The present study investigated the effects of framing the European Union (EU) as a common project vs. a common heritage on participants' attitude towards EU integration (Experiment 1) and EU enlargement (Experiment 2). An additional aim was exploring whether the different frames affected the strength of identification with the EU, and if the framing effect on attitudes was mediated by participants' identification with the EU and/or by their message evaluation (Experiment 3). Results showed that a common project-based frame was more effective than a common heritage-based frame in promoting positive attitude toward EU integration and enlargement, as well as participants' identification with the EU, which mediated the framing effect on both attitudes; the mediation of participants' message evaluation was not significant. The procedure of the last experiment was replicated on a British sample (Experiment 4), showing a similar pattern of results.
Keywords: EU enlargement; EU integration; European identity; common heritage; common project.