What is the fine-grained topic of the following text: The day was a great success from the very first presentation by Ben Holliday who talked about his experience as the Head of UX for the government’s department for work and pensions to the keynote speaker Peter Morville President of Semantic Studios who’s inspiring and insightful talk on ‘The Architecture of Understanding’ transcended the world of web usability and delved into the philosophy and science of human nature and behaviour. Only return the topic.
Web usability and human behavior understanding in UX design presentations