Previous research consistently reported that subjects that were exclusively breastfed (eBF) vs. not-exclusively breastfed (neBF) during infancy (0-6 months) showed increased scores of general intelligence measures (e.g., the intelligence quotient). However, the existent literature largely neglected whether breastfeeding also affects specific cognitive processes, such as attention and working memory (WM) capacity. We tested whether eBF vs. neBF subjects showed performance differences in relation to these two core cognitive functions. The Attention Network Test (ANT), to measure alerting, orienting, and conflict, and the Change Colour Task (CCT), to measure visuospatial WM capacity, were administered to 144 participants divided according to age (6-, 10-, and 18-year-old participants) and breastfeeding (eBF or neBF during 0-6 months of life). Importantly, the sub-groups were homogenous in terms of maternal education, a factor potentially affecting the relation between breastfeeding and cognition. While we found increased performance as a function of participants' age in both tasks, we failed to observe effects related to breastfeeding, as evidenced by Bayesian analyses. These findings highlight for the first time that the pattern of nutrition provided during early infancy does not appear to affect the development of attention and WM capacity, at least starting from the age considered in the present study.

Remote methods for data collection allow us to quickly collect large amounts of data, offering several advantages as compared to in-lab administration. We investigated the applicability of an online assessment of motor, cognitive, and communicative development in 4-month-old infants based on several items of the Bayley Scales of Infant Development, 3rd edition (BSID-III). We chose a subset of items which were representative of the typical developmental achievements at 4 months of age and that we could administer online with the help of the infant's caregiver using materials which were easily available at home. Results showed that, in a sample of infants tested live (N = 18), the raw scores of the BSID-III were significantly correlated with the raw scores of a subset of items corresponding to those administered to a sample of infants tested online (N = 53). Moreover, for the "online" participants, the raw scores of the online assessment did not significantly differ from the corresponding scores of the "live" participants. These findings suggest that the online assessment was to some extent comparable to the live administration of the same items, thus representing a viable opportunity to remotely evaluate infant development when in-person assessment is not possible.

Although both human and non-human animals, in everyday life, deal with risky decisions in a social environment, few studies investigated how social dimension influences risk preferences (i.e., if consequences on others feeds back over own choice). Here, we assessed whether the presence of a conspecific, acting as a potential competitor for the same food resource, influenced risky decision-making in male rats. Subjects received a series of choices between a safe option (always yielding a small yet optimal reward, solely to itself) and a risky option (yielding a larger but suboptimal reward, one third of times to itself and two third of times delivered to the other half cage); rats were tested twice, both alone and paired with a conspecific, recipient of own-lost food and hence acting as potential competitor. Results showed that focal subjects were more risk-prone when paired with a conspecific than when tested alone. However, rats exhibited also a higher motivational conflict with a competing bystander present than alone: data suggest that the primary drive was to increase "own" food rather than either a competitive or prosocial tendency. Overall, for rats tested in a risky-choice task, a competitive social context increased the salience and attractiveness of larger food outcomes, as observed in humans and great apes. This led to the economically irrational response of selecting the "binge-but-risky" option, notwithstanding uncertainty about the actual recipient of such food.

Sleep is an essential function of human life, underlying both biological and cultural processes. Dramatic changes in sleep occur during infancy, in terms of night awakenings, which tend to diminish over time, and day/night sleep duration, with newborns sleeping up to 16-17 h per day and gradually decreasing to 9-13 h between 6 and 11 months of age. Remarkably, research indicates that changes in infant sleep are in interaction with important acquisitions in other domains of child development. In the present study, we aimed at investigating concurrent and longitudinal relations between sleep and cognitive maturation during infancy, by collecting data on 156 infants at 4 and 8 months of age. Infants' sleep was assessed through the Brief Infant Sleep Questionnaire (BISQ; Sadeh, 2004), whereas cognitive maturation was evaluated using the Developmental Profile(TM) 3 (Alpern 2007). We also examined infants' language understanding through the short form of the Italian version of the MacArthur-Bates Communicative Development Inventory (MCDI-SF): Words and Gestures (Caselli, Bello, Rinaldi, Stefanini, & Pasqualetti, 2015; Fenson et al., 2000). Finally, information about infants' temperament and maternal practices potentially relevant for sleep quality, such as the use of a pacifier at nighttime, co-sleeping and exclusive breastfeeding, was detected. Results showed that night and day sleep were differently related to infants' development at 4 and 8 months of age, but there were no robust longitudinal relationships.

