Emerging complexity in children's conceptualization of the wealthy and the poor

Past work suggests that children have an overly rosy view of rich people that stays consistent across childhood. However, adults do not show explicit pro-rich biases and even hold negative stereotypes against the rich (e.g., thinking that rich people are cold and greedy). When does this developmental shift occur, and when do children develop more complex and differentiated understandings of the wealthy and the poor? The current work documents the developmental trajectory of 4- to 12-year-old primarily American middle-class children’s conceptualizations of the wealthy and the poor (total N = 164). We find: 1) age-related decreases in pro-rich preferences and stereotypes relative to the poor; 2) domain-sensitive stereotypes across prosociality, talent, and effort; 3) resource-specific behavioral expectations such that with age children increasingly expect the wealthy to contribute more material resources but not more time than the poor; 4) an increasing recognition of the unfairness of the wealth gap between the wealthy and the poor; and 5) a developing understanding of the link between wealth and power. In sum, this work illuminates the emergence of more complex understandings of wealth, poverty, and inequality.

Spatial and featural cue weighting in children’s developing object representations

To accurately represent an object, it must be individuated from the surrounding objects and then classified with the appropriate category or identity. To this end, adults flexibly weight different visual cues when perceiving objects. However, less is known about whether, and how, the weighting of visual object information changes over development. The current study examined how children use different types of information— spatial (e.g., left/right location) and featural (e.g., color)—in different object tasks. In Experiment 1, we tested whether infants and preschoolers extract both the spatial and featural properties of objects, and, importantly, how these cues are weighted when pitted against each other. We found that infants relied primarily on spatial cues and neglected featural cues. By contrast, preschoolers showed the opposite pattern of weighting, placing greater weight on featural information. In Experiment 2, we tested the hypothesis that the developmental shift from spatial to featural weighting reflects a shift from a priority on object individuation (how many objects) in infancy to object classification (what are the objects) at preschool age. Here, we found that preschoolers weighted spatial information more than features when the task required individuating objects without identifying them, consistent with a specific role for spatial information in object individuation. We discuss the relevance of spatial-featural weighting in relation to developmental changes in children’s object representations.

Developmental shift to mitochondrial respiration for energetic support of sustained transmission during maturation at the calyx of Held

A considerable amount of energy is expended following presynaptic activity to regenerate electrical polarization and maintain efficient release and recycling of neurotransmitter. Mitochondria are the major suppliers of neuronal energy, generating ATP via oxidative phosphorylation. However, the specific utilization of energy from cytosolic glycolysis rather than mitochondrial respiration at the presynaptic terminal during synaptic activity remains unclear and controversial. We use a synapse specialized for high frequency transmission in mice, the calyx of Held, to test the sources of energy utilized to maintain energy during short activity bursts (<1 sec) and sustained neurotransmission (30-150 sec). We dissect the role of presynaptic glycolysis versus mitochondrial respiration by acutely and selectively blocking these ATP-generating pathways in a synaptic preparation where mitochondria and synaptic vesicles are prolific, under near-physiological conditions. Surprisingly, if either glycolysis or mitochondrial ATP production is intact, transmission during repetitive short bursts of activity is not affected. In slices from young animals prior to the onset of hearing, where the synapse is not yet fully specialized, both glycolytic and mitochondrial ATP production are required to support sustained, high frequency neurotransmission. In mature synapses, sustained transmission relies exclusively on mitochondrial ATP production supported by bath lactate, but not glycolysis. At both ages, we observe that action potential propagation begins to fail prior to defects in synaptic vesicle recycling. Our data describe a specific metabolic profile to support high-frequency information transmission at the mature calyx of Held, shifting during postnatal synaptic maturation from glycolysis to rely on monocarboxylates as a fuel source.

No intrinsic number bias: evaluating the role of perceptual discriminability in magnitude categorization

Accumulating evidence suggests that there is a spontaneous preference for numerical, compared to non-numerical (e.g., cumulative surface area), information. However, given a paucity of research on the perception of non-numerical magnitudes, it is unclear whether this preference reflects a specific bias towards numerosity, or a general bias towards the most perceptually discriminable dimension. Here, we found that when the number and area of visual dot displays were matched in mathematical ratio, number was more perceptually discriminable than area in both adults and children. Moreover, both adults and children preferentially categorized these ratio-matched stimuli based on number, consistent with previous work. However, when number and area were matched in perceptual discriminability, a different pattern of results emerged. In particular, children preferentially categorized stimuli based on area, suggesting that children’s previously observed number bias was due to a mismatch in the perceptual discriminability of number and area, not an intrinsic salience of number. Interestingly, adults continued to categorize the displays on the basis of number. Altogether, these findings suggest a dominant role of area during childhood, refuting the claim that number is inherently and uniquely salient. Yet they also reveal an increased salience of number that emerges over development. Potential explanations for this developmental shift are discussed.

