Cited by 164Social Media and PoliticsMedia Influence and PoliticsMisinformation and Its Impacts

Do Search Algorithms Endanger Democracy? An Experimental Investigation of Algorithm Effects on Political Polarization

Open access
Cho, Jaeho, Ahmed, Saifuddin, Hilbert, Martin, Liu, Billy, Luu, Jonathan·2020·Journal of Broadcasting & Electronic Media

Abstract

This study examines algorithm effects on user opinion, utilizing a real-world recommender algorithm of a highly popular video-sharing platform, YouTube. We experimentally manipulate user search/watch history by our custom programming. A controlled laboratory experiment is then conducted to examine whether exposure to algorithmically recommended content reinforces and polarizes political opinions. Results suggest that political self-reinforcement, as indicated by the political emotion-ideology alignment, and affective polarization are heightened by political videos – selected by the YouTube recommender algorithm – based on participants’ own search preferences. Suggestions for how to reduce algorithm-induced political polarization and implications of algorithmic personalization for democracy are discussed.

Verified 2026-10-11 · 1 reference not checked yet

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Registry

Crossref · 10.1080/08838151.2020.1757365

Cites

61 of 62 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

7 of 54 cited sources checked · 2 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Existing evidence suggests that the pattern of individuals' information seeking and consumption is more nuanced and multifaceted than assumed in the notion of selective exposure and homophily.

    “Existing evidence suggests that the pattern of individuals' information seeking and consumption is more nuanced and multifaceted than assumed in the notion of selective exposure and homophily.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Beam, 2014 source
    • cites Garrett et al., 2013 source
    • cites Hart et al., 2009 source

      The Results (page unavailable) show that information selection depends on utility: participants sometimes favored information that challenged their existing views. This supports a more nuanced account of selective exposure, but the paper does not assess homophily, so that part of the comparison is unsupported. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Findingown data

    Affective polarization is heightened by political videos selected by the YouTube recommender algorithm based on participants' own search preferences.

    “Results suggest that political self-reinforcement, as indicated by the political emotion-ideology alignment, and affective polarization are heightened by political videosselected by the YouTube recommender algorithmbased on participants' own search preferences.”
    Quote in the paperSubstantial claim
  • Findingown data

    Political self-reinforcement, indicated by political emotion-ideology alignment, is heightened by political videos selected by the YouTube recommender algorithm based on participants' own search preferences.

    “Results suggest that political self-reinforcement, as indicated by the political emotion-ideology alignment, and affective polarization are heightened by political videosselected by the YouTube recommender algorithmbased on participants' own search preferences.”
    Quote in the paperSubstantial claim
  • Findingown data

    Ideas perceived to be discussed in one's social circles, if adopted as search terms by the user, weaken reinforcing effects of algorithms.

    “As shown in the results, ideas perceived to be discussed in one's social circles, if adopted as search terms by the user, weaken reinforcing effects of algorithms.”
    Quote in the paperSubstantial claim
  • Findingown data

    The pattern of stronger ideology-emotion alignment in the 'self' condition than in the 'social' condition is particularly pronounced for negative emotions such as anger and sadness.

    “This pattern is particularly pronounced for negative emotions such as anger and sadness.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 24
  • Classified as probably not a substantial claim. 40
  • The quote only partly states this claim. 2
  • May combine two claims.

    Premisecitation

    Although people do not necessarily avoid attitude-discrepant messages, attitude-consistent messages that resonate with them and confirm their desired conclusions are more likely to be preferred.

    “Although people do not necessarily avoid attitude-discrepant messages (Ahn et al., 2014;Beam, 2014;Garrett et al., 2013), it is more likely that attitude-consistent messages that resonate with them and confirm their desired conclusions are preferred (Feldman et al., 2018;Gentzkow & Shapiro, 2011;Stroud, 2011).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Feldman et al., 2018 source
    • cites Gentzkow & Shapiro, 2011 source

      The Introduction reports that conservatives and liberals have somewhat different ideological exposure in their online news diets, consistent with some selection of attitude-consistent outlets. But Section 6 says the study cannot directly observe which stories people choose within those outlets, and the Introduction says its evidence does not address how people translate content into beliefs. It therefore does not establish that messages are preferred because they resonate with readers or confirm desired conclusions. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites Stroud, 2011 source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Recommender algorithms installed on online platforms help users efficiently access the information they are looking for while also reducing information overload.

