The name-letter effect is the tendency of people to prefer the letters in their name over other letters in the alphabet. Whether subjects are asked to rank all letters of the alphabet, rate each of the letters, choose the letter they prefer out of a set of two, or pick a small set of letters they most prefer, on average people consistently like the letters in their own name the most. Crucially, subjects are not aware that they are choosing letters from their name.
Discovered in 1985 by the Belgian psychologist Jozef Nuttin, the name-letter effect has been replicated in dozens of studies, involving subjects from over 15 countries, using four different alphabets. It holds across age and gender. People who changed their names many years ago tend to prefer the letters of both their current and original names over non-name letters. The effect is most prominent for initials, but even when initials are excluded, the remaining letters of both given and family names still tend to be preferred over non-name letters.
Most people like themselves; the name is associated with the self, and hence the letters of the name are preferred, despite the fact that they appear in many other words. People who do not like themselves tend not to exhibit the name-letter effect. A similar effect has been found for numbers related to birthdays: people tend to prefer the number signifying the day of the month on which they were born. Alternative explanations for the name-letter effect, such as frequent exposure and early mastery, have been ruled out. In psychological assessments, the Name Letter Preference Task is widely used to estimate implicit self-esteem.
There is some evidence that the effect has implications for real-life decisions. In the lab, people disproportionately favor brands matching their initials. An analysis of a large database of charity donations revealed that a disproportionately large number of people donate to disaster relief following hurricanes with names sharing their initial letter (e.g. Kate and Kevin following Hurricane Katrina). Studies that investigate the impact of name-letter matching on bigger life decisions (where to live, whom to marry, which occupation to take on) are controversial.