The ability of humans to accumulate knowledge and information across generations is a defining feature of our species. This ability depends on factors that range from the psychological biases that predispose us to learn from skillful, accomplished, and prestigious people, to the development of technologies for recording and communicating information: from clay tablets to the Internet. In this paper we present empirical evidence documenting how communication technologies have shaped human collective memory. We show that changes in communication technologies, including the introduction of printing and the maturity of shorter forms of printed media, such as newspapers, journals, and pamphlets, were accompanied by sharp changes (or breaks) in the per-capita number of memorable biographies from a time period that are present in current online and offline sources. Moreover, we find that changes in technology, such as the introduction of printing, film, radio, and television, coincide with sharp shifts in the occupations of the individuals present in these biographical records. These two empirical facts provide evidence in support of theories arguing that human collective memory is shaped by the technologies we use to record and communicate information.