What the data actually shows
On the personal side, researchers describe a pattern often called rosy retrospection: people tend to remember past events more positively than they rated those same events while living through them. In studies that asked people about a trip or experience before, during, and afterward — work associated with Mitchell and Thompson in the 1990s — the remembered version tended to drift upward over time, smoothing out the boredom, friction, and minor miseries that were obvious in the moment.
On the societal side, researchers describe declinism: a widespread belief that the world is deteriorating and that some earlier era was a golden age. Recent work by Mastroianni and Gilbert (2023, Nature) gathered large numbers of surveys and found that people in many countries and across many decades have reported that morality and people's behaviour are declining — yet the same respondents' assessments of the people around them in the present did not track that supposed fall. The belief in moral decline appeared remarkably stable and largely independent of measurable change.
Both patterns are usually traced to ordinary cognitive tendencies: a negativity bias that makes present problems feel vivid and unpleasant memories fade faster than pleasant ones, plus the way nostalgia selectively highlights warmth and belonging. The data does not show that earlier eras were uniformly worse or better; it shows that the feeling of decline is common, persistent, and only loosely connected to the underlying facts.
Why this feels different from how it actually is
The past feels better partly because of how memory stores it. Unpleasant and mundane details tend to fade faster than emotionally warm ones, so the version you can recall years later is already pre-edited toward the good. You are not comparing the present to the past as it was — you are comparing it to a curated highlight of the past, with the dull and difficult parts quietly removed.
The present, by contrast, arrives unedited. You experience today with all its frictions, uncertainties, and unfinished business in full view, and negativity bias makes those problems louder than the comparable problems of a decade ago, which have softened or been forgotten. So the comparison is structurally unfair: a smoothed memory on one side, the raw and anxious now on the other.
Nostalgia adds a further pull. The eras people most often idealise tend to coincide with their own youth — a time of fewer responsibilities and stronger novelty — which makes 'the world was better then' hard to separate from 'I was younger and had less to worry about then.' The feeling is real; its interpretation as a fact about history is the part that usually does not hold up.
What the research says to do about it
The most useful move is simply to know the pattern exists, because rosy retrospection and declinism are easier to discount once you can name them. When you catch yourself concluding that everything used to be better, it is worth treating that as a prompt to check rather than a conclusion to trust — the feeling is common enough that it tells you very little on its own.
Where you can, replace the remembered version with a recorded one. Diaries, photos, messages, and contemporaneous notes routinely surprise people, because they preserve the boredom and frustration that memory edits out. Checking a specific claim ('was that job actually better?') against concrete records tends to deflate the sweeping version of the past.
Research on nostalgia also suggests it is not something to suppress — used deliberately, recalling fond memories can support mood, connection, and a sense of meaning. The distinction that matters is between enjoying nostalgia as a feeling and treating it as evidence. The first is generally fine; the second is where the distortion does its work.
What the research says does not help
Taking the feeling at face value — concluding that because the past feels better, it was better — is the core mistake, and it is the one the research most directly cautions against. The feeling appears reliably in good times and bad, which is precisely why it is a poor measuring instrument for whether things have genuinely declined.
Trying to argue yourself out of all nostalgia tends not to help either, and may not be desirable; the warm memories serve a real psychological function. The goal is not to stop feeling that the past was sweet, but to stop mistaking that sweetness for a balanced historical comparison.
Comparing a hazy, idealised past to a fully detailed present — the default comparison your mind offers — is structurally rigged and consistently misleads. Without recorded detail or actual data on both sides, the contest is between an edited memory and an unedited now, and the past will almost always seem to win.
Real numbers in context
The clearest large-scale evidence comes from work on perceived moral decline. Mastroianni and Gilbert (2023) drew on hundreds of surveys spanning many countries and, in places, decades, and found that the belief that morality is declining was nearly ubiquitous and strikingly stable over time — while people's ratings of the morality of those currently around them did not show the matching fall. The decline people were sure they had witnessed was not visible in their own present-day assessments.
On the personal side, the rosy-retrospection studies are smaller and the effect is a tendency rather than a universal law — not everyone idealises the past, and some experiences are remembered more harshly than they felt. The honest summary is that both biases are well-supported as common patterns, but they describe a direction memory and judgment tend to lean, not a guarantee about any single person or any specific historical claim.