P matrix properties, injectivity, and stability in chemical reaction systems

In this paper we examine matrices which arise naturally as Jacobians in chemical dynamics. We are particularly interested in when these Jacobians are P matrices (up to a sign change), ensuring certain bounds on their eigenvalues, precluding certain behaviour such as multiple equilibria, and sometimes implying stability. We first explore reaction systems and derive results which provide a deep connection between system structure and the P matrix property. We then examine a class of systems consisting of reactions coupled to an external rate-dependent negative feedback process, and characterise conditions which ensure the P matrix property survives the negative feedback. The techniques presented are applied to examples published in the mathematical and biological literature

Social categories guide young children’s preferences for novel objects

To whom do children look when deciding on their own preferences? To address this question, 3-year-old children were asked to choose between objects or activities that were endorsed by unfamiliar people who differed in gender, race (White, Black), or age (child, adult). In Experiment 1, children demonstrated robust preferences for objects and activities endorsed by children of their own gender, but less consistent preferences for objects and activities endorsed by children of their own race. In Experiment 2, children selected objects and activities favored by people of their own gender and age. In neither study did most children acknowledge the influence of these social categories. These findings suggest that gender and age categories are encoded spontaneously and influence children's preferences and choices. For young children, gender and age may be more powerful guides to preferences than race.Psycholog

Patterns of Implicit and Explicit Attitudes in Children and Adults: Tests in the Domain of Religion

Among the most replicated results in social cognition is the split between explicit and implicit attitudes; adults demonstrate weaker group-based preferences on explicit rather than implicit measures. However, the developmental origins of this pattern remain unclear. If implicit attitudes develop over a protracted period of time, children should not demonstrate the implicit preferences observed among adults. Additionally, unlike adults, children may report group-based preferences due to their lesser concern with social desirability. In Study 1, Christian adults showed the expected pattern of robust implicit preference but no explicit preference. In 4 additional experiments, 6- to 8-year-old children whose parents identified them as Christian viewed characters described as belonging to 2 starkly different religious groups (“strong religious difference”) or 2 relatively similar religious groups (“weak religious difference”). Participants then completed explicit and implicit (IAT) measures of attitude toward Christians and either Hindus (Study 2) or Jews (Studies 3–5). Three main results emerged. First, like adults, children showed significant implicit pro-Christian preferences across all studies. Second, unlike adults, children in the “strong religious difference” case reported preferences of approximately the same magnitude as their implicit attitudes (i.e., no dissociation). Third, even in the “weak religious difference” case, children showed implicit pro-Christian preferences (although, like adults, their explicit attitudes were not sensitive to intergroup difference). These data suggest that the seeds of implicit religious preferences are sown early and that children’s explicit preferences are influenced by the social distance between groups.Psycholog

What do different beliefs tell us? An examination of factual, opinion-based, and religious beliefs

Children and adults differentiate statements of religious belief from statements of fact and opinion, but the basis of that differentiation remains unclear. Across three experiments, adults and 8–10-year-old children heard statements of factual, opinion-based, and religious belief. Adults and children judged that statements of factual belief revealed more about the world, statements of opinion revealed more about individuals, and statements of religious belief provided information about both. Children—unlike adults—judged that statements of religious belief revealed more about the world than the believer. These results led to three conclusions. First, judgments concerning the relative amount of information statements of religious belief provide about individuals change across development, perhaps because adults have more experience with diversity. Second, recognizing that statements of religious belief provide information about both the world and the believer does not require protracted learning. Third, statements of religious belief are interpreted as amalgams of factual and opinion-based statements.Psycholog

Children's Responses to Group-Based Inequalities: Perpetuation and Rectification

The current studies investigate whether, and under what conditions, children engage in system-perpetuating and system-attenuating behaviors when allocating resources to different social groups. In three studies, we presented young children with evidence of social group inequalities and assessed whether they chose to perpetuate or rectify these inequalities. Children (aged 3.5–11.5 years) heard about two social groups (i.e., racial or novel groups) whose members received resources unequally (two cookies versus one). Participants were then given the opportunity to distribute additional resources to new members of the same groups. In Experiment 1, when children were presented with inequalities involving groups of Blacks and Whites, older children (aged 7.5–11.5 years) rejected the status quo, providing more resources to members of groups with fewer resources (White or Black), whereas younger children (aged 3.5–7.5 years) perpetuated the status quo. In Experiments 2 and 3, the inequalities involved Asians and Whites and novel groups. Children of all ages perpetuated inequality, with rectification strategies applied only by older children and only when Black targets were involved in the inequality. Equal sharing occasionally occurred in older children but was never a common response. These findings provide evidence that system-perpetuating tendencies may be predominant in children and suggest that socialization may be necessary to counter them.Psycholog

Female Faculty: Why So Few and Why Care?

