Older people are more often fulfilling the above premises, and thereby the above conclusion.
This means: Worse learning performance is not a consequence of age per se.
The actual cause of this high-level change could be lower-level age-induced differences in neurotransmitter levels or in neuronal function and connectivity. As the article's summary points out, the actual biological basis needs to be investigated in further research.
It's also important to note that this study found a plausible explanation for changes in learning performance under specific circumstances. This is a very important qualification.
Learning in general is believed to involve many different interrelated mechanisms. It's well established that many different cognitive abilities (perhaps most importantly working memory) diminish with age, and some of this degradation is likely related to natural cerebral shrinkage (a healthy 75-year-old has a 15% smaller brain than a 25-year-old).
> Why do older adults fail to represent sufficient levels of uncertainty? One possibility is that representing appropriate levels of uncertainty requires a cognitive and/or biological resource that decays across healthy aging. One obvious candidate for such a resource is working memory capacity. ...
> Another possibility is that older adults fail to represent sufficient levels of uncertainty because they have an aversion to uncertainty or the mental effort required to represent it. ...
> The crucial factor limiting uncertainty representations in older adults could, and at some level must be, biological in nature. One candidate for such a limiting factor is norepinephrine ...
> Although it is tempting to link age-related changes in representing uncertainty to reduction of a single neurotransmitter, several alternative biological accounts exist. ...
1. I think I know nothing.
2. I try to learn hard to get better.
3. goto 1.