Tanya Broesch

Early false-belief understanding in traditional non-Western societies

The psychological capacity to recognize that others may hold and act on false beliefs has been proposed to reflect an evolved, species-typical adaptation for social reasoning in humans; however, controversy surrounds the developmental timing and universality of this trait. Cross-cultural studies using elicited-response tasks indicate that the age at which children begin to understand false beliefs ranges from 4 to 7 years across societies, whereas studies using spontaneous-response tasks with Western children indicate that false-belief understanding emerges much earlier, consistent with the hypothesis that false-belief understanding is a psychological adaptation that is universally present in early childhood. To evaluate this hypothesis, we used three spontaneous-response tasks that have revealed early false-belief understanding in the West to test young children in three traditional, non-Western societies: Salar (China), Shuar/Colono (Ecuador) and Yasawan (Fiji). Results were comparable with those from the West, supporting the hypothesis that false-belief understanding reflects an adaptation that is universally present early in development.

Cultural Variations in Children's Mirror Self-Recognition

Western children first show signs of mirror self-recognition (MSR) from 18 to 24 months of age, the benchmark index of emerging self-concept. Such signs include self-oriented behaviors while looking at the mirror to touch or remove a mark surreptitiously placed on the child’s face. The authors attempted to replicate this finding across cultures using a simplified version of the classic “mark test.” In Experiment 1, Kenyan children (N = 82, 18 to 72 months old) display a pronounced absence of spontaneous self-oriented behaviors toward the mark. In Experiment 2, the authors tested children in Fiji, Saint Lucia, Grenada, and Peru (N = 133, 36 to 55 months old), as well as children from urban United States and rural Canada. As expected from existing reports, a majority of the Canadian and American children demonstrate spontaneous self-oriented behaviors toward the mark. However, markedly fewer children from the non-Western rural sites demonstrate such behaviors. These results suggest that there are profound cross-cultural differences in the meaning of the MSR test, questioning the validity of the mark test as a universal index of self-concept in children’s development.

Prosocial behavior leads to happiness in a small-scale rural society.

Humans are extraordinarily prosocial, and research conducted primarily in North America indicates that giving to others is emotionally rewarding. To examine whether the hedonic benefits of giving represent a universal feature of human behavior, we extended upon previous cross-cultural examinations by investigating whether inhabitants of a small-scale, rural, and isolated village in Vanuatu, where villagers have little influence from urban, Western culture, survive on subsistence farming without electricity, and have minimal formal education, report or display emotional rewards from engaging in prosocial (vs. personally beneficial) behavior. In Study 1, adults were randomly assigned to purchase candy for either themselves or others and then reported their positive affect. Consistent with previous research, adults purchasing goods for others reported greater positive emotion than adults receiving resources for themselves. In Study 2, 2- to 5-year-old children received candy and were subsequently asked to engage in costly giving (sharing their own candy with a puppet) and non-costly giving (sharing the experimenters candy with a puppet). Emotional expressions were video-recorded during the experiment and later coded for happiness. Consistent with previous research conducted in Canada, children displayed more happiness when giving treats away than when receiving treats themselves. Moreover, the emotional rewards of giving were largest when children engaged in costly (vs. non-costly) giving. Taken together, these findings indicate that the emotional rewards of giving are detectable in people living in diverse societies and support the possibility that the hedonic benefits of generosity are universal.

Prosody in Infant-Directed Speech Is Similar across Western and Traditional Cultures.

When speaking to infants, adults typically alter the acoustic properties of their speech in a variety of ways compared with how they speak to other adults; for example, they use higher pitch, increased pitch range, more pitch variability, and slower speech rate. Research shows that these vocal changes happen similarly across industrialized populations, but no studies have carefully examined basic acoustic properties of infant-directed (ID) speech in traditional societies. Moreover, some scholars have suggested that ID speech is culturally specific and does not exist in some small-scale societies. We examined fundamental frequency (F0) production and speech rate in mothers speaking to both infants and adults in three cultures: Fijians, Kenyans, and North Americans. In all three cultures, speakers used higher F0 when speaking to infants relative to when speaking to other adults, and they also used significantly greater F0 variation and fewer syllables per second. Previous research has found that American mothers tend to use higher pitch than do mothers from other cultures, but when maternal education was controlled in the current study, we did not find a significant difference in average pitch across our three populations. This is the first research systematically comparing spontaneous ID and adult-directed speech prosody between Western and traditional societies, and it is consistent with a large body of evidence showing similar acoustic patterns in ID speech across industrialized populations.

