Measurement invariance of the moral vitalism scale across 28 cultural groups.

Moral vitalism refers to a tendency to view good and evil as actual forces that can influence people and events. The Moral Vitalism Scale had been designed to assess moral vitalism in a brief survey form. Previous studies established the reliability and validity of the scale in US-American and Australian samples. In this study, the cross-cultural comparability of the scale was tested across 28 different cultural groups worldwide through measurement invariance tests. A series of exact invariance tests marginally supported partial metric invariance, however, an approximate invariance approach provided evidence of partial scalar invariance for a 5-item measure. The established level of measurement invariance allows for comparisons of latent means across cultures. We conclude that the brief measure of moral vitalism is invariant across 28 cultures and can be used to estimate levels of moral vitalism with the same precision across very different cultural settings.

Explaining illness with evil: pathogen prevalence fosters moral vitalism.

Pathogens represent a significant threat to human health leading to the emergence of strategies designed to help manage their negative impact. We examined how spiritual beliefs developed to explain and predict the devastating effects of pathogens and spread of infectious disease. Analysis of existing data in studies 1 and 2 suggests that moral vitalism (beliefs about spiritual forces of evil) is higher in geographical regions characterized by historical higher levels of pathogens. Furthermore, drawing on a sample of 3140 participants from 28 countries in study 3, we found that historical higher levels of pathogens were associated with stronger endorsement of moral vitalistic beliefs. Furthermore, endorsement of moral vitalistic beliefs statistically mediated the previously reported relationship between pathogen prevalence and conservative ideologies, suggesting these beliefs reinforce behavioural strategies which function to prevent infection. We conclude that moral vitalism may be adaptive: by emphasizing concerns over contagion, it provided an explanatory model that enabled human groups to reduce rates of contagious disease.

The development of human social learning across seven societies.

Social information use is a pivotal characteristic of the human species. Avoiding the cost of individual exploration, social learning confers substantial fitness benefits under a wide variety of environmental conditions, especially when the process is governed by biases toward relative superiority (e.g., experts, the majority). Here, we examine the development of social information use in children aged 4-14 years (n = 605) across seven societies in a standardised social learning task. We measured two key aspects of social information use: general reliance on social information and majority preference. We show that the extent to which children rely on social information depends on children's cultural background. The extent of children's majority preference also varies cross-culturally, but in contrast to social information use, the ontogeny of majority preference follows a U-shaped trajectory across all societies. Our results demonstrate both cultural continuity and diversity in the realm of human social learning.

Chimpanzees (Pan troglodytes) and human children (Homo sapiens) know when they are ignorant about the location of food.

Over the last decade, the metacognitive abilities of nonhuman primates and the developmental emergence of metacognition in children have become topics of increasing research interest. In the current study, the performance of three adult chimpanzees (Pan troglodytes; Experiment 1) and forty-four 3.5- and 5.5-year-old human children (Experiment 2) was assessed on a behavioral search paradigm designed to assess metacognition. Subjects either directly observed the baiting of a large reward into one cup among an array of four, or had the baiting occluded from their view. In half of the trials, subjects were also presented with an additional distinctive cup that was always visibly baited with a small reward. This cup allowed subjects the opportunity to escape from making a guess about the location of the bigger reward. All three chimpanzees and both age groups of children selected the escape cup more often when the baiting of the large reward was concealed, compared to when it was visible. This demonstrates that both species can selectively choose a guaranteed smaller reward when they do not know the location of a larger reward and provides insight into the development of metacognition.

Preschool children favor copying a successful individual over an unsuccessful group.

The human aptitude for imitation and social learning underpins our advanced cultural practices. While social learning is a valuable evolutionary survival strategy, blind copying does not necessarily facilitate survival. Copying from the majority allows individuals to make rapid judgments on the value of a trait, based on its frequency. This is known as the majority bias: an individual's tendency to copy the behavior elicited by the largest number of individuals in a population. An alternative approach is to follow those who are the most proficient. While there is evidence that children do show both processes, no study has directly pitted them against each other. To do this, in the current experiment 36 children aged between 4 and 5 years watched live actors demonstrate, as a group or individually, how to open novel puzzle boxes. Children exhibited a bias to the majority when group and individual methods were successful, but favored the individual if the group method was unsuccessful. Affiliating children with the unsuccessful majority group did not impact on this pattern.

