It's absolutely atrocious logic since B is in no way implied from A. For instance to show this then you would need to, at the minimum, put the people that all individually do the best at e.g. writing a shopping list, into a group, and then compare them against people that individually do worse but score well on the [again literally] 'Reading the Eyes in the Mind' test that was used to measure 'emotional intelligence'. Of course that was not done, and I don't think it's unreasonable to speculate because we know what the result would be - and that's not publishable. Yet bad science paired with an astounding headline and you are suddenly good to go.
Yeah, a bit of a rant but it's incredibly disappointing how awful the social sciences have become. And that decline pairs ironically with a massive increase in the reporting of their results, which become ever more grand and increasingly clickbaity, in the media.
If the differences are significant, they'll appear with as few as 35 people, carefully selected, and give you a confidence level of X that it applies to a population size of Y.
Whilst I don't know the details of this particular study, I do recall doing homework problems about correlation confidence.
In layman's terms, maybe this example will help:
Imagine a study where they found that 100% of people who were "sitting" had bent knees. Essentially no one could bring their hips and ankles closer together without bending their knees. With such a significant correlation, you could generalize from a population of 10 to one of trillions so long as the ten was randomly chosen, and there were no other correlative factors.
If you take a sample of 35 people in China you can with a reasonable confidence level say all people are Chinese, or perhaps a very small proportion aren't, depends how lucky you get. It's wrong of course, despite Chinese being the majority (17% according to Wikipedia).
It's fine as a preliminary, but it doesn't show anything useful yet other than the need to perform further study IMO.
A report on this should say something like "viability study suggests sitting and brain changes are related but doesn't provide enough confidence as yet". Which it sorta does, from this section on:
>"This study does not prove that too much sitting causes thinner brain structures, but instead that more hours spent sitting are associated with thinner regions, researchers said."
But either ScienceDaily or UCLA have not lead with that information, matching the current style.
How about using a set of long haul truckers? In a before vs after sort of why? Their hours behind the wheel is documented (or should be). I would presume they're sitting behind the wheel :)