Head external analysis, head raising analysis or matching analysis? Let's ask experimental syntax

• The Head Raising Analysis is proposed for Basque relative clauses.
• The data obtained through four experiments in which 32 Basque native speakers participated supports the Head Raising Analysis.
• Basque always uses the head raising strategy to construct relative clauses regardless of the type of gap.

This paper aims to discover the structure of relative clauses in Basque. Three conflicting analyses have been proposed for Basque RCs: the Head External Analysis (Oyharçabal, 1988, Artiagoitia, 1992 and Rebuschi, 2003), the Head Raising Analysis (Vicente, 2002) and the Matching Analysis (de Rijk, 1972). The results of the experimental data collection confirm that Basque follows the head raising strategy to build RCs with an ergative or absolutive gap. These data were obtained through four experiments in which 32 Basque native speakers (16 male/16 female) participated. The first test is a grammaticality judgment task to test island-sensitivity. The second one is an interpretation task to test idiom interpretation. The third and fourth are an associated pictures match task to test scope interaction and interpretation of adjectival modifiers respectively. Additionally, native speaker introspection and grammaticality judgment under direct elicitation show that Basque also uses the head raising strategy to construct RCs with a dative or inessive gap.