Hearing water temperature: Characterizing the development of nuanced perception of sound sources.

Without conscious thought, listeners link events in the world to sounds they hear. We study one surprising example: Adults can judge the temperature of water simply from hearing it being poured. We test the development of the ability to hear water temperature, with the goal of informing developmental theories regarding the origins and cognitive bases of nuanced sound source judgments. We first confirmed that adults accurately distinguished the sounds of hot and cold water (pre-registered Experiments. 1, 2; total N = 384), even though many were unaware or uncertain of this ability. By contrast, children showed protracted development of this skill over the course of middle childhood (Experiments. 2, 3; total N = 178). In spite of accurately identifying other sounds and hot/cold images, older children (7-11 years) but not younger children (3-6 years) reliably distinguished the sounds of hot and cold water. Accuracy increased with age; 11-year old's performance was similar to adults. Adults also showed individual differences in accuracy that were predicted by their amount of prior relevant experience (Experiment 1). Experience may similarly play a role in children's performance; differences in auditory sensitivity and multimodal integration may also contribute to young children's failures. The ability to hear water temperature develops slowly over childhood, such that nuanced auditory information that is easily and quickly accessible to adults is not available to guide young children's behavior. HIGHLIGHTS: Adults can make nuanced judgments from sound, including accurately judging the temperature of water from the sound of it being poured. Children showed protracted development of this skill over the course of middle childhood, such that 7-11-year-olds reliably succeeded while 3-6-year-olds performed at chance. Developmental changes may be due to experience (adults with greater relevant experience showed higher accuracy) and the development of multimodal integration and auditory sensitivity. Young children may not detect subtle auditory information that adults easily perceive.

Triadic conflict "primitives" can be reduced to welfare trade-off ratios.

Pietraszewski proposes four triadic "primitives" for representing social groups. We argue that, despite surface differences, these triads can all be reduced to similar underlying welfare trade-off ratios, which are a better candidate for social group primitives. Welfare trade-off ratios also have limitations, however, and we suggest there are multiple computational strategies by which people recognize and reason about social groups.

Starting small: exploring the origins of successor function knowledge.

Although most U. S. children can accurately count sets by 4 years of age, many fail to understand the structural analogy between counting and number - that adding 1 to a set corresponds to counting up 1 word in the count list. While children are theorized to establish this Structure Mapping coincident with learning how counting is used to generate sets, they initially have an item-based understanding of this relationship, and can infer that, e.g, adding 1 to "five" is "six", while failing to infer that, e.g., adding 1 to "twenty-five" is "twenty-six" despite being able to recite these numbers when counting aloud. The item-specific nature of children's successes in reasoning about the relationship between changes in cardinality and the count list raises the possibility that such a Structure Mapping emerges later in development, and that this ability does not initially depend on learning to count. We test this hypothesis in two experiments and find evidence that children can perform item-based addition operations before they become competent counters. Even after children learn to count, we find that their ability to perform addition operations remains item-based and restricted to very small numbers, rather than drawing on generalized knowledge of how the count list represents number. We discuss how these early item-based associations between number words and sets might play a role in constructing a generalized Structure Mapping between counting and quantity.

Toward inclusive theories of the evolution of musicality.

We compare and contrast the 60 commentaries by 109 authors on the pair of target articles by Mehr et al. and ourselves. The commentators largely reject Mehr et al.'s fundamental definition of music and their attempts to refute (1) our social bonding hypothesis, (2) byproduct hypotheses, and (3) sexual selection hypotheses for the evolution of musicality. Instead, the commentators generally support our more inclusive proposal that social bonding and credible signaling mechanisms complement one another in explaining cooperation within and competition between groups in a coevolutionary framework (albeit with some confusion regarding terminologies such as "byproduct" and "exaptation"). We discuss the proposed criticisms and extensions, with a focus on moving beyond adaptation/byproduct dichotomies and toward testing of cross-species, cross-cultural, and other empirical predictions.

