A 17-country laboratory experiment (Soroka, Fournier, and Nir, 2019) showed that, on average, people are more physiologically activated by negative than by positive television news, while simultaneously revealing substantial individual-level variation in this negativity bias — variation that country, culture, and media-system factors do not explain and that the most-studied candidate determinant, political ideology, does not account for either. The open problem is to identify the sources of this individual heterogeneity: which stable traits, transient states, information-processing predispositions, and contextual factors explain why some individuals react more strongly to negative news while a non-negligible minority react more strongly to positive news; whether these individual differences are stable over time or modifiable; whether they generalize beyond the original BBC World News stimuli to domestically produced news; and through which cognitive and emotional mechanisms (such as the diagnosticity of negative content and the arousal-versus-valence structure of affective responses) the variation arises.

Background

Why is news coverage around the world predominantly negative? One influential answer points to the demand side: a "negativity bias", the well-documented human tendency to attend to, react to, and weight negative information more strongly than positive information. Most evidence for this bias came from small Anglo-American samples using stimuli only loosely related to politics, so Soroka, Fournier, and Nir (2019) ran what remains the largest directly comparable psychophysiological study of reactions to news: 1,156 respondents in 17 countries on six continents watched seven randomly ordered BBC World News video stories while sensors recorded skin conductance (electrodermal activity capturing physiological activation, including the "orienting response" — the automatic shift of attention toward new or potentially threatening stimulation) and blood volume pulse, from which heart-rate variability was derived (specifically the RMSSD statistic, the root mean square of successive heartbeat differences, taken to index a mix of arousal (the intensity or activation dimension of an affective response) and attentiveness).

On average, participants showed the expected negativity bias: they were more physiologically activated and attentive during negative than positive stories. But the headline caveat is the focus of this problem: the estimated effect of story tone on physiological activation varies enormously across individuals. Some participants are far more activated by negative stories, others show little asymmetry, and some are more activated by positive content. Country-level context explains almost none of this variation — ANOVAs attribute only 1.5% (heart-rate) to 2.7% (skin conductance) of the variance in individual coefficients to country — and only a minority of country samples show a statistically significant average negativity bias on their own. In a later reanalysis of the skin-conductance data for the roughly 400 Anglophone participants, about a quarter exhibited coefficients indicating a statistically significant bias toward positive news (Soroka and Krupnikov, 2021).

Several candidate explanations for this heterogeneity exist but are untested or unsupported for physiological reactions to news. An evolutionary account, grounded in orienting-response research, predicts a universal bias and offers little room for individual differences. A cognitive account emphasizes the "diagnosticity" or "outlyingness" of negative content — the idea, formalized by Lamberson and Soroka (2018), that negative information is statistically unusual and therefore attention-worthy; if individuals differ in how they weigh diagnosticity, that could generate heterogeneity. A prominent political-psychology literature links stronger physiological reactions to negative stimuli to conservative ideology, but a direct comparative test across the same 17 countries failed to find strong support for the ideology link (Fournier, Soroka, and Nir, 2020). Work on the behavioral side of news selection has documented reliable individual differences — survey-measured negativity bias in news selection that partly persists over time and correlates with personality and attitudes (Bachleda et al., 2020), and valence-asymmetric learning biases that correlate with news choices (Soroka, Guggenheim, and Valentino, 2021) — but none of this identifies the determinants of the psychophysiological heterogeneity or links the two levels of measurement within the same individuals. The original study itself left open whether the individual differences are stable or mutable, and whether they would look the same for domestically produced rather than BBC news content.

Problem Statement

Identify and validate the sources of the substantial individual-level variation in negativity biases (the tendency to react more strongly to negative than to positive content) in psychophysiological reactions to news observed by Soroka, Fournier, and Nir (2019). The problem has five components: (i) identify measurable individual-level factors — stable traits, transient states, information-processing predispositions, or contextual factors such as the personal information environment — that account for a nontrivial, replicable share of the between-person variation in the coefficient linking news-story tone (the negative-versus-positive emotional valence of the content) to physiological activation measured by at least one of skin conductance (electrodermal activity) or heart-rate variability; (ii) establish whether these individual differences are stable over time or modifiable by news diet, and distinguish genuine individual differences from measurement error; (iii) determine whether the heterogeneity generalizes beyond the identical BBC World News stimuli used in the original study to domestically produced news content; and (iv) disentangle the cognitive and emotional mechanisms — such as the diagnosticity or 'outlyingness' of negative content and the arousal-versus-valence structure of affective responses (whether reactions track how activating or how pleasant the content is) — through which the variation arises; and (v) quantify how large the minority that reacts more strongly to positive than to negative news is outside the original Anglophone BBC-stimulus sample, and establish whether positive news is attention-grabbing, in the physiological sense of producing activation and attentiveness, for a non-negligible portion of the news audience, as opposed to the variation being noise around a universal negativity bias. Each of the five components is resolved when the answer states a definite result for it — a proposed factor, mechanism, or quantity; a proposed determination on the component's question, such as whether the individual differences are stable or modifiable or whether the heterogeneity generalizes; or a proposed null result — together with the evidence or design, existing or newly proposed, by which that result would be validated; the result need not already be supported by existing evidence, and collecting new data is not required.

References

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