Are smartphones harmful to human memory? Maybe, says one expert. (Richard Newstead/Getty Images)

Has our reliance on iPhones and other instant-info devices harmed our memories? Michael Kahana, a University of Pennsylvania psychology professor who studies memory, says maybe: “We don’t know what the long-lasting impact of this technology will be on our brains and our ability to recall.” Kahana, 45, who has spent the past 20 years looking at how the brain creates memories, is leading an ambitious four-year Pentagon project to build a prosthetic memory device that can be implanted into human brains to help veterans with traumatic brain injuries. He spoke by telephone with The Post about what we can do to preserve or improve memory.

Do you play any games or have any tricks to keep your own memory working?

Practicing the use of your memory is helpful. The other thing which I find helpful is sleep, which I don’t get enough of. As a general principle, skills that one continues to practice are skills that one will maintain in the face of age-related changes in cognition. [As for all those brain games available], I am not aware of any convincing data that mental exercises have a more general effect other than maintaining the skills for those exercises. I think the jury is out on that. If you practice doing crossword puzzles, you will preserve your ability to do crossword puzzles. If you practice any other cognitive skill, you will get better at that as well.

Michael Kahana once could name every student in a class of 100. Now, says the University of Pennsylvania psychology professor who studies memory, “I find it too difficult even with a class of 20.” (From Michael Kahana)

Do you have trouble remembering things?

I used to have a legendary memory for scientific articles. I could recall the authors, the journal and publication year of almost any article I had read. That capability, which was unusual for most people, I no longer have. It’s much blurrier now. Like all of us, it’s harder for me now to remember proper names. I used to teach a class of 100 students and learn almost all of their names. Now I find it too difficult even with a class of 20.

With all of the multi-tasking among devices now, do you notice a shorter attention span among your students today compared to previous generations?

I have clearly seen reliance on technology rather than memory. They immediately turn to a device to answer the question. It can be as quotidian as looking up a phone number or a name instead of trying to recall it. We don’t know what the long-lasting impact of this technology will be on our brains and our ability to recall. The need to rely on memory has been so dramatically changed by the instant accessibility of a library’s worth of information on your iPhone. It’s hard to know how it will affect their lives and their use of their internal memory systems.

You have four young kids. Any memory or learning lessons for them?

The principle of “Do it again, do it again and do it again.” Practice makes perfect is a principle that has stood the test of time. It is the ultimate driver of skill. As a memory scientist, I will add two twists: One is doing it yourself rather than watching someone demonstrate. You learn by doing. The other is distributed practice. You learn best when practice is spaced out over time. Even when knowledge is not firmly cemented, it’s important to not rely on crutches. For my children I try to instill a love of learning, which is something all parents should strive to do with their children.

What’s the Restoring Active Memory project that you’re doing for the Pentagon?

Neuroscience has already mapped out in great detail what physiologically the brain looks like in storing, finding and retrieving memories. If we could stimulate the brain into states that are optimal for learning and recall, we should in theory be able to improve memory function in a human being. That’s the key idea from this project.

Medtronic [a medical device manufacturer] will be developing a 256-channel brain stimulator, not only to stimulate but to record and analyze brain activity and [to] try to modify and synthesize it within the brain.

The ultimate goal is to send patients with memory disorders home with a device implanted into their brain to improve their memory.

How will the study work?

The 256-channel device will be far more than a brain stimulator. It will be an intelligent device that continuously monitors brain function for signals that indicate how well our memory system is operating. As it tracks these signals, in real time, it will use mathematical models of brain function to determine whether and how to stimulate at each of these locations. By cycling very rapidly between recording, analyzing and stimulating, it will try to continuously maintain good memory function in patients with neurological injury or disease.

Why are you using epilepsy patients for the study?

Before a physician would recommend surgically implanting a brain stimulator to help restore memory function in a patient with traumatic brain injury or dementia, he would want to have compelling evidence that the stimulator has a good chance of working. The patient and their family, guided by their physician, would only undergo such a treatment if the benefits clearly outweigh the risks. In the case of brain stimulation for memory restoration, we are at the very earliest stages of the research, and as such we are carrying out our studies in patients who already have electrodes implanted in their brains for another reason.

In particular, we are working with patients who have uncontrolled epilepsy and who are thus candidates for a neurosurgical procedure in which they have electrodes implanted throughout their brain in an effort to find the root of their seizures and remove the offending brain tissue. Such patients can participate in our studies without incurring significant risk.

The first human trials are expected to begin [this month] in seven hospitals across the country.

Could this help people with Alzheimer’s?

While brain stimulation is very unlikely to be a cure for patients suffering from dementia, it could potentially help such patients during what we believe to be a very protracted period in which the disease produces mild cognitive impairment while the patient is still highly functional.

Niiler regularly interviews scientists about their work for The Post.