How do people choose a name for their child? Researchers have long noted that the overall popularity of a name exerts a strong influence on people's preferences—more popular names, such as Robert or Susan, are more frequent and, by their sheer ubiquity, drive more parents to adopt a similar choice.

However, new research by psychologists at New York University and Indiana University, Bloomington suggests that the change in popularity of a name over time increasingly influences naming decisions in the United States. Like momentum traders in the stock market, parents today appear to favor names that have recently risen in popularity relative to names that are on the decline.

The research, which is relevant to understanding how people's everyday decisions are influenced by aggregate cultural processes, was conducted by Todd Gureckis, an assistant professor of psychology at NYU, and Robert Goldstone, a professor of psychological and brain sciences at Indiana University. It appears in the journal Topics in Cognitive Science.

"Our results give support to the idea that individual naming choices are in a large part determined by the social environment that expecting parents experience," the authors wrote. "Like the stock market, cycles of boom and bust appear arise out of the interactions of a large set of agents who are continually influencing one another."

The NYU and Indiana researchers also note this pattern is a relatively new phenomenon. In the late 19th and early 20th century, the popularity of a name from one year to the next was correlated with a decrease in future popularity. The changing pattern, the authors suggest, arises from biases in how people estimate the overall desirability of cultural tokens like names. That is, tokens that are recently outpacing their long-term popularity are seen as better choices than those that appear to be falling out of favor.

The findings were based on a historical record of the frequency that particular names were given to babies over the last 127 years in the United States provided by the U.S. Social Security Administration.

Existing accounts of cultural evolution suggest that it is primarily the frequency of the token (i.e., name) in a parent's social environment that should drive aggregate patterns of name choice. However, by sorting through names and watching the way they rise and fall in popularity over time, the authors noted that many names appear to take surprisingly smooth trajectories through time such that increasing popularity one year is often associated with increasing popularity the next. Moreover, this trend has become more pronounced over the years.

In order to better quantify this effect, the authors analyzed the probability that a name goes up or down from one year to the next, given that it went up or down in the time period before. They found that around the turn of the last century (1880 to 1905) names tended to fluctuate in overall frequency from one year to the next. A name that increased its relative frequency one year was more likely to decrease rather than increase in frequency the following year. Similarly, decreases in frequency were more likely to be followed by increases than further decreases. However, more recently (1981 to 2006), names moved in consistent ways such that a change in popularity in one year was predictive of the same direction of change the following year. Thus, names appear to carry with them a "momentum" that tends to push changes in popularity in the same direction year after year.

"Parents in the United States are increasingly sensitive to the change in frequency of a name in recent time, such that names that are gaining in popularity are seen as more desirable than those that have fallen in popularity in the recent past," the authors noted. "This bias then becomes a self-fulfilling prophecy: names that are falling continue to fall while names on the rise reach new heights of popularity, in turn influencing a new generation of parents."

In the paper, the authors develop and test a number of formal models of cultural evolution in order to quantify the sources of bias that influence people's naming decisions. In particular, the authors incorporated well-known aspects of cognitive processing, including the way that novelty and familiarity bias our preferences. The authors found that a model that assumes that names which are outpacing their long-term popularity are preferentially selected better explains the distribution of names over time than do models which leave out this assumption.

The researchers argue that baby names provide a unique opportunity for studying the intersection of individual and group decision making for the following reasons:

It's an important decision upon which parents devote significant time and energy; There are extensive historical records, making possible the detailed measurement of these choices and the social context in which those decisions were made; Certain names (e.g., "Joshua", a popular name in 2007) do not appear to carry more intrinsic economic value than other names (e.g., "Damarion," an uncommon boys name the same year); and, Baby names are not subject to the forces of marketing or advertising—factors that may complicate the analysis of other type of culturally-relevant decisions such as fashion or music preferences.

The work was supported by grants from the National Institute of Mental Health, which is part of the National Institutes of Health, and the National Science Foundation.