The present study investigates the significance of political party preferences in Finland by drawing upon two perspectives. Firstly, the research engages in the tradition of economic sociology, as one of its critical premises is to address political preference as an essential factor driving individual action. In this respect, this dissertation argues that political preference is strongly embedded in citizens' lives by also challenging the views of individuals as atomized rational actors. This argument is supported by the empirical articles, in which party preference was the influential factor associating and influencing different attitudinal and behavioural variables. Accordingly, Finnish parties are comprised of groups of similar supporters, which make the parties separate networks that contribute to the structuring of Finnish society. 

Secondly, the study provides a comprehensive picture of the Finnish political spectrum and political cleavages in the early 2000s, especially regarding the supporters and members of the major parties, namely the Centre Party of Finland (CPF), the National Coalition Party (NCP), the Finns Party (FP), the Social Democratic Party of Finland (SDP), the Green League (GL), and the Left Alliance (LA). The central context of the research revolves around the 2011 and 2015 parliamentary elections, in which the populist party, the FP, shaped Finnish political hegemony to such an extent that a review of the party features by means of adequate analyses and interpretations is required. 

To that end, the dissertation consists of five research articles, each of which addresses the multidimensionality of party preference from different perspectives using different datasets. Party preference is examined through party identification and party membership. The research utilised multiple nationwide survey datasets and unique datasets gathered from member-based surveys sampled from the membership registers of the six major parties. 

The first article compares the consumer preferences of party supporters by utilizing nationwide surveys. In accordance with the results, we concluded that party identification predicts citizens' perceived consumption expenditure significantly even after controlling for social background and temporal variance. The second article addresses the social trust of different party supporters in the Nordic context, taking advantage of European Social Surveys (ESS). Our findings supported hypotheses on low trust among the supporters of populist parties. Remarkably, confounding factors did not function similarly among the populists when compared to the supporters of other parties. In the third artcle, we studied how political fragmentation has progressed from the beginning of the 2000s to the present by examining terrorism risk perceptions with a nationwide time series. Our main finding was that political fragmentation has become radically prominent, especially with regard to the external threat perceptions of citizens. 

The last two articles focused on the members of the parties. In the former member-based article, we compared the members and supporters of parties and defined the parties' internal dynamics in the light of social status and essential ideological indicators. The latter memberfocused article and the final part of the dissertation compared the views of party members regarding societal risks. We targeted the comparison framework both between the parties and also within the different parties. Both member-based articles underlined the firsthypothesis regarding the meaning of party preference behind citizens' attitudes. Additionally, we found an increasing difference between the new ideological parties, namely the GL and the FP, which is associated with the realignment of the traditional parties as well. 

This dissertation summarises the original articles with an in-depth discussion upon the social mechanism of political party preference and the contemporary characteristics of the Finnish political spectrum. The dissertation suggests that the Finnish political spectrum is divided and that it is embedded in citizens' behaviour and attitudes. In this respect, it is possible to evaluate citizens' behaviours and attitudes through their political party preference in addition to demographic and other behavioural factors.