How animals respond to novelty may have important outcomes in terms of fitness. On the one hand, aversion to novel stimuli may reduce the risks of consuming potentially toxic food or encountering predators. On the other hand, the propensity to approach novel stimuli may allow individuals to explore novel food sources and more flexibly adapt to novel challenges. Different species and individuals may find different ways to balance the costs and benefits that novelty posits. To date, however, little is known on how response to novel food varies across individuals of the same species depending on their previous experience with novelty, risk attitude and presence of higher-ranking conspecifics. In this study, we assessed individual variation in response to novel food by testing captive capuchin monkeys (Sapajus spp.) in an unconstrained social context, where all individuals in a group were able to access the testing area on a voluntary basis. We provided familiar and novel food to 23 study subjects belonging to four social groups differing in (i) previous experience with novel food, (ii) risk attitude (as assessed by a previous risky decision-making task), and (iii) dominance rank. We predicted that, as individuals may generalize their previous experience to novel contexts, those with more previous experience with novel food would be less neophobic than those with less experience. Moreover, if neophobia is a facet of the individual's risk attitude, we predicted that more risk-prone individuals would be less neophobic than less risk-prone ones. Finally, individuals might flexibly modify their food choices according to the presence of conspecifics; in this respect, we predicted that, in response to monopolization of preferred resources by higher-ranking individuals, lower-ranking individuals would prefer familiar over novel food in the absence of higher-ranking individuals, but would modify their preference in favor of novel food in the presence of higher-ranking individuals. None of these predictions were supported by our results. We observed, however, that neophobia, measured as the latency to retrieve a food item, was more pronounced in lower-ranking than higher-ranking individuals, and that males showed a generally stronger bias than females toward a quicker retrieval of familiar food.

Recensione del film "Il pianeta delle scimmie" per il numero speciale sulla Distopia nell'Almanacco della Scienza del CNR

Baby-led weaning is an approach to complementary feeding that emphasizes an infant's ability to self-feed rather than being spoon fed, and to eat minimally-processed foods rather than puréed foods. This study aimed to investigate the variability in infant feeding practices and the possible association with developmental milestones in an Italian population. A sample of 1245 mothers of 6-12 month-old infants completed an online survey about complementary feeding and their infant's attainment of developmental milestones. Infants' eating of family food was positively related to self-feeding and to a lower consumption of puréed foods. As in previous studies in the UK and New Zealand, a baby-led weaning style was positively associated with breastfeeding, exposure to complementary foods around six months of age, earlier exposure to both finger and family foods, and higher interest in family food and shared family meals. Infants who were introduced to solid foods using a baby-led weaning approach were more likely to have met important developmental milestones; when controlling for covariates, percentage of family feeding was positively associated with sitting unsupported at an earlier age and a low spoon-feeding style was associated with crawling at an earlier age. These data suggest that baby-led weaning should be defined more comprehensively. Moreover, its potential influence on developmental domains beyond diet and eating behavior warrants future targeted exploration.

The timing and strategy with which parents first introduce their infants to solid foods may be an important predictor of subsequent developmental outcomes. Recent years have seen a decline in the prevalence of traditional parent-led feeding of soft, puréed food and a rise in the prevalence of infant-led complementary feeding. Although there has been some research espousing the benefits of infant-led complementary feeding for improving food fussiness and self-regulation, there has been little exploration of this approach that may impact on other developmental outcomes in children. The current study explores whether aspects of the infant-led approach, specifically the child eating unaided and consuming finger foods and eating with the family, are related to child language outcomes. One hundred thirty one parents of children aged 8-24 months completed questionnaires about their approach to complementary feeding, their current feeding practices, their child's experiences with family foods and child language comprehension/production. The findings suggest that an approach to complementary feeding which promotes infant autonomy in feeding (i.e., eating finger foods rather than puréed foods) and consuming more family foods is related to more advanced child language production and comprehension. Specifically, the prevalence of eating family foods mediated the relationship between eating unaided at the onset of the complementary feeding period and later language outcomes. This study is the first to find a significant relationship between different approaches to introducing solid foods and child language outcomes and these findings highlight the potential for different complementary feeding approaches to influence behaviour beyond mealtimes.

