Homophily, the tendency of people to have ties with those who are similar, is a fundamental pattern to understand human relations. As such, the study of homophily can provide key insights into the flow of information and behaviors within political contexts. Indeed, some degree of polarization is necessary for the functioning of liberal democracies, but too much polarization can increase the adoption of extreme political positions and create democratic gridlock. The relationship between homophilous communication ties and political polarization is thus fundamental because it affects a pillar of democratic regimes: the need for public debate where divergent ideas and interests can be confronted. This research compares the degree of homophily and political polarization in Catalan MPs’ Twitter mentions network to Dutch MPs’ Twitter mentions network. Exponential random graph models were employed on a one-year sample of mentions among Dutch MPs (<em>N</em> = 7,356) and on a one-year, three-month sample of mentions among Catalan MPs (<em>N</em> = 19,507). Party polarization was measured by calculating the external–internal index of both Twitter mentions networks. Results reveal that the mentions among Catalan MPs are much more homophilous than those among the Dutch MPs. Indeed, there is a positive relationship between the degree of MPs’ homophilous communication ties and the degree of political polarization observed in each network.

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Twitter 政治网络中的同质化和极化：跨国分析

同质性，即人们与相似的人建立联系的倾向，是理解人际关系的基本模式。因此，对同质性的研究可以为政治背景下的信息流和行为提供关键见解。确实，自由民主国家的运作需要一定程度的两极分化，但过多的两极分化会增加极端政治立场的采纳，并造成民主僵局。因此，同质的沟通联系和政治两极分化之间的关系是根本性的，因为它影响到民主制度的一个支柱：需要进行公开辩论，以应对不同的想法和利益。这项研究比较了加泰罗尼亚国会议员的推特提及网络与荷兰国会议员的推特提及网络的同质性和政治两极分化程度。指数随机图模型被用于荷兰国会议员中一年的提及样本（<em>N</em> = 7,356）和加泰罗尼亚国会议员中一年三个月的提及样本（<em>N </em> = 19,507）。通过计算两个 Twitter 提及网络的外部-内部指数来衡量政党极化。结果显示，加泰罗尼亚国会议员中的提及比荷兰国会议员中的提及更多。事实上，国会议员的同质性沟通联系程度与在每个网络中观察到的政治两极分化程度之间存在正相关关系。通过计算两个 Twitter 提及网络的外部-内部指数来衡量政党极化。结果显示，加泰罗尼亚国会议员中的提及比荷兰国会议员中的提及更多。事实上，国会议员的同质性沟通联系程度与在每个网络中观察到的政治两极分化程度之间存在正相关关系。通过计算两个 Twitter 提及网络的外部-内部指数来衡量政党极化。结果显示，加泰罗尼亚国会议员中的提及比荷兰国会议员中的提及更多。事实上，国会议员的同质性沟通联系程度与在每个网络中观察到的政治两极分化程度之间存在正相关关系。