Events are able to trigger our remembers and make us go deeper in our memories. When the event affects a group of people, we can say that it makes us go deeper in our collective memory. Collective memory is defined as the common representation of the past created by a group of people, this means that collective memory modulates our identity as a society. So, if something or someone is able to modify collective memory, there is a probability to change our conception of the past. Therefore, quantify the impact of events in collective memory help us to understand how beliefs, customs, and identities change over time. Certainly, one of the most important events, which affects individuals and groups of people, is death. Death is the beginning of the forgetting, but also is a memory trigger at the individual and group level, and certainly affects the behavior of people, but we don't know how much, for how long, nor in what sense.
For decades, the scholars who have studied collective memory, historical memory, popular memory, or cultural memory, have explored how populations remember historical events. The empirical side of this literature has focused on identifying the functional forms describing how ideas, events, and people are forgotten at both the individual and group--collective-- scales. However, the mechanisms that trigger remembering have got little attention.Two remarkable works are related with how airplanes crash trigger remembers of other events and how technological shocks shape what society remembers.
In order to understand how exogenous shocks, like death, impact memorability by remembering, we use a data-set of biographies from Wikipedia for all individuals who have more than 15 different language editions. Here, we focus on different external shocks that are able to trigger remembering, such as Death, Nobel Prize, Academy Awards (Oscars), Ballon d'Or, Golden Globes, and Grammy's. All of these events show an exogenous-critical non-trivial heard behavior, as described by Crane and Sornette 2008.
Figure A shows the daily pageviews received by five celebrities. To make the scales comparable, Figure B presents the number of page views minus their initial popularity, normalized by the peak popularity experienced at the moment of death, this is the normalized popularity. After this normalization, all curves collapse into a similar behavior with a characteristic exponent (Fig. B), PV=t^-b+c, where b is the characteristic exponent and c is a plateau level of popularity after death.
For all date, we find that at the moment of death, people experience a peak in the number of page views received, which is linearly proportional to their pre-death attention, followed by a power-law decay with an exponent of around -1.35 (Fig. E and F).
Moreover, we study whether the attention received by these biographies, at the long-term (parameter c) is larger than the attention they received prior to their death. For ~70% of these biographies, we find a positive and significant "attention premium,'' which grows sub-linearly with biography's pre-death popularity (as y=ax^b with b=0.87), meaning that the premium is relatively larger for less popular biographies prior to their death. Besides, the other ~30% of these biographies show a negative attention premium, this is telling us that there are changes in the collective memory in both directions. Finally, we compare attention dynamics of death and other different events, such as Nobel Price, Ballon d'Or, Golden Globe, Oscar's, and Grammy's (Fig G), and we find several differences, the most important is (with exception of Nobel Price) they don't have a significant impact on the long-term popularity.
These findings add to the growing body of literature studying the dynamics of forgetting and collective memory, and they show that collective forgetting can be described using simple mathematical functions. Furthermore, understanding the dynamics of forgetting of cultural productions and cultural icons, can help us understand success in those domains where it can be equated to reach.
Future work will be focused on how a burst of events affect memorability and the creation of cultural icons, it means people who are able to overcome the time barrier and prevalence in our collective memory.