Walk this way, Talk this way. Motor skills, spatial exploration, and the development of spatial cognition and language

According to the ecological embodied cognition approach, cognition and language develop through real-time body-environment interactions. These ongoing interactions, in which children explore the environment, are the basis for the development of cognition and language. The attainment of motor milestones is thought to play an important role in this process as it fundamentally changes children’s interactions with their environment. Therefore, the main hypothesis was that attainment of motor milestones propels the development of cognition and language, and that children’s exploration of objects and space mediates this relation. We focused on two central motor milestones and on two forms of exploration which were hypothesized to be intrinsically related. Unsupported sitting and independent walking were thought to be related to, respectively, exploration of spatial-relational object properties such as containment, and exploration of the larger space through self-locomotion. These forms of spatial exploration were hypothesized to be especially important for spatial cognition and spatial language, and particularly the acquisition of locative prepositions and verbs containing a direction. This dissertation contains four studies. The first study revealed, using longitudinal data from 51children, that more engagement in spatial exploration during infancy predicted better spatial memory at ages four and six years. Although, earlier attainment of self-locomotion milestone did not directly predict spatial memory, it was related to more spatial exploration during infancy, and thus indirectly predicted spatial memory. The other studies were based on data from 62 children belonging to two age cohorts, who were followed from age 9 months to 36 months. The second study, employing latent growth modelling, showed that attaining the ability to sit independently at an earlier age predicted a higher general level of productive vocabulary between ages 16 and 28 months. Early attainment of independent walking predicted a larger growth in productive vocabulary in this age range. The third study showed that between ages 9 and 36 months, the development of spatial-relational object exploration follows an overlapping waves pattern. Exploration progresses from exploring mainly single objects to exploring multiple objects and finally to exploring using combinations of objects. Over time the more complex forms of exploration are more frequently observed while the frequency of the simpler forms decreases, but the simpler forms are still observed also later in development. The fourth study revealed that attaining sitting at an earlier age predicted better spatial memory at age 24 months and better spatial language at age 36 months. Spatial-relational object exploration at age 20 months, however, did not mediate these effects. Furthermore, an earlier age of walking predicted better spatial processing at age 32 months and better spatial language at age 36 months and, as expected, exploration through self-locomotion mediated these effects. The results provide support for the hypotheses stemming from embodied cognition theory. However, the relation between motor development, exploration and cognitive-linguistic development is complex and depends on many factors such as the time-scale on which the effects are measured and the particular milestones, exploration and the cognitive-linguistic skills concerned. Practical implications and directions for future research are also discussed