52% Yes, a signiicant crisis 3% No, there is no crisis 7% Don't know 38% Yes, a slight crisis 38% Yes, a slight crisis 1,576 RESEARCHERS SURVEYED M ore than 70% of researchers have tried and failed to reproduce another scientist's experiments, and more than half have failed to reproduce their own experiments. Those are some of the telling figures that emerged from Nature's survey of 1,576 researchers who took a brief online questionnaire on reproducibility in research. The data reveal sometimes-contradictory attitudes towards reproduc-ibility. Although 52% of those surveyed agree that there is a significant 'crisis' of reproducibility, less than 31% think that failure to reproduce published results means that the result is probably wrong, and most say that they still trust the published literature. Data on how much of the scientific literature is reproducible are rare and generally bleak. The best-known analyses, from psychology 1 and cancer biology 2 , found rates of around 40% and 10%, respectively. Our survey respondents were more optimistic: 73% said that they think that at least half of the papers in their field can be trusted, with physicists and chemists generally showing the most confidence. The results capture a confusing snapshot of attitudes around these issues, says Arturo Casadevall, a microbiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. "At the current time there is no consensus on what reproducibility is or should be. " But just recognizing that is a step forward, he says. "The next step may be identifying what is the problem and to get a consensus. "

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.

No abstract

One benefit of working in groups is that group members can learn from each other how to perform the task, a phenomenon called group-to-individual transfer (G-I transfer). In the context of quantitative judgments, G-I transfer means that group members improve their individual accuracy as a consequence of exchanging task-relevant information. This improved individual accuracy allows groups to outperform the average of a comparable number of individuals, that is, G-I transfer leads to synergy. While there is mounting evidence that group members benefit from G-I transfer in quantitative judgment tasks, we still know rather little about what exactly group members learn from each other during this transfer. Here, we build on the distinction between metric knowledge (knowing what constitutes a plausible range of values) and mapping knowledge (knowing the relative magnitude of the targets) to gain further insights into the nature of G-I transfer. Whereas previous research found evidence that G-I transfer improves group members’ metric knowledge, there is, so far, no evidence that group discussion also improves mapping knowledge. Using a multicue judgment task, we tested whether group members would benefit from G-I-transfer and, if so, whether this G-I transfer would manifest in the form of improved mapping knowledge. The results of two experiments suggest that this is the case. Participants who worked in real interacting groups outperformed participants who worked individually, and this increase in accuracy was accompanied not only by improved metric but also by increased mapping knowledge.

Test-retest reliability — establishing that measurements remain consistent across multiple testing sessions — is critical to measuring, understanding, and predicting individual differences in infant language development. However, previous attempts to establish measurement reliability in infant speech perception tasks are limited, and reliability of frequently-used infant measures is largely unknown. The current study investigated the test-retest reliability of infants’ preference for infant-directed speech (hereafter, IDS) over adult-directed speech (hereafter, ADS) in a large sample (N=158) in the context of the ManyBabies1 collaborative research project (hereafter, MB1; Frank et al., 2017; ManyBabies Consortium, 2020). Labs of the original MB1 study were asked to bring in participating infants for a second appointment retesting infants on their IDS preference. This approach allows us to estimate test-retest reliability across three different methods used to investigate preferential listening in infancy: the head-turn preference procedure, central fixation, and eye-tracking. Overall, we find no consistent evidence of test-retest reliability in measures of infants’ speech preference (overall r = .09, 95% CI [-.06,.25]). While increasing the number of trials that infants needed to contribute for inclusion in the analysis revealed a numeric growth in test-retest reliability, it also considerably reduced the study’s effective sample size. Therefore, future research on infant development should take into account that not all experimental measures may be appropriate for assessing individual differences between infants.