They noted that although an rapidly increase of the the quotation rate shortly after a publication of a new scientific article, it quickly reaches its climax followed by a fall after the first year, as is said in the study. In this way newly published articles and studies disappear much faster from the scientific discourse than 40 years ago and thus fall quickly into oblivion. The amount of scientific publications has multiplied rapidly in the last 40 years.
As a study basis, the researchers used about 23 million articles from the four disciplines chemistry, physics, clinical medicine and molecular biology. Source was the Reuters Web Science database. They analyzed the periods in which new publications were cited in other articles.
Original study:
Della Briotta Paroloa, P., Kumar Pana, R., Ghoshb, R., Hubermanc, BA, Kaskia, K. & Fortunatoa, S. (2015): Attention decay in science. Cornell University Library.
http://arxiv.org/abs/1503.01881
Source (in German):
http://www.sueddeutsche.de/wissen/studie-wissenschaftler-produzieren-zu-viele-studien-1.2390512