One of the TLDR: the feeling of being happy and being sad are not the same brain-function with a sign reversed. Just because you're not happy doesn't imply you are sad and vice versa, just because you're not sad doesn't imply you're happy.
You have to train not-being-sad and being-happy independently!
 every hypothesis was experimentally tested!
56 Up was the first one I had seen. And it really does give you a sense of mortality and how quick life's years can go by, in a blur of routine.
There are 29.453.760 minutes in 56 years. There were 14 people, for a total of 412.352.640 minutes of lifetime.
That a speed up factor of 536.219. It seems like any biological system sped up 500k times it's normal rate is going to give a sense of mortality.
Reminds me of a guy who shot 1 second every day for a year to make a video. He ended up on Ted's main stage and ended up making an app.
Edit: link more directly to data access page.
Subtle British humour. The article is full of stuff like this. Just trying to help those who don't get it, or don't understand where the "happy" is found from the title.
Human sciences lack of a shared model (like in physics). Most studies remain separated and become dead branches. It's a bit sad.
I have a hard time believing this is much different in Psychology compared to other disciplines. What are you basing this on?
I know they use different models. Some models can be common across multiple disciplines (like psychology and sociology).
Biology is probably the smallest denominator.