This is not technically correct. We do not derive happiness from the attainment of things.
And are those ‘things’ generally external or internally derived? We generally obtain happiness/please from ‘commodities’…stuff. The pleasure of the company of friends/family aren’t commodities, but they are external.
We are a goal or aim driven species.
All animals are and that goal is food and sex.
The dopamine system is triggered buy the sense of progress moving toward a goal. The highest dopamine hit comes before the attainment not after.
No disagreement there, but again are those aims internally-or externally derived. The point of meditative awakening is the happiness is somehow generated internally and endless while the state lasts, because it isn’t relying on stuff!
Also I don't know what type of meditation you do, but at least for Rinzai Zen, that I know, happiness is not the goal. It's pretty much inconsequential. It's a distraction.
‘Mushotoku’...ones practise should be without a goal, but didn’t you say earlier we’re a ’aim driven [sic] species’. Isn’t that a contradiction? I think mushotoku suggested not pushing things too hard as that makes the effects elusive.
Well this is my story and I'm sticking with it. Can you explain your dichotomainia. I can find nothing Google wise with a quick search. That aside, I fully acknowledge that both hemispheres are needed. That's not what I mean. I'll would have to give an indepth answer to explain.
Dichotomania was the 90s idea that one hemisphere of the brain could be preferentially selected and activated to produce preferred characteristics in the individual. It was believed the left hemisphere was analytical/mathematical/logical and the right side was creative and artistic so the belief was the right hemisphere could be activated to make you creative or the left side, to make you more Mr Spock!

This is a problematic misrepresentation.
The left side of the brain is indeed analytical/mathematical/logical dealing with minute specifics and is the dominant hemisphere, the boss in the head, but the right hemisphere looks at generalities (this in itself is a generality!). Say you were in the Louvre looking at the Mona Lisa. Your right brain may be noting the over all brown tinge to the painting, the blending of colours into each other, her face shape and hair etc….the overall image. The left hemisphere on the other hand notes the brownish tinge is due to discoloured varnish and the colour blend is ‘sfumato‘ and notes is a technique said to be pioneered by Da Vinci. It notices the uneven background the left being inexplicably, slightly higher than the right. It notes the weird lack of eyebrows of Lisa Gherardini and subtle veil edge on the upper part of her brow. All these data are
shared between the hemispheres (via the corpus callosum) to give you a coherent comprehension of the whole piece of art. It is vital they are shared and cannot be kept separate (unless you’ve had a surgical commissurotomy) otherwise we’d have incomplete comprehension. Suppressing one hemisphere would be like trying to prevent alternate combustion chamber valves in a car engine from functioning. That simply can’t happen as they’re on the same crankshaft.
It is this ‘detail/generalities’ information processing that allows us to make sense of the world.
What meditation/psilocybin seems to do is disrupt or even cease the communication between processing modules of the brain whether they be contra- or unilateral.
Does this help?