Neuronal connections are bi-directional ("Neurons that fire together wire together"), so if you want to experience happiness, focus on feeling sensation all over the body just like the emotions maps.
A really easy (though not necessarily fun) one to try is disgust. Right now, just focus on the sensations in your neck. If you have any body awareness you should feel some yuckiness there. If you are unable to feel it, you may be a habitually hyper head-oriented person and may be totally disconnected from your emotional body. If this the case, I highly recommend learning to meditate to fix the issue.
For larger body sensations like happiness, just focusing your attention may not be enough though since your concentration may not be high enough and will naturally flit around. So in addition to focusing attention, move those parts of the body to generate sensation.
This also happens to be the basis for traditional teachings and methods along these lines.
Also: while emotions largely follow the average, individuals have specific variations that I think relate to habits or hangups accrued from living. In the meditative world, these bodily sensations that give variations from the basic emotions are called obscurations. If you focus your awareness on parts of it, then you can see memories and thoughts associated with that particular obscuration (as it arises from the body).
Even cooler is when you watch it long enough, you start seeing how the whole pattern/set of these different body sensations change in a predictable pattern, sometimes even "triggering" another set of patterns.
Finally, these very sensations also makes it difficult for people to "let go", like during meditation, or when things are going well. The mind is habituated to feeling these patterns of sensations, and when they don't happen, you literally start feeling like a different person ... and for many folks, that is frightening.
It's really really weird to be blissed out one second and experiencing existential fear the next, but that's what happens.
I guess non-mainstream methodologies/frameworks like NLP, chakras and yoga were on to something when they said that emotions have locations in the body.
There's one bit about the happiness: it might be mostly in one's head, but it covers the whole body. Happiness is related to contentedness, that feeling that you don't need to go anywhere and you're good right here. If happiness did not cover a part of the body, then usually, that part will start agitating for attention. You are no longer content.
The warm-dark color scales have a slight emphasis on the warmer colors though. They are not exactly of same lightness.