Music as a coevolved system for social bonding.

Why do humans make music? Theories of the evolution of musicality have focused mainly on the value of music for specific adaptive contexts such as mate selection, parental care, coalition signaling, and group cohesion. Synthesizing and extending previous proposals, we argue that social bonding is an overarching function that unifies all of these theories, and that musicality enabled social bonding at larger scales than grooming and other bonding mechanisms available in ancestral primate societies. We combine cross-disciplinary evidence from archeology, anthropology, biology, musicology, psychology, and neuroscience into a unified framework that accounts for the biological and cultural evolution of music. We argue that the evolution of musicality involves gene-culture coevolution, through which proto-musical behaviors that initially arose and spread as cultural inventions had feedback effects on biological evolution because of their impact on social bonding. We emphasize the deep links between production, perception, prediction, and social reward arising from repetition, synchronization, and harmonization of rhythms and pitches, and summarize empirical evidence for these links at the levels of brain networks, physiological mechanisms, and behaviors across cultures and across species. Finally, we address potential criticisms and make testable predictions for future research, including neurobiological bases of musicality and relationships between human music, language, animal song, and other domains. The music and social bonding hypothesis provides the most comprehensive theory to date of the biological and cultural evolution of music.

Babies know bad dancing when they see it: Older but not younger infants discriminate between synchronous and asynchronous audiovisual musical displays.

Movement to music is a universal human behavior, yet little is known about how observers perceive audiovisual synchrony in complex musical displays such as a person dancing to music, particularly during infancy and childhood. In the current study, we investigated how perception of musical audiovisual synchrony develops over the first year of life. We habituated infants to a video of a person dancing to music and subsequently presented videos in which the visual track was matched (synchronous) or mismatched (asynchronous) with the audio track. In a visual-only control condition, we presented the same visual stimuli with no sound. In Experiment 1, we found that older infants (8-12months) exhibited a novelty preference for the mismatched movie when both auditory information and visual information were available and showed no preference when only visual information was available. By contrast, younger infants (5-8months) in Experiment 2 did not discriminate matching stimuli from mismatching stimuli. This suggests that the ability to perceive musical audiovisual synchrony may develop during the second half of the first year of infancy.

Is the bias for function-based explanations culturally universal? Children from China endorse teleological explanations of natural phenomena.

Young children in Western cultures tend to endorse teleological (function-based) explanations broadly across many domains, even when scientifically unwarranted. For instance, in contrast to Western adults, they explicitly endorse the idea that mountains were created for climbing, just like hats were created for warmth. Is this bias a product of culture or a product of universal aspects of human cognition? In two studies, we explored whether adults and children in Mainland China, a highly secular, non-Western culture, show a bias for teleological explanations. When explaining both object properties (Experiment 1) and origins (Experiment 2), we found evidence that they do. Whereas Chinese adults restricted teleological explanations to scientifically warranted cases, Chinese children endorsed them more broadly, extending them across different kinds of natural phenomena. This bias decreased with rising grade level across first, second, and fourth grades. Overall, these data provide evidence that children's bias for teleological explanations is not solely a product of Western Abrahamic cultures. Instead, it extends to other cultures, including the East Asian secular culture of modern-day China. This suggests that the bias for function-based explanations may be driven by universal aspects of human cognition.

The origins of dance: Characterizing the development of infants' earliest dance behavior.

