In both domains of language and action understanding, the processing of nested structures (NEST) plays a crucial role. The current project aims at examining whether the processing of NEST has the same developmental trajectory in both domains and is supported by the same psychological mechanisms. Assuming this is the case, it suggests a fundamental relation between language and action processing early in development. To explore this issue, a number of empirical studies will be conducted with three- to six-year-old children.

In a first study, we will employ a correlational approach to assess developmental changes as well as interrelations between the understanding of NEST in both domains by means of a cross-sectional design. The study will obtain behavioral and eye-tracking results and will help to decide on the final stimulus set and age range to be used for all subsequent studies.

A second part of the project will examine the brain correlates of NEST understanding by means of a magnetic resonance imaging (MRI) study. Structural as well as functional gray and white matter correlates will be examined. In addition to whole-brain analyses, region-of-interest analyses focusing on brain areas known to subserve the understanding of NEST such as the temporo-parietal junction and the inferior frontal gyrus will be conducted. The brain data will be co-varied with behavioral data following the method from the first study.

Next, we will conduct a training study, exploring potential cross-domain effects of training NEST understanding in action and language. The training itself will be accompanied with pre-, post-, and follow-up behavioral and structural MRI examinations. Finally, we will employ electrophysiological assessments to investigate the neurocognitive mechanisms supporting the processing of NEST understanding in both domains. In sum, this project will inform us on whether or not the same neurocognitive processes subserve the development of NEST understanding in language and action. The contribution will present and discuss first results.