I would also like to thank Natasha Kwok for helping me record, select, and cut the video files that make up the final set. A big thank you goes to Lukasz Walasek and Neil Stewart for helping me run my norming experiments in a web-based environment. And, of course, the development of this database would not be possible without the adult participants who took part in the norming experiments. Furthermore, I would like to thank the nurseries, parents, caregivers, and children who took part in the memory and verb learning experiments reported in this dissertation. Without them, this research would not be possible. I am really grateful that the children were so sweet, excited, helpful, patient, and attentive during the tasks. I would also like to express my sincere gratitude to my first supervisor, Professor Sotaro Kita, for his excellent advice on study ideas, scientific articles, grant proposals, and strategic career choices. It was a great pleasure to brainstorm about research ideas. We have probably come up with more ideas than we could possibly investigate in the next three years (without any help). It was also a very useful experience for me to write articles together. I feel that Kita has prepared me for the academic world in the best possible way. We have been very productive over the last three years, and I hope to continue our fruitful collaboration in the years to come. I would also like to thank my second supervisor, Dr Katherine Messenger, for her invaluable advice on the practicalities of developmental research. Kate's comments on my Early Career Fellowship grant proposal were very useful. viii This thesis is submitted to the University of Warwick in support of the application for the degree of Doctor of Philosophy. It has been composed by the author and has not been submitted in any previous application for any degree. The work presented (including data collection and data analyses) was carried out by the author.