According to the author, human memory is unreliable because people

Developments in electronic science have transformed the art of record keeping to the modern age. Traditionally, records of events were kept only in people’s minds. It depends very much on the retentive power of the human memory. This was extremely dangerous as people either forgot events wholly or in part or deliberately falsified details to suit their various interests. Interminable arguments were thus order of the day. Even writing which replaced mental recording was not entirely free from these shortcomings as untruths could be written as true either willingly or inadvertently. With the advent of the electronic memory, however these dangers have been largely overcome. Recording on audio and video cassettes now show not what happened, but also who did or said what including how and when