Despite slow ongoing progress in increasing the representation of women in academia, women remain significantly under-represented at senior levels, in particular in the natural sciences and engineering. Not infrequently, this is downplayed by bringing forth arguments such as inherent biological differences between genders, that current policies are adequate to address the issue, or by deflecting this as being “not my problem” among other examples. In this piece we present scientific evidence that counters these claims, as well as a best-practice example, Genie, from Chalmers University of Technology, where one of the authors is currently employed. We also highlight particular challenges caused by the current COVID-19 pandemic. Finally, we conclude by proposing some possible solutions to the situation and emphasize that we need to all do our part, to ensure that the next generation of academics experience a more diverse, inclusive, and equitable working environment

Judgements of the Lucky Across Development and Culture

For millennia human beings have believed that it is morally wrong to judge others by the fortuitous or unfortunate events that befall them or by the actions of another person. Rather, an individual’s own intended, deliberate actions should be the basis of his/her evaluation, reward and punishment. In a series of studies we investigate whether such rules guide the judgments of children. The first three studies demonstrate that children view lucky others as more likely than unlucky others to perform intentional good actions. Children similarly assess the siblings of lucky others as more likely to perform intentional good actions than the siblings of unlucky others. The next three studies demonstrate that children as young as 3 years believe that lucky people are nicer than unlucky people. The final two studies find that Japanese children also demonstrate a robust preference for the lucky and their associates. These findings are discussed in relation to Lerner’s just world theory and Piaget’s immanent justice research and in relation to the development of intergroup attitudes.Psycholog

The Development of Reasoning About Beliefs: Fact, Preference, and Ideology

The beliefs people hold about the social and physical world are central to self-definition and social interaction. The current research analyzes reasoning about three kinds of beliefs: those that concern matters of fact (e.g., dinosaurs are extinct), preference (e.g., green is the prettiest color), and ideology (e.g., there is only one God). The domain of ideology is of unique interest because it is hypothesized to contain elements of both facts and preferences. If adults' distinct reasoning about ideological beliefs is the result of prolonged experience with the physical and social world, children and adults should reveal distinct patterns of differentiating kinds of beliefs, and this difference should be particularly pronounced with respect to ideological beliefs. On the other hand, if adults' reasoning about beliefs is a basic component of social cognition, children and adults should demonstrate similar belief representations and patterns of belief differentiation. Two experiments demonstrate that 5–10 year old children and adults similarly judged religious beliefs to be intermediate between factual beliefs (where two disagreeing people cannot both be right) and preferences (where they can). From the age of 5 years and continuing into adulthood, individuals distinguished ideological beliefs from other types of mental states and demonstrated limited tolerance for belief-based disagreements.Psycholog

The Role of Forgetting in Undermining Good Intentions

Evaluating others is a fundamental feature of human social interaction–we like those who help more than those who hinder. In the present research, we examined social evaluation of those who not only intentionally performed good and bad actions but also those to whom good things have happened (the lucky) and those to whom bad things have happened (the unlucky). In Experiment 1a, subjects demonstrated a sympathetic preference for the unlucky. However, under cognitive load (Experiment 1b), no such preference was expressed. Further, in Experiments 2a and 2b, when a time delay between impression formation (learning) and evaluation (memory test) was introduced, results showed that younger (Experiment 2a) and older adults (Experiment 2b) showed a significant preference for the lucky. Together these experiments show that a consciously motivated sympathetic preference for those who are unlucky dissolves when memory is disrupted. The observed dissociation provides evidence for the presence of conscious good intentions (favoring the unlucky) and the cognitive compromising of such intentions when memory fails