Does research on psychology and aging ever teaches us anything fundamental about psychology or is it only relevant for understanding aging?
It turns out that sometimes what we assumed were “universal” mechanisms based on research with undergraduates are processes that depend on the person being young and do not reflect anything universal. A great example of this is from two recent studies that examined age differences in emotional modulation of startle and found that older adults show the opposite pattern as younger adults, which rules out the dominant explanation in the field for how emotion modulates startle. To learn more, take a look at my commentary:
Frontiers in Aging Neuroscience
The key point is that research comparing age groups can be essential for understanding the basic mechanisms of psychological effects, not just for understanding age differences.