Cognitive and neural modeling of dynamics of trust in competitive trustees

Trust dynamics can be modeled in relation to experiences. In this paper two models to represent human trust dynamics are introduced, namely a model on a cognitive level and a neural model. These models include a number of parameters, providing the possibility to express certain relations between trustees. The behavior of each of the models is further analyzed by means of simulation experiments and formal verification techniques. Thereafter, both models have been compared to see whether they can produce patterns that are comparable. As each of the models has its own specific set of parameters, with values that depend on the type of person modeled, such a comparison is non-trivial. To address this, a special comparison approach is introduced, based on mutual mirroring of the models in each other. More specifically, for a given parameter values set for one model, by an automated parameter estimation procedure the most optimal values for the parameter values of the other model are determined in order to show the same behavior. Roughly spoken the results are that the models can mirror each other up to an accuracy of around 90%.     

Agonistic rank,aggression, social context,and testosterone in male pigtail monkeys

Two groups of pigtail monkeys were merged, a third was formed, and individual males were introduced into a group in a series of experiments examining the effects of social context upon agonistic rank, aggressive expression, and testosterone levels. In the first experiment, two heterosexual groups, containing adult males unfamiliar to the other group, were merged. The two groups fought, and the smaller group was defeated. The alpha and beta males of the defeated group were singled out for repeated attack and both showed significant drops in circulating levels of testosterone. Both males were removed from the group during the first day, but testosterone levels did not recover to baseline levels for several days. The alpha male of the victorious group, on the other hand, showed a significant rise in testosterone, which was apparent only on the day following the merger. In order to study the influence of previous social familiarity on male reception into a group, another group was formed by removing males from the victorious group and placing them in a separate enclosure. The males in the new group established a dominance hierarchy unrelated to their previous social ranks with one another. Three months later, each of the six adult males remaining in the parent group was individually introduced into the new group for one day or less. Each of the males introduced into the new group accepted a social position at the lower end of the dominance hierarchy without regard to his previous rank relationships with the host males when they were all in the parent group. Even the alpha and beta males of the parent group were relegated to low rank positions in the new group, despite having ranked over each of the host males since birth. In contrast to the aggression directed at the unfamiliar males in the first experiment, a minimum of aggression was directed to the familiar males introduced into the new group in the second experiment. Although the males introduced accepted low social ranks, it appeared that each was readily integrated into the group with a minimum of aggressive interaction during the time he was scheduled to remain in the group. There were no significant changes in circulating levels of testosterone in any of the males during the introductions of familiar males to one another.     

More than words: Judgments of politicians and the role of different communication channels

We collected short video clips of speakers and created five types of stimuli: (1) the original videos, (2) the audio tracks only, (3) single pictures only, (4) speech content, and (5) stick-figure animations displaying body motion. Participants rated these stimuli on a brief Big Five personality inventory. We then used ratings of the incomplete information conditions to predict ratings of the original video condition. Impressions in the audio track condition were strong predictors throughout all trait ratings. However, other cues were also non-negligible contributors to an overall impression. People even make sense of parsimonious cues, e.g., an animated stick-figure. Thus, presenters on a public stage are not only judged by what they say but also by how they move.     

Children's and adults' understanding of the impact of nutrition on biological and psychological processes

Four studies examined children's and adults' beliefs about the impact of nutrition on growth and mood states. In Studies 1 and 2, 271 participants (preschoolers through adults) judged the impact of healthy and unhealthy nutrition on height and weight. In Studies 3 and 4, 267 participants judged the impact of healthy and unhealthy nutrition on positive and negative mood states. The results suggest that young children demonstrate a co‐existence of an ontologically distinct theory of biology as well as a theory of cross‐domain interaction when reasoning about the impact of food on biological and psychological processes.     

The affiliative consequences of same-race and cross-race mimicry

ABSTRACT

Few studies have replicated and extended the classic mimicry → liking effect. The present research sought to (a) replicate the affiliative consequences of mimicry; (b) test whether the affiliative consequences hold in a context where mimicry may not be normative (i.e., cross-race interactions); and (c) investigate how excluded individuals respond to same- versus cross-race mimicry and non-mimicry. Participants wrote about a control topic or social exclusion and then engaged in a brief laboratory interaction in which they were mimicked or not mimicked by a confederate who was either same-race or cross-race. Then they reported how much they liked the confederate. Within the control condition, the effect of mimicry on affiliation depended on the race of the confederate – but this pattern did not emerge for excluded individuals. The study was unable to conclusively replicate and extend previous findings. The authors make recommendations to promote a more cumulative science of behavioral mimicry.     

Whose promises are worth more? How social status affects trust in promises

Promises are among the most widely used tools for increasing trust in social hierarchies; yet the effect of social status on trust in promises is unknown. Here we used a modified version of the Trust Game, in which participants, acting as Investors, were paired with Trustees of varying social status who were given the opportunity to promise (or not) to return at least half of the multiplied amount (i.e., 4 × the amount invested). No return feedback was provided. Participants invested more in partners who promised than those who did not or whose promise information was concealed. Importantly, in both lab-manipulated (Exps. 1–3: math-induced) and pre-existing (Exp. 4: university-based) hierarchies, participants invested more in promises given by high status than low status partners. Post-experiment measures suggest that this may be due to greater expectations of honesty for high status than low status others. Potential explanations and implications are discussed.