A surge of recent research on fraction representation hasprovided substantial insight into how people think aboutproportional information in written, symbolic form and invisual, non-symbolic form. However, how fractions anddecimals are verbally labeled is an often-overlooked aspect ofproportion representation. In the current study, weinvestigated how adults label fractions and decimals (Study 1)and how children in a range of grades label fractions (Study2), using a novel web-based platform for accessing studentdata from real classrooms (ASSISTments). In both studies,children and adults showed remarkable consistency in thekinds of labels they used. However, there were somedifferences in label preferences across notation and grade-level. Although the relations between fraction labeling andfraction ability remain unclear, these studies provide a firstlook at the kinds of labels that people typically use andprovide some initial hypotheses for future research intosymbolic representations of proportion.

In two experiments, we investigate how adults think aboutproportion across different symbolic and spatialrepresentations in a comparison task (Experiment 1) and atranslation task (Experiment 2). Both experiments showresponse patterns suggesting that decimal notation provides asymbolic advantage in precision when representing numericalmagnitude, whereas fraction notation does not. In addition,pie charts may show some advantages above number lineswhen translating between representations. Lastly, our findingssuggest that the translation between number lines andfractions may be particularly error-prone. We discuss whatthese performance patterns suggest in terms of how adultsrepresent proportional information across these differentformats and some potential avenues through which theseadvantages and disadvantages may arise, suggesting newquestions for future work.

Prominent theories suggest that time and number arerepresented by a common magnitude system. However,distinct patterns of temporal and numerical processingoccur in the presence of emotional stimuli, calling intoquestion theories of a common magnitude system, whilealso unveiling questions regarding the mechanismsunderlying these temporal and numerical biases. Wetested whether numerical processing, like temporalprocessing, may be impacted by increased arousal levels,yet have a higher threshold level in order to impactestimates. If so, then induced arousal may reverse thetypical pattern of numerical underestimation in thepresence of emotions. Adults (N = 85) participated ineither a stress-induction or a control version of the task.Then, participants completed a numerical bisection task inthe presence and absence of emotional content. Increasingarousal had no impact on numerical processing, except inthe presence of happy faces, providing further evidencefor distinct processing mechanisms.

Young children share fairly and expect others to do the same.Yet little is known about the underlying cognitivemechanisms that support fairness. Across two experiments,we investigated whether children’s numerical competenciesare linked with their sharing behavior. Preschoolers (aged2.5-5.5) participated in either third-party (Experiment 1) orfirst-party (Experiment 2) resource allocation tasks.Children’s numerical competence was then assessed using theGive-N-Task (Sarnecka & Carey, 2008; Wynn, 1990).Numerical competence – specifically knowledge of thecardinal principle explained age-related changes in fairsharing in both the third- and first-party contexts. Theseresults suggest that an understanding of the cardinal principleserves as an important mechanism for fair sharing behavior.

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure.