Full article - http://uxmag.com/articles/the-psychologists-view-of-ux-design

In a nutshell they highlight 10 things (although it really is worth reading the full article):

1. Don't make people work hard or think more than they have to

2. There's limits to what people can and want to do

3. People aren't perfect... they often make mistakes

4. People memories aren't set in stone... They will often reconstruct memories in different ways

5. People are social - sheep. They will follow by example (Social Validation)

6. We have limited attention and we're easily distracted. Make it eye catching, different and novel

7. What's going on? As humans, we need feedback. We need to feel like we know why the spinning beach ball of doom is spinning

8. Acting unconsciously - make it easy for the user to commit to a small action without conscioudly realising it and they are much more likely to follow it up with a conscious bigger action

9. Mental models - no, not wierd looking airfix planes. People have ideas of actions in their head of how something functions. Match their model, or be able to teach them a new one

10. Aesthetics - make it easy for the user. No clutter. Logical grouping. Easy to find navigation and visual feedback. Red means stop... That sort of thing.