The global #MeToo movement got us thinking about something no one’s covering: the wives who are faced with a public display of their husbands’ behavior, and yet turn a blind eye. From Bill Cosby to Jerry Sandusky to Bill Clinton, plenty of men have been accused of impropriety — or criminal behavior — and had their wives stand with them in solidarity. Is it folly, true love, or a little of both?

New research from City, University of London, University of Oxford and Yale University sheds some light on our uncanny human ability to see people we love through rose-tinted glasses. The research, published in the journal Psychological Science, showed that optimism bias — our tendency to overestimate the probability of positive events — extends to our partners and people we love.

Dr Andreas Kappes, lead author of the study and a lecturer in the Department of Psychology at City, University of London, said: “Our research shows that we see not only our own lives through rose-tinted glasses, but also the lives of those we care about.”

The study, which is the first to show that such an optimism bias extends beyond the self, found that people readily changed their beliefs about a person they like when receiving good news, but barely changed their opinions about them after receiving bad news. This “vicarious optimism” in their learning about others was found to be stronger the more people cared about another person.

Faced with difficult circumstances in a marriage, one might imagine how optimism bias plays out: bad news or evidence of a negative occurrence might change a partner’s belief system very little, whereas hearing something positive about the partner would register. This learning bias may stem from a sort of emotional self-preservation instinct and a need to view our life situations or futures as inherently positive.

This is likely one more way that our minds help us to avoid cognitive dissonance, the psychological term for not wanting to accept when things don’t square with our existing worldview. As a human psychological tendency, optimism bias helps to shield us from information that dismantles our carefully constructed view of our personal reality.

These tricks our minds play on us, to enable us to adapt and thrive in a world rife with contradictions and painful realities, further extends to something called confirmation bias. This is the tendency to seek out and believe information that confirms your existing thoughts and beliefs, while disregarding or discrediting the information that is inconsistent with these beliefs. Another new study, recently published in Health Promotion Practice, for example, found that over 50% of parents didn’t believe their children’s Body Mass Index scorecards — an objective measure of physical health. In fact, only 13% of the parents of “at risk” children said they would make changes to their child’s diet or lifestyle. This example is particularly poignant because it suggests that even when we’re being given information that might positively impact a loved one, we may disregard it if it forces us to acknowledge an unpleasant or negative fact about that loved one.

The human brain seems hardwired to help us absolve our loved ones of their personal flaws. (Incidentally, people also harbor positive partner illusions, the tendency to see romantic partners as more physically attractive than they objectively are.) What happens when someone doesn’t like their spouse, well, that might be a new avenue for some follow-up research.