A simplicity principle in unsupervised human categorization

We address the problem of predicting how people will spontaneously divide into groups a set of novel items. This is a process akin to perceptual organization. We therefore employ the simplicity principle from perceptual organization to propose a simplicity model of unconstrained spontaneous grouping. The simplicity model predicts that people would prefer the categories for a set of novel items that provide the simplest encoding of these items. Classification predictions are derived from the model without information either about the number of categories sought or information about the distributional properties of the objects to be classified. These features of the simplicity model distinguish it from other models in unsupervised categorization (where, for example, the number of categories sought is determined via a free parameter), and we discuss how these computational differences are related to differences in modeling objectives. The predictions of the simplicity model are validated in four experiments. We also discuss the significance of simplicity in cognitive modeling more generally.     

Perceptual adjustment to time-compressed speech: A cross-linguistic study

Previous research has shown that, when hearers listen to artificially speeded speech, their performance improves over the course of 10–15 sentences, as if their perceptual system was “adapting” to these fast rates of speech. In this paper, we further investigate the mechanisms that are responsible for such effects. In Experiment 1, we report that, for bilingual speakers of Catalan and Spanish, exposure to compressed sentences in either language improves performance on sentences in the other language. Experiment 2 reports that Catalan/Spanish transfer of performance occurs even in monolingual speakers of Spanish who do not understand Catalan. In Experiment 3, we study another pair of languages— namely, English and French—and report no transfer of adaptation between these two languages for English—French bilinguals. Experiment 4, with monolingual English speakers, assesses transfer of adaptation from French, Dutch, and English toward English. Here we find that there is no adaptation from French and intermediate adaptation from Dutch. We discuss the locus of the adaptation to compressed speech and relate our findings to other cross-linguistic studies in speech perception.     

Corruption as a Propensity: Personality and Motivational Determinants Among Nigerians

Psychologically oriented studies on corruption are lacking despite the fact that psychology has contributed enormously to the understanding of criminal behaviors over the past decades. Part of this problem relates to the lack of psychological tone in the definition and measurement of corruption. Taking a clue from the extensive psychological discourse on crime, which provides strong evidence for the existence of criminal tendencies, we conceptualized corruption here in terms of propensity. Possible personality and motivation determinants of this propensity were then explored. Results revealed that extraversion and conscientiousness positively and inversely predicted corruption tendencies, respectively. Results further showed that extrinsic motivation positively potentiates corruption tendencies, whereas intrinsic motivation was inversely related to corruption tendencies. Analysis of demographic variables revealed that males were more likely to be corrupt than their female counterparts. In general, findings here are consistent with the criminal behavior literature, which strongly suggests that the study of corruption is indeed amenable to psychological theories and methods and that individual differences variables constitute important explanatory variables in this regard.     

The notion of contextual locking: Previously learnt items are not accessible as such when appearing in a less common context

We examined the effect of context on the learning of spatial coding in four experiments. Two partially overlapping sets of stimuli, which had the very same stimulus–response spatial coding, were presented in unique contexts. Results show contextual locking—that is, response times to the very same item in a more common context (80%) were significantly shorter than those in a less common context (20%). Contextual locking was obtained both when the context was more salient (Experiments 1 and 2) and less salient (Experiments 3 and 4). In addition, results were obtained even when contextualization seemed less necessary (Experiments 2 and 4). Binding of information to context is discussed in relation to chunking, transfer effects, and practical applications pertaining to professional training.     

Application of GIS and multicriteria evaluation in locating sustainable boundary between the tunari National Park and Cochabamba City (Bolivia)

Increased population growth and urbanization, has caused increase in demand for land around the city of Cochabamba, which has led to encroachment into the National Park and the construction of illegal settlements. This has created a number of problems, some of which are the direct consequences of the new settlements in the ‘Tunari’ foothills. These settlements constitute a threat to the environment and people because of their location in flood risk and aquifer recharge areas. In response to this problem the city authorities are considering relocating the boundary between the National Park and the city. This study has focused on the design and evaluation of alternative locations for a sustainable boundary between the north of ‘Cochabamba City’ and the southern boundary of the ‘Tunari National Park’. In this process, a rational and systematic approach of collaborative‐decision‐making, supported by geographical information systems (GIS) and multicriteria evaluation (MCE) has been employed and evaluated. Copyright © 2003 John Wiley & Sons, Ltd.     

Psychosocial impacts of communal conflicts in a sample of secondary school youths from two conflict communities in south east Nigeria

In Nigeria, communal conflicts arise due to misunderstanding from ownership of land for farming, oil deposits, solid minerals or water for fishing activities. It may also arise in defence of community pride and properties or even in defence of the people involved in the conflict. The General Health Questionnaire (GHQ-12), The Short Screening Scale for Post traumatic stress disorder, The Generalized Anxiety Disorder Scale (GAD-7) and the Beck Depression Inventory (BDI-2) were used to assess psychosocial impacts of communal conflicts among 560 secondary school youths from two communities in south east Nigeria. Result revealed various forms of psychosocial impacts of communal conflicts among the youths.     

Relationships between work-related characteristics,needs satisfaction,motivation and mental health in midwifery students

The present study examined the relationships between work-related characteristics in internships, psychological needs satisfaction, motivation and mental health using a partial least squares path modeling. Midwifery students (N = 214; M_age = 22.8 years) from three French schools completed different questionnaires online. Results showed (1) the importance of work resources (work control and social support) as protective factors of psychological needs satisfaction; and (2) the role of competence need satisfaction through motivation in the relationships between work resources and mental health. Midwifery schools should pay more attention to these two results, and take them into account in midwifery students’ training.     

Automatic auditory disambiguation of visual awareness

Multisensory integration can play a critical role in producing unified and reliable perceptual experience. When sensory information in one modality is degraded or ambiguous, information from other senses can crossmodally resolve perceptual ambiguities. Prior research suggests that auditory information can disambiguate the contents of visual awareness by facilitating perception of intermodally consistent stimuli. However, it is unclear whether these effects are truly due to crossmodal facilitation or are mediated by voluntary selective attention to audiovisually congruent stimuli. Here, we demonstrate that sounds can bias competition in binocular rivalry toward audiovisually congruent percepts, even when participants have no recognition of the congruency. When speech sounds were presented in synchrony with speech-like deformations of rivalling ellipses, ellipses with crossmodally congruent deformations were perceptually dominant over those with incongruent deformations. This effect was observed in participants who could not identify the crossmodal congruency in an open-ended interview (Experiment 1) or detect it in a simple 2AFC task (Experiment 2), suggesting that the effect was not due to voluntary selective attention or response bias. These results suggest that sound can automatically disambiguate the contents of visual awareness by facilitating perception of audiovisually congruent stimuli.     

RSK2 signaling in brain habenula contributes to place aversion learning

RSK2 is a Ser/Thr kinase acting in the Ras/MAPK pathway. Rsk2 gene deficiency leads to the Coffin-Lowry Syndrome, notably characterized by cognitive deficits. We found that mrsk2 knockout mice are unable to associate an aversive stimulus with context in a lithium-induced conditioned place aversion task requiring both high-order cognition and emotional processing. Virally mediated shRNA-RSK2 knockdown in the habenula, whose involvement in cognition is receiving increasing attention, also ablated contextual conditioning. RSK2 signaling in the habenula, therefore, is essential for this task. Our study reveals a novel role for RSK2 in cognitive processes and uncovers the critical implication of an intriguing brain structure in place aversion learning.