Max Planck Institute for Human Development

In neuroimaging research, tracking individuals over time is key to understanding the interplay between brain changes and genetic, environmental, or cognitive factors across the lifespan. Yet, the extent to which we can estimate the individual trajectories of brain change over time with precision remains uncertain. In this study, we estimated the reliability of structural brain change in cognitively healthy adults from multiple samples and assessed the influence of follow-up time and number of observations. Estimates of cross-sectional measurement error and brain change variance were obtained using the longitudinal FreeSurfer processing stream. Our findings showed, on average, modest longitudinal reliability with 2 years of follow-up. Increasing the follow-up time was associated with a substantial increase in longitudinal reliability, while the impact of increasing the number of observations was comparatively minor. On average, 2-year follow-up studies require ≈2.7 and ≈4.0 times more individuals than designs with follow-ups of 4 and 6 years to achieve comparable statistical power. Subcortical volume exhibited higher longitudinal reliability than cortical area, thickness, and volume. The reliability estimates were comparable with those estimated from empirical data. The reliability estimates were affected by both the cohort’s age where younger adults had lower reliability of change and the preprocessing pipeline where the FreeSurfer’s longitudinal stream was notably superior than the cross-sectional stream. Suboptimal reliability inflated sample size requirements and compromised the ability to distinguish individual trajectories of brain aging. This study underscores the importance of long-term follow-ups and the need to consider reliability in longitudinal neuroimaging research.

The COVID-19 pandemic provided a stark reminder that societies will struggle to address global challenges unless they are able to change behaviour at scale. The widely adopted ‘nudge’ approach epitomizes an individualistic, deficit model of human cognition and motivation that leverages or overcomes people’s weaknesses and biases to get them to do things they would otherwise not. By contrast, we argue that tackling the challenges facing humanity requires a collective, capacity-building approach – one that boosts the competences, opportunities, and motivations of individuals to act together.

This paper examines the transformative potential of AI embedded with counterfactual world simulation models (CWSMs). A CWSM uses multimodal evidence, such as the CCTV footage of a road accident, to build a high-fidelity 3D reconstruction of what happened. It can answer causal questions, such as whether the accident happened because the driver was speeding, by simulating what would have happened in relevant counterfactual situations. We sketch a normative and ethical framework that guides and constrains the simulation of counterfactuals. We address the challenge of ensuring fidelity in reconstructions while simultaneously preventing stereotype perpetuation during counterfactual simulations. We anticipate different modes of how users will interact with AI-powered CWSMs and discuss how their outputs may be presented. Finally, we address the prospective applications of CWSMs in the legal domain, recognizing both their potential to revolutionize legal proceedings as well as the ethical concerns they engender. Sketching a new genre of AI, this paper seeks to illuminate the path forward for responsible and effective use of CWSMs.

The remarkable ecological success of humans is often attributed to our ability to develop complex cultural artefacts that enable us to cope with environmental challenges. The evolution of complex culture (cumulative cultural evolution) is usually modelled as a collective process in which individuals invent new artefacts (innovation) and copy information from others (social learning). This classic picture overlooks the growing role of intelligent algorithms in the digital age (e.g. search engines, recommender systems and large language models) in mediating information between humans, with potential consequences for cumulative cultural evolution. Building on a previous model, we investigate the combined effects of network-based social learning and a simplistic version of algorithmic mediation on cultural accumulation. We find that algorithmic mediation significantly impacts cultural accumulation and that this impact grows as social networks become less densely connected. Cultural accumulation is most effective when social learning and algorithmic mediation are combined, and the optimal ratio depends on the network’s density. This work is an initial step towards formalizing the impact of intelligent algorithms on cumulative cultural evolution within an established framework. Models like ours provide insights into mechanisms of human–machine interaction in cultural contexts, guiding hypotheses for future experimental testing.