    “Recommender algorithms installed on online platforms help users efficiently access the information they are looking for while also reducing information overload (Hannak et al., 2013;Lazer, 2015).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Hannak et al., 2013 source

      The Introduction describes personalized search as ranking webpages a user is likely to be interested in more highly, which supports the information-finding part of the claim in principle. But the Recommendations section says the study did not determine whether personalization improved users’ search experiences, and the passages do not establish that it reduces information overload. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites Lazer, 2015 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Based on some kind of input, recommender systems select a set of items from a large pool of available items and recommend a list of information links for users to choose.

    “Based on some kind of input, recommender systems select a set of items from a large pool of available items and recommend a list of information links for users to choose (Resnick & Varian, 1997).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Resnick & Varian, 1997 source

      The Recommender Systems section says systems take recommendations as inputs, aggregate them, and direct them to recipients; it also describes recommending interesting items. But it does not characterize recommender systems generally as selecting from a large pool and presenting users with a list of information links. It describes links as one possible type of recommendation alongside books, movies, and other items. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Classified as probably not a substantial claim.

    Premisecitation

    There are two distinct but coexisting human motivations that account for citizens' choice and consumption of political information: directional versus accuracy.

    “It is proposed that there are two distinct but coexisting human motivations that account for citizens' choice and consumption of political information: directional vs. accuracy (Kunda, 1990, or defensive vs. accuracy in Hart et al., 2009, or cognitive consistency vs. understanding in Holbert et al., 2013).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Kunda, 1990 source
    • cites Hart et al., 2009 source
    • cites Holbert et al., 2013 source
  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Ideological reinforcement was examined by the correlation between affective candidate evaluations and political ideology, which quantifies the extent to which the two are aligned as a function of experimental treatment.

    “First, ideological reinforcement was examined by the correlation between affective candidate evaluations and political ideology which quantifies the extent to which the two are aligned as a function of the experimental treatment (Cho et al., 2018).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Cho et al., 2018 source

      The Results describe testing whether political expression strengthens the relationship between party identification and political opinions, and the Measures section describes affective ratings of candidates (page numbers unavailable). But the paper tests that relationship with regression models and tracks changes in candidate preference; it does not describe correlating candidate evaluations with ideology as a function of experimental treatment. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • May combine two claims.

    Premisecitation

    People generally do not necessarily avoid counter-attitudinal information, and further seek such information when they believe it helps them understand and be accurate on the situation at hand.

    “People, in general, do not necessarily avoid counter-attitudinal information (Beam, 2014;Garrett et al., 2013), and further seek such information when they believe it helps them understand and be accurate on the situation at hand (Hart et al., 2009;Holbert et al., 2013;Kunda, 1990).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Beam, 2014 source
    • cites Garrett et al., 2013 source
    • cites Hart et al., 2009 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    In the ANCOVA model, political interest added as a random factor interacting with condition was not significant.

    “in the ANCOVA model, political interest was added as a random factor and specified to interact with the fixed factor (i.e., conditions), and the results for the interaction were not significant.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims. The quote only partly states this claim.

    Findingown data

    For fear, joy, hope, and overall valence (feeling thermometer), the ideology-emotion alignment was stronger in the 'self' condition than in the 'social' condition, but these differences were not statistically significant.

    “A similar, albeit not statistically significant, the pattern was observed for all other measures of emotion.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The three-way interaction (ideology x experimental condition x interest) predicting post-exposure candidate evaluation, with pre-exposure candidate evaluation controlled, was not significant; likewise, two-way interactions involving interest were not significant.

    “The three-way interaction was not significant; likewise, two-way interactions involving interest were not significant either.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The experiment showed an overall pattern of opinion reinforcement and polarization after exposure to algorithm-recommended content, especially when algorithms were fed with self-generated search terms.

    “The results of our experiment showed an overall pattern of opinion reinforcement and polarization after exposure to algorithm-recommended content, especially when algorithms were fed with self-generated search terms.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    With accuracy motivation, individuals often cross ideological lines and glean, or at least do not avoid, information from the other side of the political spectrum.

    “With this motivation, individuals often cross ideological lines and glean (or at least do not avoid) information from the other side of the political spectrum (Garrett et al., 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Garrett et al., 2013 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The accuracy motivation drives individuals to seek information they expect to be of high informational value.

