Manos Tsakiris

Remote photoplethysmography (rPPG) enables non-invasive heart rate (HR) measurement via video, offering a promising tool for remote physiological monitoring. In a previous study, we validated an adapted rPPG algorithm developed by van der Kooij and Naber (Behav Res Methods 51(5):2106–2119, 2019), collecting video via an online platform using a common web browser and comparing results to phone-based HR measurements. In the present study, we extend this methodological pipeline by validating the same refined algorithm and online video collection pipeline against electrocardiogram (ECG) ground-truth measurements. While previous studies have typically relied on online data collection without ECG reference standards or laboratory-based protocols lacking online implementation, our study bridges this gap by directly comparing video data collected through a standard web browser using the Gorilla Experiment Builder platform with simultaneous ECG recordings. We also evaluated the optimal conditions for rPPG accuracy in terms of video duration and distance from the webcam. We recorded 180 videos across five durations (10 s, 25 s, 35 s, 45 s, and 100 s) and two distances (close = 35 cm, far = 50 cm). Results showed excellent agreement between rPPG- and ECG-derived HR, with an intraclass correlation coefficient (ICC) of 0.96 and 95% of measurements within Bland–Altman limits of agreement. Longer video durations significantly reduced error and variability, while recording distance had no significant effect. Validation of this rPPG pipeline against ECG ground truth establishes the reliability of web-based rPPG measurements, providing a foundation for large-scale online data collection with fidelity comparable to controlled laboratory assessments.

Political emotions are widely acknowledged as key drivers of political participation and polarization. Yet while it is well established that political emotions matter, far less is known about how they are felt and represented in the body. Across a preregistered, nationally representative study (N = 992), we introduce an embodied approach to political emotion using the validated emBODY-tool, which allows participants to map where in the body they experience sensations when feeling canonical emotions (e.g., anger) and their political counterparts (e.g., “political anger”). Specifically, we address three questions: 1) how political emotions are embodied and differ from their nonpolitical counterparts, 2) whether political dispositions influence how these political emotions are embodied, and 3) how their embodied experience interacts with political dispositions in explaining political attitudes and behavior. Pixelwise bodily sensation maps and aggregated “embodied impact” metrics show that political anger, anxiety, depression, disgust, and hope do not merely mirror their canonical forms, but take on distinct bodily patterns. Political ideology, but not political sophistication, modulates these bodily experiences, with Democrat-leaning participants reporting more intense sensations for negative political emotions, suggesting the presence of “ideological bodies.” Crucially, political participation is not explained by how intensely people report feeling emotions, but is instead closely linked to how strongly these emotions are embodied in the body. Together, our findings underscore the body’s central role in democratic engagement by showing how political contexts shape embodied emotional experience and how these embodied experiences shape politics and democracy.

People often favour information aligned with their ideological motives. Can our tendency for directional motivated reasoning be overcome with cognitive control? It remains contested whether cognitive control processes, such as cognitive reflection and inhibitory control, are linked to a greater tendency to engage in politically motivated reasoning, as proposed by the “motivated reflection” hypothesis, or can help people overcome it, as suggested by cognitive science research. In this pre-registered study (N = 504 UK participants rating n = 4963 news messages), we first provide evidence for motivated reasoning on multiple political and non-political topics. We then investigated the associations of the two cognitive control variables cognitive reflection and inhibitory control with motivated reasoning. We find that associations between cognitive control processes and motivated reasoning are likely small. On political topics specifically, we find that a negative association with cognitive reflection is more likely than a positive association. This finding is contrary to predictions from the popular motivated reflection hypothesis. Results for inhibitory control are inconclusive. We discuss how these findings relate to interdisciplinary literature from cognitive and political psychology.