Most of us are familiar with the frustration of forgetting — whether it’s struggling with a word on the tip of the tongue, misplacing important items such as keys or glasses, or even disremembering why you came into a room.How can we do anything but forget — especially in a time in which we are subjected to a firehose of information every waking minute, between our life in the physical world and what comes at us electronically via smartphones, TVs, computers and more?The average American is exposed to an estimated 34 gigabytes — or 11.8 hours’ worth — of information every day, Charan Ranganath wrote in his most recent book, “Why We Remember: Unlocking Memory’s Power to Hold on to What Matters.” That figure came from a 2009 report by the Global Information Industry Center at the University of California, San Diego.”Last time I looked it up, the estimate increased …