    “In contrast, the accuracy motivation drives individuals to seek information that they expect to be of high informational value.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Garrett et al., 2013 source
  • May combine two claims.

    Premisecitation

    Algorithms are naturally designed to operate with, not against, human tendencies, one of which is that people feel more comfortable with consistency and confirmation.

    “The underlying reason for the reinforcing tendency of algorithms is that algorithms are naturally designed to operate with, not against, human tendencies, one of which is that people feel more comfortable with consistency and confirmation (Kunda, 1990).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kunda, 1990 source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The input to recommender systems can be a search term or some other preference statement, and selection is traditionally based on the personal history of the user (content-based filtering), the cross-section of other users (collaborative filtering), or a mix of both.

    “The input can be in the form of a search term or some other preference statement, and the selection is traditionally based on the personal history of the user (content-based filtering), or the cross-section of other users (collaborative filtering), or a mix of both (Balabanović & Shoham, 1997).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Balabanović & Shoham, 1997 source
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    As data about a user's information search and consumption accumulates, algorithms' ability to personalize is sharpened in subsequent searches.

    “As data about information search and consumption for a specific user accumulates, algorithms' ability to personalize is sharpened in subsequent searches.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    User-oriented recommendations increase the likelihood of consumption (clicking) by users because the recommended messages fit their interests.

    “Such user-oriented recommendations, in turn, increase the likelihood of consumption (clicking) by the users, as the recommended messages fit their interests.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisereasoning

    To the extent that user inputs reflect existing political preferences, search engine use could eventually lead to a filter bubble: a like-minded information environment created by personalized algorithmic recommendations and resulting segregation of users in their ideological and political views.

    “To the extent that user inputs (e.g., search terms, clicks, etc.) reflect their existing political preferences, search engine use could eventually lead to the so-called”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Pariser, 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisecitation

    The directional (or defensive) motivation leads to selective exposure, encouraging individuals to seek information or news sources congenial to their existing attitudes.

    “The directional (or defensive) motivation leads to selective exposure, encouraging individuals to seek information (or news sources) that they believe is congenial to their existing attitudes (Iyengar & Hahn, 2009;Stroud, 2011).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Iyengar & Hahn, 2009 source
    • cites Stroud, 2011 source
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Affective polarization was measured as the difference between affective evaluations of the two candidates, which captures the degree to which attitudes about in-group and out-group candidates diverge.

    “Second, affective polarization was measured as the difference between affective evaluations of the two candidates which captures the degree to which attitudes about in-group and out-group candidates diverge.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    Algorithmic recommendations personalized by user behavior data, if unchecked, have the potential to solidify personal political convictions and encourage polarized opinions.

    “Thus, algorithmic recommendations personalized by user behavior data, if unchecked, has the potential to solidify personal political convictions and encourage polarized opinions.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The control condition videos were a baseline control because they were what a user searching the same topic without a specific search/watch history would encounter per YouTube's recommendation at the time.

    “These videos were used as a baseline controlsince they were the videos that a user who was in search for videos about the same topic (i.e., 410 the presidential election of past week)but did not have a specific search/watch history would encounter, per YouTube's recommendation at the time.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    Exposure to information that is more diverse or less agreeable in relation to one's own thoughts and beliefs could lessen self-reinforcement and opinion polarization.

    “Exposure to information that is more diverse or less agreeable in relation to one's own thoughts and beliefs could then lessen selfreinforcement and opinion polarization (Mutz, 2006).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mutz, 2006 source
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Non-self-report, behavioral data about user interests and beliefs allow algorithms to hone further recommendations.

    “Non-self-report, behavioral data about user interests and beliefs allow algorithms to hone further recommendations.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The terms that users enter for their online searches are reflective of what they care about and what they believe.
  • May combine two claims.

    Premisecitation

    Attitude-consistent information, or information from a like-minded source, is often viewed as more credible and of higher quality, and this perception encourages consumption and facilitates processing.

    “Further, attitude-consistent information (or information from a like-minded source) is often viewed as more credible and of higher quality, and this perception not only encourages consumption of the information but also facilitates the processing of it (Miller et al., 1993).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Miller et al., 1993 source
  • May combine two claims.

    Interpretationown data

    Due to programmed responsiveness to past user interests and preferences, algorithms serve as a confirmatory communication partner or an echo chamber that reassures and reinforces users' prior beliefs and fosters extremism, as observed in politically homogeneous communication networks.