Why Two-Year-Olds Fail to Learn Gestures as Object Labels: Evidence from Looking Time and Forced-Choice Measures

The range of symbols that children treat as object names narrows over the course of development as children accrue more experience with and exposure to language. By two years of age, children no longer treat gestures as object labels. Here we investigate the source of this new-found failure and ask whether it stems primarily from a failure to form associations between gestures and their referents, as opposed to a failure to interpret these associations as referential. To explore these possibilities, we tested word versus gesture learning in a paradigm consisting of both a preferential looking task (designed to detect implicit associations) and a forced-choice task (designed to index explicit symbol-to-referent mapping). Our findings reveal that unlike two-year-olds in the word condition, two-year-olds in the gesture condition failed to demonstrate associations between gestures and objects in either task, suggesting that they did not form associative links between gestures and their intended referent. Importantly, those who did exhibit associations during preferential looking were also more likely to demonstrate successful learning of gestures in the forced-choice task. In contrast, 18-month-olds readily formed associations between gestures and objects. We conclude that the decline in receptivity to gestural labels during the second year is due to a failure to form reliable associations between gestures and their referents.

Variation is the universal: making cultural evolution work in developmental psychology

Culture is a human universal, yet it is a source of variation in human psychology, behaviour and development. Developmental researchers are now expanding the geographical scope of research to include populations beyond relatively wealthy Western communities. However, culture and context still play a secondary role in the theoretical grounding of developmental psychology research, far too often. In this paper, we highlight four false assumptions that are common in psychology, and that detract from the quality of both standard and cross-cultural research in development. These assumptions are: (i) the universality assumption, that empirical uniformity is evidence for universality, while any variation is evidence for culturally derived variation; (ii) the Western centrality assumption, that Western populations represent a normal and/or healthy standard against which development in all societies can be compared; (iii) the deficit assumption, that population-level differences in developmental timing or outcomes are necessarily due to something lacking among non-Western populations; and (iv) the equivalency assumption, that using identical research methods will necessarily produce equivalent and externally valid data, across disparate cultural contexts. For each assumption, we draw on cultural evolutionary theory to critique and replace the assumption with a theoretically grounded approach to culture in development. We support these suggestions with positive examples drawn from research in development. Finally, we conclude with a call for researchers to take reasonable steps towards more fully incorporating culture and context into studies of development, by expanding their participant pools in strategic ways. This will lead to a more inclusive and therefore more accurate description of human development. This article is part of the theme issue ‘Bridging cultural gaps: interdisciplinary studies in human cultural evolution’.

Learning From Others: Selective Requests by 3-Year-Olds of Three Cultures:

Humans are unique in their propensity to intentionally instruct and subsequently learn a wide range of information from others. We investigated when and how young children become socially resourceful in using others’ expertise, and whether the early propensity to request for help varies across diverse societies. We tested and compared 44 two- to four-year-old children growing up in urban United States and Japan, and rural Canada. Children were faced with two experimenters who demonstrated different abilities (successful vs. unsuccessful) in a toy retrieving task. We measured children’s propensity to request for help and the relative selectivity of requests to one experimenter over another. Results show significant cross-cultural differences. U.S. children’s request behavior differed significantly from the other two societies on three of the four measures. Specifically, U.S. children requested more overall, whereas Japanese children ceased manipulation (“give up”), and Canadian children continued to try on their own. Only the U.S. children show clear selective requests to the successful experimenter. On the last measure (gaze behavior), the U.S. and Canadian children look more to the successful model during the test phase than the unsuccessful model. These findings have implications for social learning research as well as the generalizability of developmental science.

Evidence for proactive and reactive helping in two- to five-year-olds from a small-scale society

Humans are unique in their propensity for helping. Not only do we help others in need by reacting to their requests, we also help proactively by assisting in the absence of a request. Proactive helping requires the actor to detect the need for help, recognize the intention of the other, and remedy the situation. Very little is known about the development of this social phenomenon beyond an urban, industrialized setting. We examined helping in nineteen two- to five-year old children in small-scale rural villages of Vanuatu. In the experimental condition, the intentions of the experimenter were made salient, whereas in the control condition they were ambiguous. Children helped more often in the experimental compared to the control condition, suggesting that the propensity to monitor others’ goals and act accordingly can be detected in different cultural contexts.