Knowledge,Truth and Plausibility

From antiquity several philosophers have claimed that the goal of natural science is truth. In particular, this is a basic tenet of contemporary scientific realism. However, all concepts of truth that have been put forward are inadequate to modern science because they do not provide a criterion of truth. This means that we will generally be unable to recognize a scientific truth when we reach it. As an alternative, this paper argues that the goal of natural science is plausibility and considers some characters of plausibility.     

Editors’ introduction: social dynamics and collective rationality

We provide a brief introduction to this special issue on social dynamics and collective rationality, and summarize the gist of the papers collected therein.     

Distinguishing Personality Psychopathology Five (PSY–5) Characteristics Associated With Violent and Nonviolent Juvenile Delinquency

This study examined the relationship between the Minnesota Multiphasic Personality Inventory–Adolescent (MMPI–A) Personality Psychopathology Five (PSY–5) scales and violent and nonviolent juvenile delinquency. Participants were 260 adolescent boys and girls in a forensic setting. Results indicated that Disconstraint (DISC), a marker of behavioral disinhibition and impulsivity, was associated with nonviolent delinquency, whereas Aggressiveness (AGGR), which is characterized by the use of instrumental aggression and interpersonal dominance, was specifically associated with violent delinquency. These findings are consistent with expectations based on empirical findings in the broader personality literature linking the construct of disinhibition with externalizing psychopathology as well as the literature identifying callous-unemotional aggression as a risk factor for violence.     

A DDL Approach to Pluralistic Ignorance and Collective Belief

A group is in a state of pluralistic ignorance (PI) if, roughly speaking, every member of the group thinks that his or her belief or desire is different from the beliefs or desires of the other members of the group. PI has been invoked to explain many otherwise puzzling phenomena in social psychology. The main purpose of this article is to shed light on the nature of PI states – their structure, internal consistency and opacity – using the formal apparatus of Dynamic Doxastic Logic, and also to study the sense in which such states are “fragile”, i.e. to identify plausible conditions under which a PI state cascades into a state of shared belief as the result of announcement.     

Smiling in newborns during communicative wake and active sleep

Many studies have investigated infant smiling behaviour during wake and active sleep. In the majority of studies authors agreed that two month-old infants exhibit social smiles. However it is not clear if newborns exhibit different kinds of smiles during wake and active sleep to two month-old infants and if the communicative context can affect the quantity and quality of these smiles.The aim of this study was to test if different kinds of communication affects the amount and the quality of smiles during different behavioural states.Smiling behaviour was analyzed during interactive wake (IW) and active sleep (AS), in 40 newborns randomly assigned to 4 groups of 10 newborns each: continuous tactile communication group, discontinuous non periodic tactile communication group, discontinuous periodic tactile communication group, absent communication group. In the total sample the open/closed mouth (social/non social) smiles ratio was 38/5 during IW and 1/28 during AS (p < .001). Moreover these ratios were different between the four groups.Different kinds of tactile communication affect amount and quality of the smiles of newborns during IW and AS. Moreover the morphological difference of the smiles during IW and AS suggested that for newborns the smiling behaviour during IW could have a social meaning, as it does for two month-old infants.     

Dynamics of the ankle joint analyzed through moment-angle loops during human walking: gender and age effects

Aim of this study was to provide a non-invasive assessment of the dynamic properties of the ankle joint during human locomotion, with specific focus on the effects of gender and age. Accordingly, flexion-extension angles and moments, obtained through gait analysis, were used to generate moment–angle loops at the ankle joint in 120 healthy subjects walking at a same normalized speed. Four reproducible types of loops were identified: Typical Loops, Narrow, Large and Yielding loops. No significant changes in the slopes of the main loop phases were observed as a function of gender and age, with the exception of a relative increase in the slope of the descending phase in elderly males compared to adult females. As for the ergometric parameters, the peak ankle moment, work produced and net work along the cycle were slightly, but significantly affected, with progressively decrease in the following order: Adult Males, Adult Females, Elderly Males and Elderly Females. The evidence that only few of the quantitative aspects of moment–angle loops were affected suggests that the control strategy which regulates the biomechanical properties of the ankle joint during walking is rather robust and qualitatively consistent across genders and age.     

Interactions between perceptual and numerical space

Interactions between numbers and space have become a major issue in numerical cognition. Neuropsychological studies suggest that the interactions occur, before response selection, at a spatially organized representation of numbers (the mental number line). Reaction time (RT) studies, on the other hand, usually point to associations between response codes that do not necessarily imply a number line. There is only one such study that has found a spationumerical interaction between perception and semantics (SNIPS) effect before response selection. Here, in Experiment 1, we isolated the SNIPS effect from other numerical effects and corroborated the prediction that it can be induced by both left and right spatial cues. In Experiment 2, we isolated the peak of the time course of the SNIPS effect and corroborated the prediction that it occurs when a cue follows a target, and not when both appear simultaneously. The results reconcile neuropsychological and RT studies and support the hypothesis that numbers are represented along a left-to-right spatially organized mental number line. [corrected]     

A Simon effect for depth in three-dimensional displays

We investigated whether the Simon effect occurs for the depth dimension in a 3-dimensional display. In Experiment 1, participants executed discriminative responses to 2 stimuli, a cross and a sphere, both 3-dimensional, which were perceived to be located near or far with respect to the participant's body. The response keys were located near and far along the participant's midline. Apparent stimulus spatial location (near or far) was irrelevant to the task. Results showed a depth Simon effect, attributable to the apparent stimulus spatial location. Experiment 2 replicated Experiment 1 with a different procedure. The 2 stimuli, a triangle and a rectangle, were 2-dimensional and were perceived as being located near or far from the participant's midline; the response keys were located near and far along the participant's midline. Results showed again the depth Simon effect. Experiment 3 was a control condition in which the 2 stimuli, drawings of a lamp and of a chair, had the same size, regardless of whether they appeared to be near or far. The depth Simon effect was replicated. A distribution analysis on data of Experiment 3 showed that the Simon effect increased as reaction times became longer. In Experiment 4, the position of the 2 stimuli, a circle and a cross, varied on the horizontal (right or left) dimension, whereas the position of the 2 responses varied along the depth (near or far) dimension. No Simon effect was found.     

The relation between ethnic group attachment and prosocial tendencies: The mediating role of cultural values

Studies suggest that Mexican–American youths who feel attached to their ethnic group engage in more prosocial behaviors. However, the psychological mechanisms that account for this association are not clear. Drawing on social identity and self‐categorization theories, we examined whether the association between ethnic group attachment and tendencies to engage in six distinct types of prosocial behaviors was mediated by familism and Mainstream American values among Mexican American youths. Ethnic group attachment, familism, Mainstream American values, and prosocial tendencies were assessed among 207 Mexican–American early adolescents using an interview format. Latent variable path models showed that ethnic group attachment was associated with greater tendencies to engage in compliant, emotional, dire, and anonymous helping, and that each of these associations was at least partially mediated by greater familism values. Mainstream American values were related to greater tendencies to engage in public prosocial behavior and less altruistic behavior, but did not mediate the associations between ethnic group attachment and prosocial tendencies. The theoretical and practical implications of these findings are addressed. Copyright © 2010 John Wiley & Sons, Ltd.