    “Due to the programmed responsiveness to past user interests and preferences, algorithms serve as a confirmatory communication partner or an echo chamber that reassures and reinforces users' prior beliefs and fosters extremism, as observed in the case of politically homogeneous communication networks.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Exposure to like-minded information via personalized algorithmic recommendations shapes users' political opinion in two ways: ideological reinforcement and affective polarization.

    “When viewed from the broader literature in political psychology, this research on selective exposure suggests two ways how exposure to likeminded information via personalized algorithmic recommendations would shape users' political opinion: ideological reinforcement and affective polarization.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    Ideological reinforcement, as indicated by political emotion-ideology alignment, is heightened by political videos selected by the YouTube recommender algorithm based on participants' own search preferences and is muted to some degree if perceived preferences of participants' online social circle are used as inputs.

    “This suggests that ideological reinforcement, as indicated by the political emotion-ideology alignment, is heightened by political videos selected by the YouTube recommender algorithm based on participants' own search preferences and is muted to some degree if perceived preferences of participants' online social circle are used as inputs.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Personalization by users' past behavior is a key mechanism of online search and recommender algorithms.
    • Rests on an assumption: Algorithmic recommendations are a product of users' search terms and subsequent consumption of information.
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationreasoning

    Algorithmic recommendations are largely an outcome of iterative interactions between users and algorithms, and the recommendations differ depending on what search terms users enter.

    “To summarize, algorithmic recommendations are largely an outcome of iterative interactions between users and algorithms, and the algorithmic recommendations are different depending on what search terms users enter.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    If a user's search term selection goes beyond her routine repertoire, algorithms would provide more diverse recommendations.

    “In contrast, if a user's search term selection somehow goes beyond her routine repertoire, algorithms would provide more diverse recommendations.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Social endorsement reduces partisan selectivity toward like-minded information, so social media use is an opportunity to increase users' exposure to a variety of news and politically diverse information.

    “As social endorsement reduces partisan selectivity toward like-minded information, social media use is an opportunity to”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Messing & Westwood, 2014 source
  • Classified as probably not a substantial claim.

    Premisecitation

    Human memory is a network of interconnected cognitive and affective constructs.

    “First, schema theory in social cognition research has long suggested that human memory is a network of interconnected cognitive and affective constructs (Anderson & Bower, 1973;Lodge & Stroh, 1993).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Anderson & Bower, 1973

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Lodge & Stroh, 1993 source
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    If individuals are motivated to explore ideas encountered in their social networks, their search behaviors would likely be less bounded by their own interests and preferences and thus train algorithms on their own.

    “However, if individuals are motivated to explore ideas that they encounter in their social networks, their search behaviors would likely be less bounded by their own interests and preferences and thus train algorithms on its own.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Interpretationcitation

    Given the human tendency toward psychological consistency, cognitive salience of counter-attitudinal ideas in the user mind would not be strong enough to drive routine searches online.

    “Yet, given the human tendency toward psychological consistency (Kunda, 1990), cognitive salience of counter-attitudinal ideas in the user mind would not be strong enough to drive routine searches online.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kunda, 1990 source
  • May combine two claims.

    Interpretationreasoning

    Algorithms, although helping users navigate a massive amount of information, add to political selectivity that separates people from contradictory views.

    “Viewed in this light, algorithms, although helping users navigate a massive amount of information, add to political selectivity that separates people from contradictory views.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The baseline is dynamic, as the current YouTube environment simultaneously affects both personalized recommendations and trending videos.

    “It is a dynamic baseline, as the current YouTube environment simultaneously affects both the personalized recommendations and the trending videos.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    A general conclusion of past research on selective exposure is that exposure to confirmatory information strengthens existing opinions.

    “A general conclusion of past research on selective exposure is that exposure to confirmatory information strengthens existing opinions (Stroud, 2011;Sunstein, 2001;Tewksbury & Riles, 2015).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Stroud, 2011 source
    • cites Sunstein, 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Tewksbury & Riles, 2015 source
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    If searches are crafted based on one's perception or memory of ideas shared in social networks, the resulting algorithmic recommendations would likely contain a wider range of information or perspectives.

    “That is, if searches are crafted based on one's perception (or memory) of ideas shared in social networks, the resulting algorithmic recommendations would likely contain a wider range of information or perspectives.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    If information search is driven by a user's own perspectives, algorithms recommend information the user would agree with.

