Perception: How we interpret to make sense to us. Depending on how we feel is how we interpret things, for example, when looking at something that has 'hidden' images in (see below) you may choose to see something that is otherwise not there to other people, all depending on what we feel at the current moment and actually want to see.
The lecture also looked at a BBC Four documentary which explored senses, particularly in the documentary there was a 48 hour expeirment where people were placed inside a bunker with no noise (showing an example of how we rely on sound) Eventually into the experiment a lot of the personnell involved starting visualizing things or creating their own noise, forcing a lot of anxiety between them and the situation.
Every sense is essential to our development, we, as designers, have to look more into the emotional responses that our designs would influence someone into thinking a certain way, and not just from a design sake. Although the lecture, to me, wasn't very benefical, I can see why we need to look more in-depth at why stuff is presented in different ways.