📄 social_science

Knocking on the Wrong Door: Partisan Canvassing and Asymmetric Belief Updating in Great Britain

Using a decade of British Election Study data, this paper demonstrates that door-to-door canvassing by a voter's own party significantly shifts their perceptions toward that party's stance and widens perceived ideological distance, whereas contact from rival parties has negligible effects, suggesting that partisan canvassing may inadvertently reinforce perceived polarization.

Original authors: Yen-Chieh Liao, Li Tang

Published 2026-08-28

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Yen-Chieh Liao, Li Tang

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

In the landscape of modern democracy, a persistent question haunts political scientists: do election campaigns actually change what people believe, or do they simply echo what voters already think? For decades, the prevailing wisdom suggested that campaigns rarely convert opponents. Instead, they were thought to act as a mirror, reflecting and reinforcing the preferences voters already held, while doing little to alter the fundamental choices people make at the ballot box. However, this view leaves a crucial gap in our understanding. Even if a campaign cannot convince a voter to switch sides, it might still change how that voter perceives the world around them. Specifically, it might alter how accurately they understand where political parties actually stand on the issues. This distinction matters because a democracy relies on voters having a reasonably accurate map of the political terrain. If voters are misinformed about where their own party stands, or if they believe the gap between opposing parties is wider than it truly is, the health of the entire system is at risk.

Researchers Yen-Chieh Liao and Li Tang set out to investigate this specific dynamic by examining the mechanics of door-to-door canvassing in Great Britain. They focused on a phenomenon known as "identity-weighted belief updating," a concept suggesting that people do not process political information like neutral computers. Instead, they filter messages through the lens of their own political identity. When a voter hears from someone who shares their party affiliation, they tend to trust the message and adjust their beliefs accordingly. Conversely, when the same voter hears from someone representing a rival party, they tend to dismiss the information entirely, regardless of its accuracy. To test this, the team analyzed a massive, decade-long dataset from the British Election Study, tracking over 44,000 individuals across four general election cycles between 2014 and 2024. This longitudinal approach allowed them to see how the same people's perceptions shifted over time as they were contacted by different political groups.

The study revealed a clear and striking pattern. When voters were contacted by their own party, their understanding of that party's actual position improved. The more channels through which they were contacted—whether by phone, letter, email, or a personal visit—the more their misconceptions were corrected. For instance, if a supporter had previously believed their party was more moderate than it actually was, the contact helped nudge their perception closer to the truth. However, the story changed completely when the contact came from the opposing party. Whether a Conservative supporter was contacted by Labour canvassers, or a Labour supporter by Conservatives, the effect was virtually non-existent. The voters simply did not update their beliefs based on these rival messages. The data showed that rival-party contact had no statistically significant impact on what voters thought about the opposing side's position.

This one-sided correction led to a surprising and somewhat troubling secondary effect. Because voters were becoming more accurate about their own party's stance while their views on the rival party remained frozen in place, the perceived distance between the two major parties grew larger. In the minds of these voters, the political landscape appeared more divided than it actually was. The researchers found that this increase in perceived polarization was particularly strong among supporters of the Labour Party, whose initial misconceptions about their own party's position were often more pronounced. The effect was also more dramatic for "weak partisans"—those who identified with a party but not with deep intensity. These individuals, who started with the least accurate understanding of where their party stood, showed the largest improvements in accuracy after being contacted. In contrast, strong partisans, who already had a fairly clear picture of their party's position, showed much smaller shifts.

The researchers suggest that this creates a paradox for democratic campaigns. On one hand, the work of canvassers is successful in making voters better informed about the party they support. On the other hand, this very success inadvertently deepens the sense of division in the electorate. By correcting the internal map of one side without touching the map of the other, the campaign makes the two sides look further apart than they really are. The study indicates that this is not a result of voters being tricked or manipulated, but rather a natural consequence of how human beings process information when their political identity is at stake. They accept the signals from their own team and ignore the signals from the opposition.

The findings also highlight a potential inefficiency in how political parties spend their resources. The data showed that the voters who needed the most correction—the weak partisans with the most inaccurate views—were often the ones who benefited the most from contact. Yet, campaigns frequently focus their mobilization efforts on strong partisans, who are already well-informed and less likely to change their minds. This suggests that parties might be "knocking on the wrong doors," investing time and energy in voters who do not need persuasion, while leaving the most misinformed citizens untouched. The study does not claim that these campaigns change who people vote for, but it does show that they significantly alter the mental landscape in which those votes are cast, creating a citizenry that is simultaneously better informed about its own side and more convinced that the political divide is unbridgeable.