    “If, as suggested by the notion of selective exposure, information search is driven by a user's own perspectives, algorithms recommend information the user would agree with.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    The heightened selectivity from user-algorithm interaction induces a personally tailored information environment for each user, which in turn shapes the user's opinion.

    “The heightened selectivity as a result of the user-algorithm interaction induces a personally tailored information environment for each user which, in turn, shapes the user's opinion.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    Individuals' political opinion is often organized in a coherent structure of attitudes in which domain-specific opinions are grounded in broader political beliefs such as ideology.

    “In light of the schema theory, scholars of public opinion have posited that individuals' political opinion is often organized in a coherent structure of attitudes in which domain-specific opinions are grounded in a broader set of political beliefs (or”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Conover & Feldman, 1984 source
    • cites Converse, 1964

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Hurwitz & Peffley, 1987 source
  • May combine two claims.

    Premisecitation

    If a person is exposed to counter-attitudinal information, her attitudinal ambivalence would increase, thereby reducing affective polarization.

    “If a person is exposed to counter-attitudinal information, her attitudinal ambivalence would increase, thereby reducing affective polarization (Huckfeldt et al., 2004;Mutz, 2006).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Huckfeldt et al., 2004 source
    • cites Mutz, 2006 source
  • Classified as probably not a substantial claim. May combine two claims. The quote only partly states this claim.

    Study design and conductreasoning

    The first ranking identifies self search preference while the second taps into social preference at least in participants' perception.

    “The first identifies”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Consumption of proattitudinal information recommended by algorithms gives reinforcing feedback to algorithms, confirming users' preferences and validating and enhancing algorithmic personalization.

    “Then, the consumption of proattitudinal information recommended by the algorithms gives reinforcing feedback to the algorithms, confirming the users' preferences and thus validating and enhancing algorithmic personalization.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The way search preferences were measured (choosing topics from a pre-selected set) only allows participants to indicate their preferences constrained within the list.

    “this approach only allows participants to indicate their preferences constrained within the list.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The relatively open social networks of college students likely lead to a wider diversity of search terms gleaned from their online friends, which could potentially explain the results at least in part.

    “The relatively open social networks likely lead to a wider diversity of search terms gleaned from their online friends, which could potentially explain the results at least in part.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The results should be interpreted as showing algorithm effects when users are somehow motivated to explore ideas that they think their friends care about.

    “The results should be interpreted as showing algorithm effects when users are somehow motivated to explore ideas that they think their friends care about.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given

    This study utilized an actual real-world, not proxy, algorithm on a highly popular online platform, which greatly enhances the external validity and relevance of the findings.

    “this study utilized an actual real-world, not proxy, algorithm on a highly popular online platform, a fact that greatly enhances the external validity and relevance of the findings.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation

    Compared to the average population, college students are in general more active on the Internet and tend to be friends with a more diverse group of people on their online social networks.

    “As compared to the average population, college students are in general more active on the Internet and tend to be friends with a more diverse group of people on their online social networks (Pfeil et al., 2009).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Pfeil et al., 2009 source
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    We cannot draw a firm conclusion from a single experiment with college students.

    “we cannot draw a firm conclusion from a single experiment with college students.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    Coupled with this research, our results suggest that algorithm effects on opinion reinforcement and polarization are conditional and would be better understood when considering how and to what extent cross-cutting exposure, as opposed to selective exposure, occurs.

    “Coupled with this research, our results suggest that algorithm effects on opinion reinforcement and polarization are conditional and would be better understood when considering how and to what extent cross-cutting exposure, as opposed to selective exposure, occurs.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    The complex and dynamic algorithmic systems handling big data make it difficult to predict outcomes.

    “the complex and dynamic algorithmic systems handling big data make it difficult to predict outcomes (Lazer, 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Lazer, 2015 source
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    The unique situation of the just-finished presidential election might amplify the reinforcing effects of algorithmic personalization.

    “This unique situation might amplify the reinforcing effects by algorithmic personalization as perhaps participants already have strong opinions and information recommended by algorithms might contain partisan or polarizing cues.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The overall body of available information online about the election and candidates was highly polarized at the time when this experiment was conducted.
    • Rests on an assumption: The opinion targets (presidential candidates) are much more salient and polarizing in participants' minds than any other issues.
  • May combine two claims.

