…I CAN do better. Because Babbage is, well, better than average. More moral, trustworthy, honest, dependable, compassionate, generous, law-abiding, self-controlled and kinder to others. His children are above average too, just like every child in Lake Wobegon (from where he is writing this above-average article).

Call it the better-than-average effect, or BTAE. The fact that people consistently judge themselves superior to an average peer on most personality traits is one of the cornerstones of social and personal psychology. The extent of the effect is influenced by a number of factors (such as whether an individual is judging her strengths or weaknesses, or comparing herself to a specific rather than average peer), but numerous studies have shown the underlying BTAE to be highly consistent.

This can be a good thing. Overrating their abilities, personality traits and prospects can help people overcome obstacles, persevere at difficult tasks and feel better about themselves. It can also be a bad thing: those who are, say, lazy or selfish but underestimate the extent of these problems will not be motivated to improve.

In general, however, it has been assumed that the BTAE is self-limiting: if an individual’s claims of superiority are too outlandish, nobody will believe them—including the individual themselves. Believing that I can do a little better than my team’s average of an eight-minute mile may motivate me to improve my time. Believing that I can run twice as fast as the average is simply setting myself up for failure. Reality can only be distorted so far before it snaps.

Although the BTAE is widely cited in psychology literature, it is not usually measured against an objective standard. So whether or not people actually are better than average in terms of a particular trait cannot generally be judged unequivocally—perhaps their claim actually is rational rather than self-enhancement? A new study published in the British Journal of Social Psychology seeks to address this by demonstrating the existence of the BTAE in a group of people whose personality traits are too irrefutably negative to convincingly prove otherwise: convicted prisoners.

Researchers from the University of Southampton, the University of London’s Royal Holloway college, and Ohio University interviewed 85 prisoners at a jail in the south of England, at least two-thirds of whom had been convicted of robberies or violent crimes (some did not disclose their offence). All were asked to assess how they compared with both the average fellow prisoner and the average member of the (non-prison) community in terms of the nine traits listed above in the first paragraph.

Unsurprisingly, the prisoners rated themselves better than the average inmate on every trait: they considered themselves more moral, trustworthy, honest, dependable, compassionate, generous, law-abiding, self-controlled, and kinder to others. Remarkably, they also rated themselves better than the average member of the non-prison community on eight out of the nine traits. The exception was “law-abidingness”, where, although they did not rate themselves above average, they rated themselves as equally law-abiding—perhaps the study’s most surprising finding, given that they were behind bars.

For the researchers, the results offered evidence that the BTAE is measuring self-enhancement rather than a rational (or even partly rational) self-assessment, particularly given their findings on prisoners’ law-abidingness and honesty in comparison to the broader community (the stark difference between the two communities effectively offers an objective standard).

But the research also raises broader questions. Are prisoners in denial about their crimes, or do they minimize the severity or immorality of what they have done? Or is it simply that they are unaware of the nature of their behaviour—that they simply misunderstand the meaning of “law-abiding”? Regardless, the findings offer some insight into why previous research has shown that prisoners consistently underestimate the likelihood that they will offend again when released; in their minds, they are already law-abiding citizens despite their incarceration for precisely the opposite behaviour.

Of course, in Lake Wobegon there are none of these kinds of problems—but even if there were, they would be better-than-average problems anyway.