Technical Summary: Knocking on the Wrong Door: Partisan Canvassing and Asymmetric Belief Updating in Great Britain

Problem Statement
While the conventional wisdom in political science suggests that campaign contact has minimal persuasive effects on vote choice, this consensus leaves open the question of whether such contact alters voters' beliefs about party positions. Existing literature indicates that voters frequently misperceive where parties stand on the ideological spectrum, and these misperceptions influence democratic accountability and affective polarization. However, it remains unclear how door-to-door canvassing shapes these informational gaps, particularly whether the effects depend on the partisan alignment between the messenger (canvasser) and the recipient. The authors investigate whether campaigns selectively correct misperceptions among co-partisans while failing to influence opponents, potentially leading to unintended consequences for perceived polarization.

Methodology
The study employs a longitudinal panel design using data from the British Election Study (BES) Internet Panel, covering waves 3 through 29 (2014–2024). This dataset tracks over 44,000 person-wave observations across four general election cycles, allowing for within-respondent comparisons of belief updating over time.

Sample: The analysis is restricted to respondents identifying with the Conservative or Labour parties who have non-missing data on contact and left-right self-placement.
Dependent Variables:
1. Own-Party Misperception: The absolute distance between a respondent's perceived position of their preferred party and the party-year mean perception (serving as a proxy for the "true" position).
2. Perceived Polarization: The absolute distance between a respondent's perceived positions of the Conservative and Labour parties.
Independent Variables: Contact intensity is measured by the number of channels through which a respondent was contacted by their own party and the rival party. Channels include telephone, letters/leaflets, home visits, street canvassing, email, SMS, and other means. The authors distinguish between "Total Contact" (all channels) and "Personal Contact" (direct, interactive channels like calls and visits).
Empirical Strategy: The authors estimate individual fixed-effects models to isolate the effect of canvassing exposure. The baseline specification regresses misperception and perceived polarization on own-party and rival-party contact, controlling for time-varying covariates (left-right self-placement, rival contact) and including individual and year fixed effects. Standard errors are clustered at the respondent level.

Theoretical Framework
The authors develop a model of identity-weighted belief updating. Drawing on the spatial tradition and partisan motivated reasoning, the model posits that voters update their beliefs based on signals from canvassers, but the weight assigned to these signals ( $\kappa$ ) depends on the partisan source.

Own-party signals are trusted ( $t_H$ high), leading to belief updating toward the party's actual position.
Rival-party signals are discounted ( $t_L \approx 0$ ) due to identity-protective cognition or strategic skepticism, resulting in negligible updating.
Heterogeneity: The model predicts that the magnitude of belief correction is proportional to the initial level of misperception. Consequently, weak partisans (who hold noisier priors) should exhibit larger treatment effects than strong partisans.
Polarization Mechanism: If voters hold "centrist-biased" priors (placing their own party closer to the center than it actually is), own-party contact corrects this bias outward toward the true position. Since rival-party perceptions remain unchanged (due to discounting rival signals), the perceived distance between the two parties widens, increasing perceived polarization.

Key Results

Asymmetric Belief Updating: Own-party contact significantly reduces misperception of the own party's position. For Conservative supporters, each additional contact channel reduces misperception by 0.026 points; for Labour supporters, the reduction is 0.034 points. In contrast, rival-party contact has no statistically significant effect on misperception for either group.
Heterogeneity by Partisan Strength: The effect of own-party contact is substantially larger for weak partisans than for strong partisans. Among Conservatives, the effect for weak partisans is nearly three times larger than for strong partisans; among Labour supporters, it is more than four times larger. This supports the model's prediction that correction scales with the magnitude of initial error.
Increased Perceived Polarization: Own-party contact leads to an increase in perceived ideological polarization. For Labour supporters, own-party contact significantly widens the perceived gap between the two major parties. The effect is positive but less precisely estimated for Conservatives. This finding supports the proposition that selective correction of own-party perceptions (moving them away from a centrist bias) without updating rival perceptions expands the perceived ideological distance.
Contact Type: Personal contact channels (telephone, home visits, etc.) show similar directional effects to total contact, with coefficients that are substantively meaningful, suggesting that direct interaction carries high source credibility.

Significance and Claims
The paper claims to demonstrate that while campaigns may not change vote choices, they fundamentally alter the informational landscape for voters. The primary contribution is the identification of an unintended consequence of democratic campaigns: partisan canvassing leaves voters better informed about their own party's position but simultaneously leads them to perceive the political landscape as more polarized than it actually is.

The authors argue that this occurs because campaigns selectively correct misperceptions within partisan groups while failing to bridge cross-partisan divides. This creates a paradox where voters become more accurate regarding their own side but more extreme in their perception of the opposition's distance. The findings suggest that the "knocking on the wrong door" metaphor applies not just to mobilization efficiency, but to the distributional consequences of information: campaigns reinforce within-group alignment while leaving cross-partisan divides intact or even widening them. The authors note that these effects are particularly pronounced among weak partisans, suggesting that current mobilization strategies targeting strong partisans may be investing resources in voters who need correction the least, while the most misinformed remain untouched.

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