PARIS — Quick question for urban citizens who own a car: How do you remember where you parked you car the night before? You could memorize the street name and number, which is not very modern (prehistoric man already used his "internal" memory); you could take out a pen and write the address down, though that is so old media (writing and papyrus were invented more than 5,000 years ago); or you could take a picture of the parking spot with your smartphone. Not bad.

But you can get even trendier: downloading an app like Tuture that automatically remembers where your car is.

The deeper question is: How far will the externalization of our memory go? The human being has always used his creativity to devise solutions to save him effort. We have constantly subcontracted a part of the effort of our organs, like muscular work, to others (prisoners, slaves ... ), animals (horses, donkeys ... ) and then to tools or machines.

Memory did not escape this longstanding practice. "We're living the third act of the externalization of memory," declares Michel Serres. "First there was, in Mesopotamia in about 3,500 BC, the transition from oral to written communication, that allowed humans to transpose memory into codes, written words, on an external object, shelves, papyrus scrolls. Then, there was the invention of printing in the 15^th century in Europe."

For this philosopher and historian of science, with the digital age we are again living through an extraordinary change on this front. "Writings, sounds, images — Digital technology can save almost everything and spread it very quickly: Half of humanity now has a cellphone."

Memory prostheses

Necessary memorization efforts to acquire and transmit knowledge have been drastically reduced. In the distant past, instructors, those from the oral tradition, had to learn everything by heart; their successors, those from the written tradition, were required only to remember where and how to find a book about any given topic. This effort is now unnecessary. "Today, the access to information is much better than the two previous revolutions: You only need to type some keywords in a search engine," adds Serres.

This all makes it tempting to entrust everything to these "memory prostheses." A study conducted on 6,000 Europeans a few months ago by Kaspersky Lab, specialized in cyber security, revealed that 43% of the respondents between 16 and 24 years old, believe their smartphone contains practically everything they need to know or remember. Some experts, like Nicholas Carr, author of Does the Internet Make You Dumber? or to a lesser extent, Betsy Sparrow, from the department of psychology at New York's Columbia University, believe that youth today suffer from "digital amnesia."

This observation should be seen in relative terms. First, the experts' views should be taken with caution, simply because they feel threatened by the current revolution, they tend to denigrate it. "If the book was mostly a reading revolution, digital is a revolution that plays down the importance of writing for a large proportion of humanity," states Laurence Allard, a sociologist specialized in innovative communication practices. "So, elites, who until now were the only ones to have access to writing and knowledge, are perturbed."

Secondly, we still lack perspective regarding the phenomenon. "It's important that we think about the impact of new technologies on education and children," notes Francis Eustache, a neuropsychologist, director of a French research unit completely dedicated to the study of human memory, INSERM Unit U1077. "We would need to be able to conduct an objective study but we lack scientific data."

Critical mind

One thing is certain: If we want to remain social, keep understanding the world, stay imaginative and delay the effects of aging, we will have to be sure our memory is still functioning. "We should give children the time they need to read, learn poetry, songs ... everything that constitutes our collective memory," says Eustache. "Otherwise, our society might lose common ground."

Memory is also essential to a better personal life. "Children are capable of looking to the future when they can remember yesterday," explains Michel Desmurget, a researcher in neurosciences and research director at INSERM. "Memory is the indispensable foundation of intelligence and creativity: Without it, great minds would not have established links between two pieces of information that had never been compared before."

But in addition to intelligence, critical minds and curiosity will stay essential. If only to sort the information proposed by tomorrow's memory props (connected watches, companion robots etc.). "Google organizes knowledge according to mysterious algorithms: We have to provide our kids with judgment skills and critical thinking that's, sort of, the trademark of the French education, inherited from the Age of Enlightenment," says Catherine Becchetti-Bizot, the former director of the Ministry of National Education program, "digital for education."

Then on the other side of the life cycle is another consideration: To stem the effects of neurodegenerative diseases like Alzheimer's, researchers say it is important to stimulate the intellectual activity that calls on memory, known as "cognitive reserve."