You Name It – How Memory and Delay Govern First Name Dynamics

The adoption and abandonment of first names through time is a fascinating phenomenon that may shed light on social dynamics and the forces that determine cultural taste in general. Here we show that baby name dynamics is governed almost solely by deterministic forces, even though the emerging abundance statistics resembles the one obtained from a pure drift model. Exogenous events are shown to affect the name dynamics very rarely, and most of the year-to-year fluctuations around the deterministic trend may be attributed solely to demographic noise. We suggest that the rise and fall of a name reflect an “infection” process with delay and memory. The symmetry between adoption and abandonment speed emerges from our model without further assumptions

Frequency variations for three typical first names (a) and surnames (b) in Norway.

<p>The percentage (out of the total number of male birth during a certain year) of boys named Alf, Alfred and Arnold is plotted in the upper panel, and shows a pronounced pattern of rise and fall in popularity. Surnames like Brekke, Moe and Haugen show much weaker trends (if any, and demographic fluctuations are responsible for most of the variation.</p

Name-abundance distribution curve for boys names.

<p>The number of names with abundance (frequency, in percent) <i>s</i> is plotted against <i>s</i> on a loglog scale (red circles), and shows a very good fit to the distribution suggested in Eq. 1 (blue line).</p

Quantifying stochasticity: the deterministic part of the dynamics was extracted from the timeseries associated with a given name using MATLAB’s smoothing algorithm, as shown in panel (a) for the first name in the girls’ list, Aagot.

<p>The distance from the real data (point) to the “prediction” of the deterministic dynamics (line), was then extracted for any year at each time series. After appropriate normalization for demographic noise [Eq. (2)] a histogram for the log of the deviations is shown in panel (b). The distribution of Z falls, more or less, exponentially with a width which is much smaller than unity.</p

The frequency of all the boys’ first names is plotted in the right panel (a), for each name the frequency is divided by its maximal value and the timeseries were shifted such that the peak of all series appear at zero.

<p>Time for each name was normalized by the width of the peak τ, which is defined as the minimal number of years that takes for the name to fall to 10% of its peak value. The bell shape showing the process of rise and decline, and the “wings” showing reentrance of some names, are clearly seen. None of these is seen for surnames (b) when their abundance is plotted using the same procedure.</p

Overpopularity: The names Anna (for girl) and Ole (boy) were extremely popular at the end of the 19^th century, high above the level that prevents modern parents from using the name.

<p>The result was a sharp decline of these names frequency until they both reach the level of 1–2 percent, which is similar to the frequency of the most popular names nowadays.</p

(Rare) examples of a pronounced exogenous factor that affects first name dynamics.

<p>Panel (a) shows three girls’ time series in which large and sudden changes are manifested. The two sharp rises in the frequency of Regnhild and Astrid in 1932 and 1933 are related to the birth of the princesses that carry these names at these years, correspondingly. The birth of prince Harald on 1937 explains the sudden popularity that this name gains in that year as shown in panel (b) for boys names. Fred (peace) became popular at the end of WWII, but we have no explanation for the dramatic rise of Emma on 2003.</p