横山 智哉

Motivated by a previous finding that single-party cues have no effect in Japan and by the increasing ‘presidentialization’ of Japanese politics, the present study examined whether the use of prime minister cues in place of single-party cues helps Japanese voters form policy preferences. In addition, to probe the effect of party cues that are unique to multiparty systems, the effect of multiple-party cues, which indicate that a policy is supported by multiple rather than single ideologically distinct parties, was investigated. The results of a survey experiment showed that while prime minister cues are not utilized by the supporters of incumbent parties, the supporters of opposition parties demonstrated significantly reduced approval of a policy when there was an indication that the prime minister supported it. The effect of prime minister cues on opposition supporters was stronger than that of Liberal Democratic Party cues, suggesting that leader cues are effective in Japan. Furthermore, a cue indicating that ideologically distinct parties support a policy enhances approval for that policy among the public, which suggests that multiple-party rather than single-party cues are informative in multiparty systems. Theoretical implications are discussed.

For voters with bounded rationality to emulate the formation of policy preferences under full information, party cues provide effective heuristics. Although the effect of party cuing has been robustly established in US-centered studies, the literature indicates that the characteristics of modern US politics, such as political polarization, magnify the effect of party cues. Therefore, the effect of party cues has been subject to only lenient empirical scrutiny, as empirical evidence exists primarily for the US. The present study aims to test the generalizability of the effect of party cues by focusing on Japan, where the ideological positions of parties have become increasingly vague. Furthermore, in light of the fact that the media system in Japan is more stable and ideologically polarized than its party system, we also test whether press cues (i.e. newspaper names) serve as substitutes for party cues. A survey experiment demonstrates that the effects of party and press cues in Japan are muted, and therefore these two types of cues do not serve as effective shortcuts in forming policy preferences. These results indicate that issue voting based on cognitive heuristics is difficult under an unstable multiparty system. Therefore, the extant literature on party cues that presupposes the US-style party system cannot be easily generalized to other political contexts.

This study examined the freedom to talk about politics by focusing two research questions: (1) How freely Japanese citizens talk about political topics? (2) What factors increase the freedom to talk about political topics? To examine these issues, we conducted Web-based survey to collect discussion network data. The result shows that national government matters relatively scored least free, while respondents felt very-to-somewhat free to talk about political topics. In addition, political knowledge significantly increases the freedom to talk about political subject. However, newspaper use is significantly decreases it. These findings challenge assertions that Japanese citizens talk about political topics guardedly.本研究は、政治的な話題を話すことの抵抗感について検討した。具体的には、日頃話していると想定される9つの話題の中から、より政治的関連性が強い話題を話すことにどの程度抵抗を感じるのか、またその抵抗感を低減する要因も併せて検討した。20代から60代の有権者300名を対象にWeb上で、調査を行ったところ、日常的に話している9つの話題の中では、「国や政府に関する話題」が相対的に最も話すことに抵抗を感じる話題であった。しかし、実際には「国や政府に関する話題」を話す際に感じる抵抗の程度は非常に低いことが示された。また、抵抗感を低減する要因として、ハードな争点的知識が効果を持つ一方で、新聞閲読頻度が抵抗感を高めていることが明らかとなった。