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Creators/Authors contains: "Ko, Michael"

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  1. Candido, Silvio_Eduardo Alvarez (Ed.)
    As social media becomes a key channel for news consumption and sharing, proliferating partisan and mainstream news sources must increasingly compete for users’ attention. While affective qualities of news content may promote engagement, it is not clear whether news source bias influences affective content production or virality, or whether any differences have changed over time. We analyzed the sentiment of ~30 million posts (ontwitter.com) from 182 U.S. news sources that ranged from extreme left to right bias over the course of a decade (2011–2020). Biased news sources (on both left and right) produced more high arousal negative affective content than balanced sources. High arousal negative content also increased reposting for biased versus balanced sources. The combination of increased prevalence and virality for high arousal negative affective content was not evident for other types of affective content. Over a decade, the virality of high arousal negative affective content also increased, particularly in balanced news sources, and in posts about politics. Together, these findings reveal that high arousal negative affective content may promote the spread of news from biased sources, and conversely imply that sentiment analysis tools might help social media users to counteract these trends. 
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  2. When playing single-shot behavioral economic games like the Trust and Dictator Games, European Americans and East Asians invested in and gave more to targets whose smiles matched their culture’s idealaffect (the affective states they value; Blevins et al., 2024; Park et al., 2017), suggesting that smiles signal something about targets’ traits. But what happens when participants are given direct information about targets’ traits; do targets’ smiles still matter for resource sharing? To answer this question, we conducted four studies from 2019 to 2022 in which 429 European Americans and 413 Taiwanese played single-shot Trust Games with open, toothy “excited” smiling targets, closed “calm” smiling targets, and nonsmiling “neutral” targets that varied in their reputations for being trustworthy, competent, and emotionally stable. When targets’ reputations were ambiguous (e.g., “50% of previous players said they were trustworthy”), European American and Taiwanese participants invested more in targets whose smiles matched their culture’s ideal affect. However, when targets’ reputations were clearly good (e.g., “80% of previous players said they were trustworthy”) or bad (e.g., “20% of previous players said they were trustworthy”), European Americans invested equally in all targets, suggesting that reputational information about targets’ traits mattered more than targets’ smiles. The pattern for Taiwanese, however, differed: Taiwanese invested equally in calm and neutral targets when targets’ reputations were clear, but regardless of their reputations, Taiwanese invested in excited targets the least. We discuss the implications of these findings for understanding cultural differences in the meaning of an excited smile in the context of resource sharing. 
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    Free, publicly-accessible full text available December 30, 2025
  3. Abstract European Americans view high-intensity, open-mouthed ‘excited’ smiles more positively than Chinese because they value excitement and other high arousal positive states more. This difference is supported by reward-related neural activity, with European Americans showing greater Nucleus Accumbens (NAcc) activity to excited (vs calm) smiles than Chinese. But do these cultural differences generalize to all rewards, and are they related to real-world social behavior? European American (N = 26) and Chinese (N = 27) participants completed social and monetary incentive delay tasks that distinguished between the anticipation and receipt (outcome) of social and monetary rewards while undergoing Functional Magnetic Resonance Imaging (FMRI). The groups did not differ in NAcc activity when anticipating social or monetary rewards. However, as predicted, European Americans showed greater NAcc activity than Chinese when viewing excited smiles during outcome (the receipt of social reward). No cultural differences emerged when participants received monetary outcomes. Individuals who showed increased NAcc activity to excited smiles during outcome had friends with more intense smiles on social media. These findings suggest that culture plays a specific role in modulating reward-related neural responses to excited smiles during outcome, which are associated with real-world relationships. 
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  4. null (Ed.)
  5. This paper describes the first implementation of an array of two-dimensional (2D) layered conductive metal–organic frameworks (MOFs) as drop-casted film electrodes that facilitate voltammetric detection of redox active neurochemicals in a multi-analyte solution. The device configuration comprises a glassy carbon electrode modified with a film of conductive MOF (M3HXTP2; M = Ni, Cu; and X = NH, 2,3,6,7,10,11-hexaiminotriphenylene (HITP) or O, 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP)). The utility of 2D MOFs in voltammetric sensing is measured by the detection of ascorbic acid (AA), dopamine (DA), uric acid (UA), and serotonin (5-HT) in 0.1 M PBS (pH=7.4). In particular, Ni3HHTP2 MOF demonstrated nanomolar detection limits of 63 ± 11 nM for DA and 40 ± 17 nM for 5-HT through a wide concentration range (40 nM – 200 µM). The applicability in biologically-relevant detection was further demonstrated in simulated urine using Ni3HHTP2 MOFs for the detection of 5-HT with nanomolar detection limit of 63 ± 11 nM for 5-HT through a wide concentration range (63 nM – 200 µM) in the presence of constant background of DA. The implementation of conductive MOFs in voltammetric detection holds promise for further development of highly modular, sensitive, selective, and stable electroanalytical devices. 
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