Marginalization due to structural racism may confer an increased risk for aging-related diseases – in part – via effects on people’s mental health. Here we leverage a prospective birth cohort study to examine whether the emergence of racial disparities in mental health and DNA-methylation measures of biological aging (i.e., DunedinPACE, GrimAge Acceleration, PhenoAge Acceleration) are linked across childhood and adolescence. We further consider to what extent racial disparities are statistically accounted for by perinatal and postnatal factors in preregistered analyses of 4898 participants from the Future of Families & Child Wellbeing Study, of which 2039 had repeated saliva DNA methylation at ages 9 and 15 years. We find that racially marginalized children had higher levels of externalizing and internalizing behaviors and diverging longitudinal internalizing slopes. Black compared to White identifying children, children living in more racially segregated neighborhoods, and racially marginalized children more affected by colorism tended to have higher age-9 levels of biological aging and more biological age acceleration over adolescence. Notably, longitudinal increases in internalizing and externalizing behavior were correlated with increases in biological aging. While racial and ethnic disparities in mental health were largely statistically accounted for by socioeconomic variables, differences in biological aging were often still visible after including potential mediating variables. These findings underscore the urgency for future research to consider biological aging processes from early life and collect more comprehensive measures of structural racism in developmental cohorts. Programs dedicated to advancing racial health equity must address the psychological and physical effects of structural racism on children and adolescents.

Background To make reasonable future medical decisions, medical students need to be sufficiently educated to interpret diagnostic tests. Natural frequencies are considered the gold standard for understanding single diagnostic test results. However, they may be less suitable in situations involving sequential diagnostic testing. We test whether odds and likelihood ratios (odds/LR) may serve as a viable alternative in these situations. Methods In our preregistered randomized-controlled crossover trial, we recruited 167 medical students and 162 psychology students. The proportion of correctly calculated positive predictive values of a single (PPV) and two sequential diagnostic tests (sPPV) was the primary, the subjective comprehensibility of the information the secondary outcome. Results The proportion of correct PPVs was significantly higher in the natural frequency (36.2%) compared to the odds/LR format (21.6%), OR 2.41. Conversely, the proportion of correct sPPVs was significantly higher in the odds/LR (10.6%) compared to the natural frequency format (4.9%), OR 2.73. Participants indicated a higher subjective comprehension of test statistics phrased as natural frequencies (Mdn = 19) than as odds/LR (Mdn = -15), r = .61. Conclusion Teaching Odds/LR next to natural frequencies potentially improves medical students’ understanding of PPV and may enhance their ability to make future diagnostic decisions. Trial registration https://doi.org/10.17605/OSF.IO/F3297.

Anorexia nervosa (AN) is a severe eating disorder, marked by persistent changes in behaviour, cognition and neural activity that result in insufficient body weight. Recently, there has been a growing interest in using computational approaches to understand the cognitive mechanisms that underlie AN symptoms, such as persistent weight loss behaviours, rigid rules around food and preoccupation with body size. Our aim was to systematically review progress in this emerging field. Based on articles selected using systematic and reproducible criteria, we identified five current themes in the computational study of AN: 1) reinforcement learning; 2) value-based decision-making; 3) goal-directed and habitual control over behaviour; 4) cognitive flexibility; and 5) theory-based accounts. In addition to describing and appraising the insights from each of these areas, we highlight methodological considerations for the field and outline promising future directions to establish the clinical relevance of (neuro)computational changes in AN.

Information about the consequences of our consumption choices can be unwelcome, and people sometimes avoid it. Thus, when people possess information that is inconvenient for another person, they may face a dilemma about whether to inform them. We introduce a simple and portable experimental game to analyze the transmission of inconvenient information. In this game, a Sender can, at a small cost, inform a Receiver about a negative externality associated with a tempting and profitable action for the Receiver. The results from our online experiment (N = 1,512) show that Senders transmit more information when negative externalities are larger and that Senders’ decisions are largely driven by their own preferences towards the charity and their own use of information. We do not find evidence that Senders take the Receiver’s preferences into account, as they largely ignore explicit requests for information, or ignorance, even if Receivers have the option to punish the Sender.

DNA‐methylation profile scores (MPSs) index biology relevant for lifelong physical and cognitive health, but information on their longitudinal stability in childhood is lacking. Using two waves of data collected from 2014 to 2022 ( M lag between waves = 2.41 years) from N = 407 participants ( M age = 12.05 years, 51% female, 60% White), test–retest correlations were estimated for four salivary MPSs related to aging (PhenoAgeAccel, GrimAgeAccel, DunedinPACE), and cognitive function (Epigenetic‐ g ). MPSs varied in longitudinal stability (test–retest r s = 0.38 to 0.76). MPSs did not differ in children exposed to the COVID‐19 pandemic, but race‐ethnic and sex differences were apparent. Further research is necessary to understand which environmental perturbations impact DNA‐methylation trajectories and when children are most sensitive to those impacts.

