In a new study, Americans disproportionately chose the years of their own youth as the country’s greatest years – no matter how old they were now. This finding is the latest involving a phenomenon known as the reminiscence bump.

https://www.theguardian.com/science/head-quarters/2017/oct/31/the-reminiscence-bump-why-americas-greatest-year-was-probably-when-you-were-young

Reminiscence bump. Also reference to declinism: is the world getting worse.
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