We addressed two different aspects of indirect reciprocity in tufted capuchin monkeys (Sapajus spp.) studying two common cooperative behaviours, grooming and food sharing. In an observational study, we tested whether capuchin monkeys were more likely to groom an individual that had just groomed a group mate than an individual that had not groomed anybody. In an experimental study, we tested whether capuchin monkeys were more likely to share their food with a partner when in the presence of a bystander (or of an image of the eyes of a conspecific) than when alone with their partner. In the observational study, we found an increase in the likelihood of receiving grooming after giving grooming, but this effect seemed to depend on social facilitation rather than on indirect reciprocity, as we found a similar effect after receiving (rather than giving) grooming. In the experimental study, the presence of a bystander or of an image of eyes did not affect the amount of food transferred to a group mate. Overall, these results suggest capuchin monkeys do not engage in indirect reciprocity.

Do we have any valid reasons to affirm that non-human primates display economic behaviour in a sufficiently rich and precise sense of the phrase? To address this question, we have to develop a set of criteria to assess the vast array of experimental studies and field observations on individual cognitive and behavioural competences as well as the collective organization of non-human primates. We review a sample of these studies and assess how they answer to the following four main challenges. (i) Do we see any economic organization or institutions emerge among groups of non-human primates? (ii) Are the cognitive abilities, and often biases, that have been evidenced as underlying typical economic decision-making among humans, also present among non-human primates? (iii) Can we draw positive lessons from performance comparisons among primate species, humans and non-humans but also across non-human primate species, as elicited by canonical game-theoretical experimental paradigms, especially as far as economic cooperation and coordination are concerned? And (iv) in which way should we improve models and paradigms to obtain more ecological data and conclusions? Articles discussed in this paper most often bring about positive answers and promising perspectives to support the existence and prevalence of economic behaviours among non-human primates. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Money represents a cornerstone of human modern economies and how money emerged as a medium of exchange is a crucial question for social sciences. Although non-human primates have not developed monetary systems, they can estimate, combine and exchange tokens. Here, we evaluated quantity-quality trade-offs in token choices in tufted capuchin monkeys as a first step in the investigation of the generalizability of tokens as reinforcers, which is a potentially relevant factor underlying the emergence of money in humans. We measured capuchins' exchange preferences when they were repeatedly provided with 10 units of three token types yielding food combinations varying in quantity and quality. Overall, capuchins maximized their quantitative payoff, preferring tokens associated with a higher food amount, rather than showing violations of rationality. However, some individuals did not maximize their qualitative payoff, possibly because of conditional valuation effects or owing to the choice overload phenomenon, according to which too many options reduce the accuracy of choice. Our study supports the importance of comparative research to finely analyse the multiple components shaping the economic behaviours of other species, possibly to achieve a more comprehensive, evolutionary- and ecologically based understanding of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Principles of economics predict that the costs associated with obtaining rewards can influence choice. When individuals face choices between a smaller, immediate option and a larger, later option, they often experience opportunity costs associated with waiting for delayed rewards because they must forego the opportunity to make other choices. We evaluated how reducing opportunity costs affects delay tolerance in capuchin monkeys. After choosing the larger option, in the High cost condition, subjects had to wait for the delay to expire, whereas in the Low cost different and Low cost same conditions, they could perform a new choice during the delay. To control for the effect of intake rate on choices, the Low cost same condition had the same intake rate ratio as the High cost condition. We found that capuchins attended both to intake rates and to opportunity costs. They chose the larger option more often in the Low cost different and Low cost same conditions than in the High cost condition, and more often in the Low cost different condition than in the Low cost same condition. Understanding how non-human primates represent and use costs in making decisions not only helps to develop theoretical frameworks to explain their choices but also addresses similarities with and differences from human decision-making. These outcomes provide insights into the origins of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

In this work, we focused on testing one of the proximal mechanisms that have been proposed to explain cooperative behaviours such as the mutual exchange of goods and services in non-human primates. Specifically, we tested 'calculated reciprocity', according to which animals exchange food with conspecifics driven by the expectation of a return of the favour. We tested pairs of tufted capuchin monkeys (Sapajus spp.), a species known to readily exchange food, in three different experimental conditions. In the first condition, the partner, after receiving food from the subject in a first test phase, could reciprocate during a second test phase (Reciprocity). In the second condition, the partner did not have the possibility to reciprocate (Control). In the third condition, the experimenter gave the subject a quantity of food proportional to what the subject had given to the partner (Pseudoreciprocity). There was no difference in the amount of food transferred from the subject to the partner among the three experimental conditions. However, in the Pseudoreciprocity condition, capuchin monkeys increased the amount of food shared along successive test sessions. These findings suggest that the expectation of reciprocation did not motivate capuchin monkeys to share their food, although they were able to learn that sharing can lead to a reward.