Dance is a universal human behavior and a crucial component of human musicality. When and how does the motivation and tendency to move to music develop? How does this behavior change as a process of maturation and learning? We characterize infants' earliest dance behavior, leveraging parents' extensive at-home observations of their children. Parents of infants aged 0-24 months (N = 278, 82.7% White, 84.5% in the United States, 46.0% of household incomes ≥ $100,000) were surveyed regarding their child's current and earliest dance behavior (movement by the child, during music, that the parent considered dance), motor development, and their own infant-directed dance. We found that dance begins early: 90% of infants produced recognizable dance by 12.8 months, and the age of onset was not solely a function of motor development. Infants who produced dance did so often, on average almost every day. We also found that dance shows qualitative developmental change over the first 2 years, rather than remaining stable. With motor development, age, and more time dancing, infants used a greater variety of movements in dance, and began to incorporate learned, imitated gestures (80% of infants by 17.9 months). 99.8% of parents reported dancing for or with their infants, raising questions about the role of infant-directed dance. These findings provide evidence that the motivation and tendency to move to music appears extremely early and that both learning and maturation lead to qualitative change in dance behavior during the first 2 years, informing broad questions about the origins of human musicality. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Aesthetic Motivation Impacts Judgments of Others' Prosociality and Mental Life.

The ability to infer others' prosocial vs. antisocial behavioral tendencies from minimal information is core to social reasoning. Aesthetic motivation (the value or appreciation of aesthetic beauty) is linked with prosocial tendencies, raising the question of whether this factor is used in interpersonal reasoning and in the attribution of mental capacities. We propose and test a model of this reasoning, predicting that evidence of others' aesthetic motivations should impact judgments of others' prosocial (and antisocial) tendencies by signaling a heightened capacity for emotional experience. In a series of four pre-registered experiments (total N = 1440), participants saw pairs of characters (as photos/vignettes), and judged which in each pair showed more of a mental capacity of interest. Distractor items prevented participants from guessing the hypothesis. For one critical pair of characters, both characters performed the same activity (music listening, painting, cooking, exercising, being in nature, doing math), but one was motivated by the activities' aesthetic value, and the other by its functional value. Across all activities, participants robustly chose aesthetically-motivated characters as more likely to behave compassionately (Exp. 1; 3), less likely to behave selfishly/manipulatively (Exp. 1; 3), and as more emotionally sensitive, but not more intelligent (Exp. 2; 3; 4). Emotional sensitivity best predicted compassionate behavior judgements (Exp. 3). Aesthetically-motivated characters were not reliably chosen as more helpful; intelligence best predicted helpfulness judgements (Exp. 4). Evidence of aesthetic motivation conveys important social information about others, impacting fundamental interpersonal judgments about others' mental life and social behavior.

Designing and detecting lies by reasoning about other agents.

How do people detect lies from the content of messages, and design lies that go undetected? Lying requires strategic reasoning about how others think and respond. We propose a unified framework underlying lie design and detection, formalized as recursive social reasoning. Senders design lies by inferring the likelihood the receiver detects potential lies; receivers detect lies by inferring if and how the sender would lie. Under this framework, we can predict the rate and content of lies people produce, and which lies are detected. In Experiment 1, we show that people calibrate the extremeness of their lies and what lies they detect to beliefs about goals and the statistics of the world. In Experiment 2, we present stronger diagnostic evidence for the function of social reasoning in lying: people cater their lies to their audience, even when their audience's beliefs differ from their own. We conclude that recursive and rational social reasoning is a key cognitive process underlying how people communicate in adversarial settings. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Interpersonal utility and children's social inferences from shared preferences.

Similarity of behaviors or attributes is often used to infer social affiliation and prosociality. Does this reflect reasoning using a simple expectation of homophily, or more complex reasoning about shared utility? We addressed this question by examining the inferences children make from similar choices when this similarity does or does not cause competition over a zero-sum resource. Four- to six-year-olds (N = 204) saw two vignettes, each featuring three characters (a target plus two others) choosing between two types of resources. In all stories, each character expressed a preference: one 'other' chose the same resource as the target, while a second 'other' chose the different resource. In one condition there were enough resources for all the characters; in the other condition, one type of resource was limited, with only one available (inducing potential competition between the target and the similar-choice other). Children then judged which of the two 'other' characters was being nicer (prosocial judgment) and which of the two was more preferred by the target (affiliative inference). When resources were limited (vs. unlimited), children were less likely to select the similar other as being nice. Children's initial tendency to report that the target preferred the similar other was also eliminated in the limited resource scenario. These findings show that children's reasoning about similarity is not wholly based on homophily. Instead, by reasoning about shared utility - how each person values the goals of others - children engage in flexible inferences regarding whether others' similar preferences and behaviors have positive or negative social meaning.

