The apes’ edge: positional learning in chimpanzees and humans

A wide variety of organisms produce actions and signals in particular temporal sequences, including the motor actions recruited during tool-mediated foraging, the arrangement of notes in the songs of birds, whales and gibbons, and the patterning of words in human speech. To accurately reproduce such events, the elements that comprise such sequences must be memorized. Both memory and artificial language learning studies have revealed at least two mechanisms for memorizing sequences, one tracking co-occurrence statistics among items in sequences (i.e., transitional probabilities) and the other one tracking the positions of items in sequences, in particular those of items in sequence-edges. The latter mechanism seems to dominate the encoding of sequences after limited exposure, and to be recruited by a wide array of grammatical phenomena. To assess whether humans differ from other species in their reliance on one mechanism over the other after limited exposure, we presented chimpanzees (Pan troglodytes) and human adults with brief exposure to six items, auditory sequences. Each sequence consisted of three distinct sound types (X, A, B), arranged according to two simple temporal rules: the A item always preceded the B item, and the sequence-edges were always occupied by the X item. In line with previous results with human adults, both species primarily encoded positional information from the sequences; that is, they kept track of the items that occurred in the sequence-edges. In contrast, the sensitivity to co-occurrence statistics was much weaker. Our results suggest that a mechanism to spontaneously encode positional information from sequences is present in both chimpanzees and humans and may represent the default in the absence of training and with brief exposure. As many grammatical regularities exhibit properties of this mechanism, it may be recruited by language and constrain the form that certain grammatical regularities take.     

Free-ranging rhesus monkeys spontaneously individuate and enumerate small numbers of non-solid portions

Fundamental questions in cognitive science concern the origins and nature of the units that compose visual experience. Here, we investigate the capacity to individuate and store information about non-solid portions, asking in particular whether free-ranging rhesus monkeys (Macaca mulatta) quantify portions of a non-solid substance presented in discrete pouring actions. When presented with portions of carrot pieces poured from a cup into opaque boxes, rhesus picked the box with the greatest number of portions for comparisons of 1 vs. 2, 2 vs. 3, and 3 vs. 4, but not for comparisons of 4 vs. 5 and 3 vs. 6. Additional experiments indicate that rhesus based their decisions on both the number of portions and the total amount of food. These results show that the capacity to individuate non-solid portions is not unique to humans, and does not depend on structures of natural language. Further, the fact that rhesus' ability to represent non-solid portions is constrained by the same 4-item limit typically ascribed to the system of parallel individuation that operates over solid objects suggests that the visual system recruits common working memory processes for retaining information about solid objects and non-solid portions. We discuss our results with respect to theories of visual processing, as well as to the role that the human language faculty may have played in both the evolution and development of quantification.     

The Relationship between Creative Personality Composition,Innovative Team Climate,and Team Innovativeness: An Input — Process — Output Perspective

This study investigates the relationship between creative personality composition, innovative team climate, and team innovation based on an input‐process‐output model. We measured personality with the Creative Person Profile, team climate with the Team Climate Inventory, and team innovation through team‐member and supervisor reports of team innovativeness. The personality composition in each of 29 teams in a television production company was operationalized by mean scores for each creative personality variable, as well as the combination of different creative personality variables within a team. The team climate variable “vision” mediated the relationship between the mean level of associative orientation in teams and team innovation. The team climate variable “support of innovation” mediated the relationship between the joint variables of mean level of ambition x mean level of motivation and team innovation. The results indicated that when there are relationships between creative personality composition and team innovativeness, they are mediated by an innovative team climate.     

Ego Development and Psychosocial Functioning in Young Adults With and Without Psychiatric History

Ego development has been associated with positive outcomes, namely, with a better psychosocial adjustment and establishment of satisfactory relationships. However, ego development and psychosocial functioning are independent domains and a developed ego does not guarantee successful adaptation. Moreover, it is not clear whether ego development differentially influences psychosocial functioning in clinical and normative samples. The present study investigated the impact of ego development on the psychosocial functioning of young adults with (high-risk) and without (normative) psychiatric history. Results show an association between those two variables, especially strong for the high-risk group. High-risk individuals with successful psychosocial functioning exhibited levels of ego development more similar to those of normative young adults than to those of the remaining high-risk individuals. Moreover, as predicted, ego development mediated the relationship between psychiatric history and psychosocial functioning. Further support was found for the protective role of ego development, especially for individuals with psychiatric history.     

The role of speech rhythm in language discrimination: further tests with a non-human primate

Human newborns discriminate languages from different rhythmic classes, fail to discriminate languages from the same rhythmic class, and fail to discriminate languages when the utterances are played backwards. Recent evidence showing that cotton-top tamarins discriminate Dutch from Japanese, but not when utterances are played backwards, is compatible with the hypothesis that rhythm discrimination is based on a general perceptual mechanism inherited from a primate ancestor. The present study further explores the rhythm hypothesis for language discrimination by testing languages from the same and different rhythmic class. We find that tamarins discriminate Polish from Japanese (different rhythmic classes), fail to discriminate English and Dutch (same rhythmic class), and fail to discriminate backwards utterances from different and same rhythmic classes. These results provide further evidence that language discrimination in tamarins is facilitated by rhythmic differences between languages, and suggest that, in humans, this mechanism is unlikely to have evolved specifically for language.     

Computational and behavioral markers of model-based decision making in childhood

Human decision-making is underpinned by distinct systems that differ in flexibility and associated cognitive cost. A widely accepted dichotomy distinguishes between a cheap but rigid model-free system and a flexible but costly model-based system. Typically, humans use a hybrid of both types of decision-making depending on environmental demands. However, children's use of a model-based system during decision-making has not yet been shown. While prior developmental work has identified simple building blocks of model-based reasoning in young children (1–4 years old), there has been little evidence of this complex cognitive system influencing behavior before adolescence. Here, by using a modified task to make engagement in cognitively costly strategies more rewarding, we show that children aged 5–11-years (N = 85), including the youngest children, displayed multiple indicators of model-based decision making, and that the degree of its use increased throughout childhood. Unlike adults (N = 24), however, children did not display adaptive arbitration between model-free and model-based decision-making. Our results demonstrate that throughout childhood, children can engage in highly sophisticated and costly decision-making strategies. However, the flexible arbitration between decision-making strategies might be a critically late-developing component in human development.     

Unvaxxed and unafraid: Unvaccinated Americans perceive less disease risk than do vaccinated Americans

Is disease risk perception accurately calibrated among the unvaccinated? People shift their attitudes to rationalize their choices, so those who choose to be unvaccinated may be motivated to feel less at risk. In three studies (total N = 1446), we asked Americans how worried they were about catching/spreading influenza and COVID-19 and whether they were vaccinated against those diseases. Unvaccinated participants felt less at risk of catching/spreading the diseases they were unvaccinated against than vaccinated participants. For instance, unvaccinated participants felt ∼24% less at risk of catching/spreading COVID-19 and had ∼28% stronger intention to engage in activities that carried a high risk of COVID-19 transmission (Study 3). Overall, those who choose to be the most vulnerable to disease feel and act the least vulnerable.