We review and analyze evidence for an evolutionary rooting of human economic behaviors and organization in non-human primates. Rather than focusing on the direct application of economic models that a priori account for animal decision behavior, we adopt an inductive definition of economic behavior in terms of the contribution of individual cognitive capacities to the provision of resources within an exchange structure. We spell out to what extent non-human primates' individual and strategic decision behaviors are shared with humans. We focus on the ability to trade, through barter or token-mediated exchanges, as a landmark of an economic system among members of the same species. It is an open question why only humans have reached a high level of economic sophistication. While primates have many of the necessary cognitive abilities (symbolic and computational) in isolation, one plausible issue we identify is the limits in exerting cognitive control to combine several sources of information. The difference between human and non-human primates' economies might well then be in degree rather than kind.

Humans have generally been considered risk averse for gains. Yet, growing evidence shows that risk preferences may change across reward currencies and depend on the type of tasks used to measure them. Here, we examined how context affects human risk preferences to shed light on the psychological mechanisms underlying human decision-making under risk. Participants were presented with a descriptive risky choice task involving repeated choices between real options and they were provided with trial-by-trial feedback. We manipulated the type of reward and, for the first time, the format of the choice stimuli. Options were either 2D computer-based images or concrete 3D objects, and participants received food or money as reward. First, we found that participants were more risk-seeking for food compared to money, suggesting that people treat money differently from consumable rewards. Second, we found that people were more risk-seeking when they made choices between concrete 3D objects than between 2D computer-based images. Our results strengthened the evidence that human choice patterns may change depending on the context and, for the first time, showed that the format of the choice stimuli does affect risk preferences, an important consideration for future research.

We aimed to longitudinally examine how symbolic distancing affects preschool children's delay tolerance in a delay choice task. We presented children with choices between a smaller immediate reward and a larger delayed reward in conditions with either symbolic stimuli or edible rewards. Overall, symbolic distancing modulated children's delay tolerance. In particular, whereas in the first phase (T1: 3- and 4-year-olds) children presented with edible rewards chose the larger option more often than children presented with symbolic stimuli, in the second phase (T2: 5- and 6-year-olds), there was no significant difference between children presented with symbolic stimuli and those presented with edible rewards. These results are discussed by examining how children's delay tolerance changes during the development and comparing children to adult humans in a similar task.

Money is a cultural artefact with a central role in human society. Here, we investigated whether some features of money may be traced back to the exchange habits of nonhuman animals, capitalizing on their ability to flexibly use tokens in different domains. In Experiment 1, we evaluated whether capuchins can recognize token validity. Six subjects were required to exchange with the experimenter valid/familiar tokens, valid/unfamiliar tokens, invalid tokens, and no-value items. They first exchanged a similar number of valid/familiar and valid/unfamiliar tokens, followed by exchanges of invalid tokens and no-value items. Thus, as humans, capuchins readily recognized token validity, regardless of familiarity. In Experiment 2, we further evaluated the flexibility of the token-food association by assessing whether capuchins could engage in reverse food-token exchanges. Subjects spontaneously performed chains of exchanges, in which a food item was exchanged for a token, and then the token was exchanged for another food. However, performance was better as the advantage gained from the exchange increased. Overall, capuchins recognized token validity and successfully engaged in chains of reverse and direct exchanges. This suggests that--although nonhuman animals are far from having fully-fledged monetary systems--for capuchins tokens share at least some features with human money.

Executive function (EF) is a heterogeneous construct widely used to refer to a conspicuous number of higher-order cognitive processes devoted to the monitoring and control of thoughts and actions. EF is generally regarded as being particularly important in novel or unfamiliar situations in which thoughtful and cautious behavior, instead of automatic and impulsive response, is required (Diamond 2013). The functioning of executive processes is thought to rely on the prefrontal cortex (PFC) in both humans and non-human animals, regardless of the anatomical variations existing across different species (Robbins 2000).