Expectancy Effects Threaten the Inferential Validity of Synchrony-Prosociality Research.

Many studies argue that synchronized movement increases prosocial attitudes and behavior. We reviewed meta-analytic evidence that reported effects of synchrony may be driven by experimenter expectancy, leading to experimenter bias; and participant expectancy, otherwise known as placebo effects. We found that a majority of published studies do not adequately control for experimenter bias and that multiple independent replication attempts with added controls have failed to find the original effects. In a preregistered experiment, we measured participant expectancy directly, asking whether participants have a priori expectations about synchrony and prosociality that match the findings in published literature. Expectations about the effects of synchrony on prosocial attitudes directly mirrored previous experimental findings (including both positive and null effects)-despite the participants not actually engaging in synchrony. On the basis of this evidence, we propose an alternative account of the reported bottom-up effects of synchrony on prosociality: the effects of synchrony on prosociality may be explicable as the result of top-down expectations invoked by placebo and experimenter effects.

Acoustic regularities in infant-directed speech and song across cultures.

When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people from 187 countries, recruited via an English-language website, who guessed whether each vocalization was infant-directed. Their intuitions were more accurate than chance, predictable in part by common sets of acoustic features and robust to the effects of linguistic relatedness between vocalizer and listener. These findings inform hypotheses of the psychological functions and evolution of human communication.

Reasoning about 'irrational' actions: when intentional movements cannot be explained, the movements themselves are seen as the goal.

Infants and adults are thought to infer the goals of observed actions by calculating the actions' efficiency as a means to particular external effects, like reaching an object or location. However, many intentional actions lack an external effect or external goal (e.g. dance). We show that for these actions, adults infer that the agents' goal is to produce the movements themselves: Movements are seen as the intended outcome, not just a means to an end. We test what drives observers to infer such movement-based goals, hypothesizing that observers infer movement-based goals to explain actions that are clearly intentional, but are not an efficient means to any plausible external goal. In three experiments, we separately manipulate intentionality and efficiency, equating for movement trajectory, perceptual features, and external effects. We find that participants only infer movement-based goals when the actions are intentional and are not an efficient means to external goals. Thus, participants appear to infer that movements are the goal in order to explain otherwise mysterious intentional actions. These findings expand models of goal inference to account for intentional yet 'irrational' actions, and suggest a novel explanation for overimitation as emulation of movement-based goals.

Two randomized trials provide no consistent evidence for nonmusical cognitive benefits of brief preschool music enrichment.

Young children regularly engage in musical activities, but the effects of early music education on children's cognitive development are unknown. While some studies have found associations between musical training in childhood and later nonmusical cognitive outcomes, few randomized controlled trials (RCTs) have been employed to assess causal effects of music lessons on child cognition and no clear pattern of results has emerged. We conducted two RCTs with preschool children investigating the cognitive effects of a brief series of music classes, as compared to a similar but non-musical form of arts instruction (visual arts classes, Experiment 1) or to a no-treatment control (Experiment 2). Consistent with typical preschool arts enrichment programs, parents attended classes with their children, participating in a variety of developmentally appropriate arts activities. After six weeks of class, we assessed children's skills in four distinct cognitive areas in which older arts-trained students have been reported to excel: spatial-navigational reasoning, visual form analysis, numerical discrimination, and receptive vocabulary. We initially found that children from the music class showed greater spatial-navigational ability than did children from the visual arts class, while children from the visual arts class showed greater visual form analysis ability than children from the music class (Experiment 1). However, a partial replication attempt comparing music training to a no-treatment control failed to confirm these findings (Experiment 2), and the combined results of the two experiments were negative: overall, children provided with music classes performed no better than those with visual arts or no classes on any assessment. Our findings underscore the need for replication in RCTs, and suggest caution in interpreting the positive findings from past studies of cognitive effects of music instruction.