Groups' actions trump injunctive reaction in an incidental observation by young children.

Children's ability to use social information to direct their behavior is key to their survival and development. However, in observing adult behavior, children are confronted with multiple forms of social information that may vary in reliability and adaptiveness. Two of the most well established biases influencing human behavior are: (1) following the majority (majority influence or conformity); and (2) the use of emotional signals. The current experiment aimed to evaluate how children respond when both information about the majority behavior of a group (descriptive norm) and attitudes of the group towards a behavior (injunctive norm, expressed through an emotional reaction) are present and what happens when they are in conflict. We used a method designed to mimic the manner in which children might observe group members' behavior during development. Novel apparatuses were constructed for which there were two discrete actions that could be performed to retrieve a reward. Three-year-olds observed four adults demonstrating one set of actions, followed by a fifth adult who presented an alternative set of actions. The first four adults' injunctive responses to this fifth adult's actions were manipulated between-groups: positive, negative, or neutral. It was found that children preferred to copy the majority action, regardless of the injunctive reaction of the group. We argue that this affirms the adaptive utility of copying the majority.

Direct cost does not impact on young children's spontaneous helping behavior.

The propensity of humans to engage in prosocial behavior is unlike that of any other species. Individuals will help others even when it comes at a cost to themselves, and even when the others are complete strangers. However, to date, scant empirical evidence has been forthcoming on young children's altruistic tendencies. To investigate this 45 4-year-olds were presented with a task in which they had opportunity to help an adult confederate retrieve a reward from a novel box. In a control condition children were given no information about the effect of potential helping behavior. Alternatively they were informed that helping would either cost them (i.e., they would miss out on getting the reward) or benefit them (i.e., they would get the reward). It was hypothesized that children would be less likely, and slower, to help in the cost condition, compared to the other two conditions. This hypothesis was not supported: children across all conditions provided help at near ceiling levels.

Inferential reasoning by exclusion in children (Homo sapiens).

The cups task is the most widely adopted forced-choice paradigm for comparative studies of inferential reasoning by exclusion. In this task, subjects are presented with two cups, one of which has been surreptitiously baited. When the empty cup is shaken or its interior shown, it is possible to infer by exclusion that the alternative cup contains the reward. The present study extends the existing body of comparative work to include human children (Homo sapiens). Like chimpanzees (Pan troglodytes) that were tested with the same equipment and near-identical procedures, children aged three to five made apparent inferences using both visual and auditory information, although the youngest children showed the least-developed ability in the auditory modality. However, unlike chimpanzees, children of all ages used causally irrelevant information in a control test designed to examine the possibility that their apparent auditory inferences were the product of contingency learning (the duplicate cups test). Nevertheless, the children's ability to reason by exclusion was corroborated by their performance on a novel verbal disjunctive syllogism test, and we found preliminary evidence consistent with the suggestion that children used their causal-logical understanding to reason by exclusion in the cups task, but subsequently treated the duplicate cups information as symbolic or communicative, rather than causal. Implications for future comparative research are discussed.

Inferential reasoning by exclusion in great apes, lesser apes, and spider monkeys.

