications and extensions of the methodology are discussed.     

Conceptualizing Attachment Trauma: Exploring Emotional Vulnerabilities among Disaster Affected Children of Gujarat

This study compares attachment trauma and psychological adjustment of child survivors of an earthquake and social violence in Gujarat (n = 127). In particular it explores attachment style/s associated with the two disaster traumas and tries to explicate, what these tell us about the particular vagaries of trauma. Results show larger number of insecurely attached children in the disaster trauma sample and the dismissing attachment style dominates particularly in the earthquake sample whereas in the riots sample one can see a presence of what can be termed as a ‘mixed attachment’ style-vacillation between dismissing and preoccupied states of mind. The implications of these findings for a conceptualization of attachment trauma are discussed in details.     

A new American dilemma? The effect of ethnic identification and public service on the national inclusion of ethnic minorities

Three experiments integrate research from political science and social psychology to examine the consequences of two competing visions of American national identity. American identity has been defined not only in terms of shared ethnocultural heritage originating in Europe (the ethnocultural prototype) but also in terms of shared commitment to civic service (the civic responsibility prototype). Three experiments tested the consequence of highlighting each of these national prototypes on perceivers' inclusion of ethnic minorities as legitimately American. Experiments 1–3 showed that highlighting ethnic minorities' allegiance to their ethnic subgroup (versus downplaying it) challenges the ethnocultural prototype and makes ethnic minorities appear less American. Process data showed that this effect was mediated by increased threats to American distinctiveness. By contrast, emphasizing ethnic minorities' national service (versus local community service) highlights ethnic minorities' fit with the civic responsibility prototype and makes ethnic minorities appear more American (Experiments 2–3). Process data showed that this effect was mediated by enhanced American distinctiveness. Collectively, these experiments highlight how inclusion of ethnic minorities in the nation can wax and wane depending on which definition of national character is salient in the social context. Copyright © 2012 John Wiley & Sons, Ltd.     

On the time course of exogenous cueing effects in bilinguals: higher proficiency in a second language is associated with more rapid endogenous disengagement

Previous investigations have demonstrated a bilingual advantage on various aspects of executive control. It remains unclear how the language proficiency of bilinguals might relate to the mechanisms involved in attentional disengagement. In the present investigation, we tested the hypothesis that high bilingual proficiency would lead to a more rapid endogenous disengagement of attention from task-irrelevant peripheral cues. We predicted that more rapid attentional disengagement would result in an earlier appearance of inhibition of return (IOR). In this study Hindi-English bilinguals who differed in their L2 (English) proficiency participated in a target detection task. Visual targets were preceded by uninformative peripheral cues at various stimulus onset asynchronies (SOAs) allowing for us to visualize the time course of cue-related facilitation and inhibition. High-proficient Hindi-English bilinguals showed an earlier appearance of IOR than did low-proficient bilinguals, suggesting increased efficiency in disengagement of attention from task-irrelevant inputs. Furthermore, consistent with the "global" advantage that characterizes bilinguals in many tasks, the high-proficient group outperformed low-proficient bilinguals in overall reaction time.     

Piagetian Studies of Cognitive Development in India

The paper presents a review of studies on cognitive development of children in India inspired by Piaget’s theory of cognitive development. Piaget’s theory is briefly introduced before examining its cross-cultural applications. Early studies of cognitive development, which focus on age-related changes in cognition, are described. These are followed by the studies of the last decades in which developmental contexts, such as those provided by ecology, culture, schooling, and various forms of training, are implicated. Studies of spatial cognition are discussed in some detail and points of convergence between findings of Indian studies and those reported by Piaget are critically examined. The issue of “performance” vs. “competence” is addressed and research evidence that considers performance difference as a matter of cognitive style is presented. Possible reasons for decline of research interest in Piagetian studies in recent years is examined and suggestion for future studies in this field are offered.     

Downsizing and Supersizing: How Changes in Product Attributes Influence Consumer Preferences

This paper investigates how changing the value of one attribute while keeping other attributes constant influences consumers' judgments and behaviors. We find that in two options, a proportionally equal change in one attribute tilts people's preference toward the option with higher (or lower) absolute magnitude of change when the change is desirable (or undesirable). We propose that when individuals face an attribute change, they use a deliberative and effortful response, known as System 2, to detect the change. However, they rely less on this system to evaluate the changed options. Instead, a more automatic System 1 processing influences their decision by making them apply the bigger‐is‐better heuristic (bigger‐is‐worse for an undesirable change) to prefer the option with the highest (lowest) absolute magnitude of change. Six studies demonstrate this phenomenon in both lab and real settings and support our hypothesis. Copyright © 2013 John Wiley & Sons, Ltd.     

The Rāga Bhāva in the Sāṁkhya Kārikā: Rectifying an Age-Old Mistake

The last foot of the 23rd verse of the Sā?khya Kārikā (SK)—‘tāmasam asmāt viparyastam’—is in need of reinterpretation. Prevailing interpretations are generally based on the primary meaning of the verse. In that sense, it is understood as a declaration of the four tāmasika bhāva that are contrary to the sāttvika ones. Taking the primary meaning of the verse is problematic because it contradicts the gu?a-bhāva coherence required by the doctrine of satkārya. The doctrine of satkārya is one of the foundational principles of Sā?khya. The avirāga or rāga bhāva shows coherence to rajas rather than tamas. I show that the verse needs to be interpreted by taking the secondary meaning. Accordingly, avirāga or rāga is established as a bhāva of rajas rather than tamas. Further, I also show that the idea of bhāva in the Sā?khya Kārikā and the Bhagavadgītā may be closely related.     

Prior Related Work Experience and Job Performance: Role of personality

In contrast to the general notion, recent studies presented a negative or insignificant relationship between prior related work experience (PRWE) and job performance (JP) and suggestively attributed the theoretically inconsistent results to individual factors. Using a sample of 688 sales persons in the insurance industry, the present study found support for the positive relationship between PRWE and JP. Further, the study found the moderation effect of personality factors on the above relationship. Implication of the study to the practitioners and the academia is discussed.     

Perception of individuality in bat vocal communication: discrimination between, or recognition of, interaction partners?

Different cognitive processes underlying voice identity perception in humans may have precursors in mammals. A perception of vocal signatures may govern individualised interactions in bats, which comprise species living in complex social structures and are nocturnal, fast-moving mammals. This paper investigates to what extent bats recognise, and discriminate between, individual voices and discusses acoustic features relevant for accomplishing these tasks. In spontaneous presentation and habituation–dishabituation experiments, we investigated how Megaderma lyra perceives and evaluates stimuli consisting of contact call series with individual-specific signatures from either social partners or unknown individuals. Spontaneous presentations of contact call stimuli from social partners or unknown individuals elicited strong, but comparable reactions. In the habituation–dishabituation experiments, bats dishabituated significantly to any new stimulus. However, reactions were less pronounced to a novel stimulus from the bat used for habituation than to stimuli from other bats, irrespective of familiarity, which provides evidence for identity discrimination. A model separately assessing the dissimilarity of stimuli in syllable frequencies, syllable durations and inter-call intervals relative to learned memory templates accounted for the behaviour of the bats. With respect to identity recognition, the spontaneous presentation experiments were not conclusive. However, the habituation–dishabituation experiments suggested that the bats recognised voices of social partners as the reaction to a re-habituation stimulus differed after a dishabituation stimulus from a social partner and an unknown bat.