The potential for effective reasoning guides children’s preference for small group discussion over crowdsourcing

Communication between social learners can make a group collectively “wiser” than any individual, but conformist tendencies can also distort collective judgment. We asked whether intuitions about when communication is likely to improve or distort collective judgment could allow social learners take advantage of the benefits of communication while minimizing the risks. In three experiments (n=360), 7- to 10-year old children and adults decided whether to refer a question to a small group for discussion or “crowdsource” independent judgments from individual advisors. For problems which could be conclusively solved through “demonstrable” analytic or physical reasoning, all ages preferred to consult the group, even compared to a crowd ten times as large — consistent with past research suggesting that groups regularly outperform even their best members for reasoning problems. In contrast, we observed a consistent developmental shift towards crowdsourcing independent judgments when reasoning by itself was insufficient to conclusively answer a question. Results suggest sophisticated intuitions about the nature of social influence and collective intelligence may guide our social learning strategies from early in development.

Young children’s trust in the false testimony of ingroup versus outgroup speakers.

The present research explores whether young children display different levels of trust in the testimony of speakers from their own social group (ingroups) versus another social group (outgroups). Three- and 4-year-old children watched through a window as an adult hid a toy in one of three containers. The adult then told the child that she had put the toy in a container different from the one where it was actually hidden (i.e., false testimony). At the end the child was asked to retrieve the toy. The adult was either a Caucasian, native English speaker ingroup) or an Asian English speaker with a noticeable foreign accent (outgroup). Four-year-old children were credulous to the false testimony of the ingroup speaker, despite their firsthand observations, but were skeptical and relied on their own observations when the false testimony was provided by the outgroup speaker. In contrast, 3-year-old children remained credulous to the false testimony of both speakers. These findings were discussed in relation to children’s early preferences for ingroup members and the developmental shift in skepticism displayed by 4-year-old, but not 3-year-old children. This research will make a unique contribution to our understanding of how young children selectively learn from other people and why they remain credulous to some speakers, but not to others.

Young children’s trust in the false testimony of ingroup versus outgroup speakers.

The present research explores whether young children display different levels of trust in the testimony of speakers from their own social group (ingroups) versus another social group (outgroups). Three- and 4-year-old children watched through a window as an adult hid a toy in one of three containers. The adult then told the child that she had put the toy in a container different from the one where it was actually hidden (i.e., false testimony). At the end the child was asked to retrieve the toy. The adult was either a Caucasian, native English speaker ingroup) or an Asian English speaker with a noticeable foreign accent (outgroup). Four-year-old children were credulous to the false testimony of the ingroup speaker, despite their firsthand observations, but were skeptical and relied on their own observations when the false testimony was provided by the outgroup speaker. In contrast, 3-year-old children remained credulous to the false testimony of both speakers. These findings were discussed in relation to children’s early preferences for ingroup members and the developmental shift in skepticism displayed by 4-year-old, but not 3-year-old children. This research will make a unique contribution to our understanding of how young children selectively learn from other people and why they remain credulous to some speakers, but not to others.

Developmental depression-facilitation shift controls excitation-inhibition balance

Changes in the short-term dynamics of excitatory synapses over development have been observed throughout cortex, but their purpose and consequences remain unclear. Here, we propose that developmental changes in synaptic dynamics buffer the effect of slow inhibitory long-term plasticity, allowing for continuously stable neural activity. Using computational modelling we demonstrate that early in development excitatory short-term depression quickly stabilises neural activity, even in the face of strong, unbalanced excitation. We introduce a model of the commonly observed developmental shift from depression to facilitation and show that neural activity remains stable throughout development, while inhibitory synaptic plasticity slowly balances excitation, consistent with experimental observations. Our model predicts changes in the input responses from phasic to phasic-and-tonic and more precise spike timings. We also observe a gradual emergence of synaptic working memory mediated by short-term facilitation. We conclude that the developmental depression-to-facilitation shift may control excitation-inhibition balance throughout development with important functional consequences.

The challenge of relational referents in early word extensions: Evidence from noun-noun compounds

Young children struggle more with mapping novel words onto relational referents (e.g., verbs) compared to non-relational referents (e.g., nouns). We present further evidence for this notion by investigating children's extensions of noun-noun compounds, which map onto combinations of non-relational referents, i.e., objects (e.g., baby and bottle for baby bottle), and relations (e.g., a bottle FOR babies). We tested two- to five-year-olds’ and adults’ generalisations of novel compounds composed of novel (e.g., kig donka) or familiar (e.g., star hat) nouns that were combined by one of two relations (e.g., donka that has a kig attached (=attachment relation) versus donka that stores a kig (=function relation)). Participants chose between a relational (shared relation) and a non-relational (same colour) match. Results showed a developmental shift from encoding non-relational aspects (colour) towards relations of compound referents, supporting the challenge of relational word referents. Also, attachment relations were more frequently encoded than function relations.