This chapter meticulously examines the transformative journey of heroines from East Asian folklore, seamlessly connecting traditional narratives with the complexities of contemporary society. Focused on the formidable figures of Tomoe Gozen from Japan, Mulan from China, and Princess Bari from Korea, a thorough comparative analysis unravels their intricate representation, evolution, and enduring significance. These three iconic figures transcend the boundaries of myth and tap into real-life contexts through their embodying roles as fearless warriors and symbols of life and death. Their collective impact sparks ongoing dialogues on the interactive interplay between identity, empowerment, and cultural resilience. Beyond the constraints of myth, the narratives of Tomoe Gozen, Mulan, and Princess Bari traverse temporal dimensions by addressing present-day concerns and serving as wellsprings of inspiration. These stories, intricately interwoven into both popular culture and real-life scenarios, contribute to a shared legacy that transcends cultural, geographical, and temporal distances. The ongoing transformation of these heroines, from their mythical origins to the contemporary, invites sustained inquiry. Their open-ended narratives beckon reinterpretation and foster engaging engagement with evolving discourses. Tomoe Gozen, Mulan, and Princess Bari emerge as timeless exemplars of heroism. They resonate through time and molding enduring narratives that transcend their mythical beginnings. This exploration highlights the enduring power of these iconic figures in shaping the discourse on heroism across cultures and generations.

Water is a key scarce resource. Therefore, most hotels place written messages in their rooms to promote guests’ water-saving behaviors. Existing research has focused on how nudges prompt towel reuse, reducing water consumption indirectly. We examine the impact of a boost—that fosters people’s competences—on direct water consumption in the shower, tap, and toilet. We conducted two field studies in Mallorca, Spain, in 2022 and 2023, at 14 hotel rooms equipped with digital water meters. In treatment rooms, guests were exposed to a leaflet informing them about water scarcity in Mallorca and of ways to save water in the hotel room. In the control condition, rooms had no leaflets. The results show that the boost had no impact on guests’ water savings—but on towel reuse. Our findings, with important implications for hotel management and policy making, show some limits of boosts for direct water conservation and reveal a possible form of greenwashing.

Until recently, most concepts and theories used in social sciences and the humanities were developed in the West. They were both provincial, as they were based on Western experience and designed to interpret these local experiences, and presumed universal. If they did not fit developments in the Global South, this was due not to the inadequacy of the concept but to a “history of lack.” Dilip M. Menon's edited volume Changing Theory: Concepts from the Global South can be situated within the broader movement to not only challenge these concepts and theories but also offer alternatives developed from the Global South. This review article lays out the larger intellectual framework of the volume. The history of concepts offers the possibility to distinguish more precisely between concepts used by the historical actors (hardly anyone challenges the need to base research on their careful investigation) and the analytical concepts. Especially in a global context, using analytical concepts from one of the languages of the Global South raises many questions that need to be addressed; the question of which language academics are to communicate with in the future is not the least important. Paracoloniality, the notion that there are areas of continuity beyond the “tired triad” of the precolonial, colonial, and postcolonial, in turn, needs to be brought into conversation with the central assumption of decoloniality, which argues for an epistemic rupture between the precolonial and the colonial.

