Over the past twenty years, linguists have taken a renewed interest in the data that underlies grammatical theories. In this chapter we review five types of data: corpus data, acceptability judgments, reading times, electrophysiological data (EEG/MEG), and hemodynamic data (specifically fMRI). The approach we take for each is slightly different, as each data type occupies a different role in grammatical theory construction. For corpus data, we defer to chapter 4 (this volume) for a detailed review, and instead focus on the reasons why some linguists prefer experimental data over (observational) corpus data. For acceptability judgments, we review theirrole in theory construction because they currently form the vast majority of data used for the construction of grammatical theories. For reading time data, we review the logic that has been used to search for consequences of grammatical theories in real time sentence processing. For electrophysiological data, we observe that there is relatively little connection between the electrophysiological literature and the grammatical literature, and therefore review the basic results from the ERP literature as a first step toward encouraging closer ties between the two fields. For hemodynamic responses, we review the research into two brain areas that have been argued to be implicated in syntactic processing (left inferior frontal gyrus and left anteriortemporal lobe), as this seems like the best starting place for exploring the relationship between grammatical theories and neurobiology. In the end, it is our hope that this chapter will serve as a useful starting point for thinking about the use of data in grammatical theories for both linguistsand non-linguists.