Using the cups task, in which subjects are presented with limited visual or auditory information that can be used to deduce the location of a hidden reward, Call (2004) found prima facie evidence of inferential reasoning by exclusion in several great ape species. One bonobo (Pan paniscus) and two gorillas (Gorilla gorilla) appeared to make such inferences in both the visual and auditory domains. However, common chimpanzees (Pan troglodytes) were successful only in the visual domain, and Bornean orangutans (Pongo pygmaeus) in neither. The present research built on this paradigm, and Experiment 1 yielded prima facie evidence of inference by exclusion in both domains for two common chimpanzees, and in the visual domain for two Sumatran orangutans (Pongo abelii). Experiments 2 and 3 demonstrated that two specific associative learning explanations could not readily account for these results. Because an important focus of the program of research was to assess the cognitive capacities of lesser apes (family Hylobatidae), we modified Call's original procedures to better suit their attentional and dispositional characteristics. In Experiment 1, testing was also attempted with three gibbon genera (Symphalangus, Nomascus, Hylobates), but none of the subjects completed the standard task. Further testing of three siamangs (Symphalangus syndactylus) and a spider monkey (Ateles geoffroyi) using a faster method yielded prima facie evidence of inferential reasoning by exclusion in the visual domain among the siamangs (Experiment 4).

How great is great ape foresight?

Osvath and Osvath (Anim Cogn 11: 661-674, 2008) report innovative studies with two chimpanzees and one orangutan that suggest some capacity to select and keep a tool for use about an hour later. This is a welcome contribution to a small, but rapidly growing, field. Here we point out some of the weaknesses in the current data and caution the interpretation the authors advance. It is not clear to what extent the apes really engaged in any foresight in these studies.

The evolution of primate visual self-recognition: evidence of absence in lesser apes.

Mirror self-recognition typically emerges in human children in the second year of life and has been documented in great apes. In contrast to monkeys, humans and great apes can use mirrors to inspect unusual marks on their body that cannot be seen directly. Here we show that lesser apes (family Hylobatidae) fail to use the mirror to find surreptitiously placed marks on their head, in spite of being strongly motivated to retrieve directly visible marks from the mirror surface itself and from their own limbs. These findings suggest that the capacity for visual self-recognition evolved in a common ancestor of all great apes after the split from the line that led to modern lesser apes approximately 18 Myr ago. They also highlight the potential of a comparative approach for identifying the neurological and genetic underpinnings of self-recognition and other higher cognitive faculties.

Do chimpanzees (Pan troglodytes) and 2-year-old children (Homo sapiens) understand double invisible displacement?

Chimpanzees (Pan troglodytes) and young children (Homo sapiens) have difficulty with double invisible displacements in which an object is hidden in two nonadjacent boxes in a linear array. Experiment 1 eliminated the possibility that chimpanzees' previous poor performance was due to the hiding direction of the displacement device. As in Call (2001), subjects failed double nonadjacent displacements, showing a tendency to select adjacent boxes. In Experiments 2 and 3, chimpanzees and 24-month-old children were tested on a new adaptation of the task in which four hiding boxes were presented in a diamond-shaped array on a vertical plane. Both species performed above chance on double invisible displacements using this format, suggesting that previous poor performance was due to a response bias or inhibition problem rather than a fundamental limitation in representational capacity.

Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.

Imitation recognition in a captive chimpanzee (Pan troglodytes).

This study investigated the ability of a captive chimpanzee (Pan troglodytes) to recognise when he is being imitated. In the experimental condition of test 1a, an experimenter imitated the postures and behaviours of the chimpanzee as they were being displayed. In three control conditions the same experimenter exhibited (1) actions that were contingent on, but different from, the actions of the chimpanzee, (2) actions that were not contingent on, and different from, the actions of the chimpanzee, or (3) no action at all. The chimpanzee showed more "testing" sequences (i.e., systematically varying his actions while oriented to the imitating experimenter) and more repetitive behaviour when he was being imitated, than when he was not. This finding was replicated 4 months later in test 1b. When the experimenter repeated the same actions she displayed in the experimental condition of test 1a back to the chimpanzee in test 2, these actions now did not elicit those same testing sequences or repetitive behaviours. However, a live imitation condition did. Together these results provide the first evidence of imitation recognition in a nonhuman animal.

Do dogs (Canis familiaris) understand invisible displacement?

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object ended up adjacent to the target box after the displacement. These results suggest that the search behavior of dogs was guided by simple associative rules rather than mental representation of the object's past trajectory. In contrast, Experiment 5 found that on the same task, 18- and 24-month-old children showed no disparity between trials in which the displacement device was adjacent or nonadjacent to the target box.