    Interpretationown data

    When it comes to controversial social and political topics, algorithmic personalization could also serve as an echo chamber strengthening users' prior convictions and thus aggravating the existing political chasm in society.

    “When it comes to controversial social and political topics, algorithmic personalization could also serve as an echo chamber strengthening users' prior convictions and thus aggravating the existing political chasm in society.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    User opinion in this study was operationalized as affective assessments of two major candidates of the presidential election that was just finished.

    “user opinion, in this study, was operationalized as affective assessments of two major candidates of the presidential election that was just finished.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The first recommended video was selected based on previous evidence suggesting that users often click on top-ranked search results.

    “The first recommended video was selected based on previous evidence suggesting that users often click on top-ranked search results(Bakshy et al., 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bakshy et al., 2015 source
55 of 55
  • The authors state this as an assumption.

    The terms that users enter for their online searches are reflective of what they care about and what they believe.

    “A key assumption is that the terms that users enter for their online searches are reflective of what they care about and what they believe.”
  • The paper relies on this without support.

    Personalization by users' past behavior is a key mechanism of online search and recommender algorithms.

    “Although personalization by users' past behavior is a key mechanism, the complex and dynamic algorithmic systems handling big data make it difficult to predict outcomes (Lazer, 2015).”
  • The paper relies on this without support.

    Algorithmic recommendations are a product of users' search terms and subsequent consumption of information.

    “since algorithmic recommendations are a product of users' search terms and subsequent consumption of information.”
  • The paper relies on this without support.

    The overall body of available information online about the election and candidates was highly polarized at the time when this experiment was conducted.

    “the overall body of available information online about the election and candidates was also likely highly polarized at the time when this experiment was conducted.”
  • The paper relies on this without support.

    The opinion targets (presidential candidates) are much more salient and polarizing in participants' minds than any other issues.

    “It is thus highly likely that the opinion targets (i.e., presidential candidates) are much more salient and polarizing in participants' minds than any other issues.”
  • The paper relies on this without support.

    Online platforms operating in different contexts program and run their algorithms differently.

    “However, online platforms operating in different contexts program and run their algorithms differently.”
  • The paper relies on this without support.

    Online search and recommender algorithms are essentially black boxes.

    “This is why online search and recommender algorithms are essentially black boxes.”
7 of 7

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • ConsistentF(2, 104) = 4.47reported p < .05 · recomputed p = .014

    “F(2, 104) = 4.47, p < .05”

1 of 1

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Anger correlation is not negative in every condition

    Minor

    The paper says the anger-ideology correlation is negative across all conditions, but reports a positive correlation for the control condition.

  • Feeling-thermometer errors are labeled as standard deviations

    Minor

    The results text labels the values accompanying the three feeling-thermometer means as standard deviations, whereas Table 2 identifies its parenthesized values as standard errors.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Fiske S. T., 1986, Handbook of motivation and cognition: Foundations of social behavior, 167
  2. Rosenberg M. J., 1960, Attitude organization and change, 1
  3. Sunstein C. R., 2001, Echo chambers: Bush v. Gore, impeachment, and beyond
  4. Zuiderveen Borghesius F., 2016, Internet Policy Review, 5, 1

Cited by

Sorted by citations

Authors
Cho, J., Ahmed, S., Hilbert, M., Liu, B., & Luu, J.
Affiliations
  • University of California, Davis (US)
  • Nanyang Technological University (SG)
  • Software Engineer, Sacramento, CA, USA
  • Software Engineer, San Diego, CA, USA
Corresponding author
Cho, Jaeho
Venue
Journal of Broadcasting & Electronic Media
Published
2020-04-27
Volume
64
Issue
2
Pages
150-172
ISSN
  • 0883-8151 (ISSN-L)
  • 1550-6878
OpenAlex
W3018249611
Cited by
164
References
54
Citations by year
2026: 21 · 2025: 33 · 2024: 33 · 2023: 38 · 2022: 20 · 2021: 17 · 2020: 2
FWCI
23.10
Type
journal article
Language
en
Open access
Locations
  • Journal of Broadcasting & Electronic Media (publishedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Topics
  • Social Sciences › Communication › Social Media and Politics
  • Social Sciences › Sociology and Political Science › Media Influence and Politics
  • Social Sciences › Sociology and Political Science › Misinformation and Its Impacts
Keywords
algorithmic recommendation, political polarization, YouTube, affective polarization, algorithmic personalization, democracy

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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