*3.1. Materials*

The stimuli used were a set of 12 videos compiled by the Max Planck Institute for Psycholinguistics created in order to elicit ditransitive constructions with actions such as GIVE and TAKE. All the videos include three people (two women and one man or two men and one woman) who are transferring an object to one another. In most videos, only two of the three persons are conducting the action, the last one remaining still. The arrangemen<sup>t</sup> of the three persons varies in each video. Various types of objects are being passed around: a bulb, a flower, a book, etc., see Figure 1.

**Figure 1.** Stills of some of the video stimuli used in the task.

Verbs such as GIVE and TAKE were especially relevant as they can be used in ditransitive constructions, that is, with three arguments: an agent, a patient and an object being transferred. These stimuli are particularly relevant to examine whether signers are able to use the signing space to express verb agreement. In fact, these specific stimuli, or similar versions of them, have been employed in studies run in many sign languages all over the world in order to address the same question (see among others Meir et al. (2007) and Padden et al. (2009) for ABSL, Senghas (2003) and Gagne (2017) for NSL) and allow for a cross-cultural comparison of how agreemen<sup>t</sup> is expressed in these different languages.
