Assessing the Influence of Political Parties on Public Opinion: The Challenge from Pretreatment Effects

Abstract

Despite generations of research, political scientists have troubles pin-pointing the influence of political parties on public opinion. Recently, scholars have made headway in exploring whether parties in fact shape policy preferences by relying on experimental designs. Yet, the evidence from this work is mixed. I argue that the typical experiment faces a design problem that likely minimizes the extent to which parties apparently matter. Because parties have policy reputations, experimental participants may already know from real-world exposure to political debate where the parties stand before they are told in the experiment-they are "pre-treated". This study investigates how real-world political context interferes with party cue stimulus in experiments. In two experiments I show that two types of "pretreatment" from outside the experimentexposure-based and reputation-based-dramatically moderate the effects of party cues in experiments. Moreover, the politically aware participants-who are most likely to have been pretreated before entering the experiment-are the most sensitive to this interference from realworld context. Paradoxically, experimenters are most likely to find no effect of parties at the very time that their influence is strongest outside the experiment. These findings emphasize the importance of keeping real-world context in mind when designing and analyzing experiments on political communication effects and might help reconcile disparate results of previous party cue experiments.

Adapting to party lines: the effect of party affiliation on attitudes to immigration

“…It seems that this is exactly what we observe in the period under study in the Netherlands and Sweden. Even though we find that the effect of attitudes on party choice is stronger than vice versa, we conclude that attitudes and party preferences are thus characterised by a positive feedback loop (Slater 2007;Slothuus 2015).…”

“…After all, abundant evidence exists that voters take cues from the parties they support (Druckman et al 2013;Fortunato and Stevenson 2013;Popkin 1994;Slothuus 2015). Our study shows that Dutch and Swedish citizens' support for (especially nonmainstream) anti-and pro-immigration parties results in an adjustment of their views on immigration in the direction of their preferred party's position.…”

“…see Slothuus 2015 for an overview), and despite a large number of studies that focus on how anti-immigrant attitudes are affected by immigration frames (e.g. Brader et al 2008;Sniderman et al 2004) and media content (e.g.…”

“…For instance, Rooduijn et al (2016) show that voters not only express discontent by voting for populist parties, but, as a consequence, also become further dissatisfied. In a more general sense, this study thus reflects and underlines the growing scholarly awareness that citizens' world view, media exposure, and electoral decisions are dynamically linked by positive feedback loops (Slater 2007;Slothuus 2015; Van der Eijk et al 2007).…”

What can a party say? How parties' communication can influence voters' issue ownership perceptions

“…Thus, exactly because an issue-party combination is realistic and non-peripheral, internal validity can be threatened by pre-treatment effects implying that even those respondents who are not provided with a given stimulus (e.g., about the position of Party A on issue X) will have this information present in memory and use it when they evaluate the issue ownership of the party on the issue. In this case, the experiment would not show an effect of the stimulus even though it exists (see also Slothuus, 2015).…”