Exposure and response prevention therapy in virtual reality (VERP) for patients with obsessive-compulsive disorder (OCD) has been investigated primarily for its effectiveness. This study evaluated an important research gap, the negative and positive side effects of VERP and its safety. Eighty outpatients with contamination- or checking-related OCD were randomized to two conditions: VERP (six weekly sessions) or care as usual (CAU). Assessments were conducted at baseline (t0), 6 weeks after t0 (t1), and 3 months after t1 (t2). General side effects (Negative and Positive Side Effects Questionnaire; NPSE) and those specific to virtual reality (VERP-Specific Side Effects Questionnaire; VEQ) were assessed at t1. Cybersickness (Simulator Sickness Questionnaire; SSQ) was assessed before and after each session. The safety evaluation involved assessing the worsening of OC-symptoms (Reliable Change Index of the Yale-Brown Obsessive-Compulsive Scale; Y‑BOCS) from t0 to t1 and serious adverse events during the intervention. Results indicated no significant clinical symptom deterioration in the VERP group and no adverse events. In total, 47% of participants in both groups experienced at least one side effect, with significantly fewer reported in the VERP than in the CAU group (p < 0.001). Concerning VERP-specific side effects, at least one side effect was found in 55% of the patients. The SSQ total score did not significantly change from before to after the VERP sessions (p = 0.098, Cohen's d = 0.297). In conclusion, VERP was safe and demonstrated few side effects, highlighting its potential as a well-tolerated and safe intervention for patients with OCD.

Purpose Ultrahigh‐field (UHF; ≥7 T) MRI is challenging due to spatially heterogeneous B1⁺ profiles. This longitudinal study evaluates the reproducibility of three parallel‐transmission excitation strategies to enable UHF cardiac MRI: vendor‐supplied radiofrequency (RF) shim, subject‐tailored kT‐points pulses (TPs), and universal kT‐points pulses (UPs). Methods Six healthy subjects underwent 7 T MRI scans performed by different MR operators using a 32‐element parallel‐transmission body array at four time points over 3 years. A single UP was computed and applied to all subjects. TPs were computed individually for each scan and organized into four configurations. Each configuration was applied to all scans from each subject to analyze intrasubject variability. Reproducibility was assessed by comparing the coefficient of variation (CV) of simulated flip angles (FAs) within the heart volume across scan sessions. Results TPs designed for a specific scan session yielded lower CVs (2‐fold reduction) than UP. Applying TPs to other scan sessions of the same subject, however, resulted in approximately 40% higher CVs and lower FA uniformity compared with the UP. On average, the UP consistently achieved the most reproducible results across inter‐year, inter‐day, and same‐operator studies, with CVs of approximately 12%. Conclusion Although TPs showed advantages when tailored for a specific target volume, they struggled with long‐term consistency and required lengthy calibration. The precomputed UP kT‐points pulses proved to be the most consistent across all scans acquired in the 3 years by different operators, minimizing CV‐data dispersion and maintaining FA uniformity.

Nature exposure has numerous health benefits and might reduce self-reported acute pain. Given the multi-faceted and subjective quality of pain and methodological limitations of prior research, it is unclear whether the evidence indicates genuine analgesic effects or results from domain-general effects and subjective reporting biases. This preregistered neuroimaging study investigates how nature modulates nociception-related and domain-general brain responses to acute pain. Healthy participants (N = 49) receiving electrical shocks report lower pain when exposed to virtual nature compared to matched urban or indoor control settings. Multi-voxel signatures of pain-related brain activation patterns demonstrate that this subjective analgesic effect is associated with reductions in nociception-related rather than domain-general cognitive-emotional neural pain processing. Preregistered region-of-interest analyses corroborate these results, highlighting reduced activation of areas connected to somatosensory aspects of pain processing (thalamus, secondary somatosensory cortex, and posterior insula). These findings demonstrate that virtual nature exposure enables genuine analgesic effects through changes in nociceptive and somatosensory processing, advancing our understanding of how nature may be used to complement non-pharmacological pain treatment. That this analgesic effect can be achieved with easy-to-administer virtual nature exposure has important practical implications and opens novel avenues for research on the precise mechanisms by which nature impacts our mind and brain.

Pattern separation, or distinguishing similar experiences from one another, and pattern completion, in which components of an experience prompt retrieval or forgetting of an event pattern as a unit, are essential components of episodic memory. However, these two components are sometimes described as opposite ends of a continuum and sometimes described as independent processes. Here, we examined the relations between the two processes for the same events in children between 4 and 7 y. Mnemonic discrimination (the behavioral signature of pattern separation) improved with age; holistic recollection (the behavioral signature of pattern completion) did not change in this age range. Crucially, the two behaviors were unrelated, controlling for the effect of age, and even when examining their relations at the fine-grained level of memory for individual events.