Tracking replicability as a method of post-publication open evaluation.

Recent reports have suggested that many published results are unreliable. To increase the reliability and accuracy of published papers, multiple changes have been proposed, such as changes in statistical methods. We support such reforms. However, we believe that the incentive structure of scientific publishing must change for such reforms to be successful. Under the current system, the quality of individual scientists is judged on the basis of their number of publications and citations, with journals similarly judged via numbers of citations. Neither of these measures takes into account the replicability of the published findings, as false or controversial results are often particularly widely cited. We propose tracking replications as a means of post-publication evaluation, both to help researchers identify reliable findings and to incentivize the publication of reliable results. Tracking replications requires a database linking published studies that replicate one another. As any such database is limited by the number of replication attempts published, we propose establishing an open-access journal dedicated to publishing replication attempts. Data quality of both the database and the affiliated journal would be ensured through a combination of crowd-sourcing and peer review. As reports in the database are aggregated, ultimately it will be possible to calculate replicability scores, which may be used alongside citation counts to evaluate the quality of work published in individual journals. In this paper, we lay out a detailed description of how this system could be implemented, including mechanisms for compiling the information, ensuring data quality, and incentivizing the research community to participate.

Infant-directed speech drives social preferences in 5-month-old infants.

Adults across cultures speak to infants in a specific infant-directed manner. We asked whether infants use this manner of speech (infant- or adult-directed) to guide their subsequent visual preferences for social partners. We found that 5-month-old infants encode an individuals' use of infant-directed speech and adult-directed speech, and use this information to guide their subsequent visual preferences for individuals even after the speech behavior has ended. Use of infant-directed speech may act as an effective cue for infants to select appropriate social partners, allowing infants to focus their attention on individuals who will provide optimal care and opportunity for learning. This selectivity may play a crucial role in establishing the foundations of social cognition.

Auditory-motor entrainment in vocal mimicking species: Additional ontogenetic and phylogenetic factors.

We have recently found robust evidence of motor entrainment to auditory stimuli in multiple species of non-human animal, all of which were capable of vocal mimicry. In contrast, the ability remained markedly absent in many closely related species incapable of vocal mimicry. This suggests that vocal mimicry may be a necessary precondition for entrainment. However, within the vocal mimicking species, entrainment appeared non-randomly, suggesting that other components besides vocal mimicry play a role in the capacity and tendency to entrain. Here we discuss potential additional factors involved in entrainment. New survey data show that both male and female parrots are able to entrain, and that the entrainment capacity appears throughout the lifespan. We suggest routes for future study of entrainment, including both developmental studies in species known to entrain and further work to detect entrainment in species not well represented in our dataset. These studies may shed light on additional factors necessary for entrainment in addition to vocal mimicry.

Spontaneous motor entrainment to music in multiple vocal mimicking species.

The human capacity for music consists of certain core phenomena, including the tendency to entrain, or align movement, to an external auditory pulse [1-3]. This ability, fundamental both for music production and for coordinated dance, has been repeatedly highlighted as uniquely human [4-11]. However, it has recently been hypothesized that entrainment evolved as a by-product of vocal mimicry, generating the strong prediction that only vocal mimicking animals may be able to entrain [12, 13]. Here we provide comparative data demonstrating the existence of two proficient vocal mimicking nonhuman animals (parrots) that entrain to music, spontaneously producing synchronized movements resembling human dance. We also provide an extensive comparative data set from a global video database systematically analyzed for evidence of entrainment in hundreds of species both capable and incapable of vocal mimicry. Despite the higher representation of vocal nonmimics in the database and comparable exposure of mimics and nonmimics to humans and music, only vocal mimics showed evidence of entrainment. We conclude that entrainment is not unique to humans and that the distribution of entrainment across species supports the hypothesis that entrainment evolved as a by-product of selection for vocal mimicry.