The moment the researchers start firing electricity into my brain, I feel a repetitive pinching sensation on the left side of my head. It’s prickly and annoying, just short of painful.
Robert Reinhart, a neuroscientist at Boston University who is demonstrating his research on me, assures me that the feeling will subside in about 30 seconds as the skin cells on my scalp get accustomed to the electric current passing through them. He’s right: The sensation soon downshifts to a persistent tingle — noticeable, but no longer irritating.
This makes it much easier to resume the memory test I’m trying to complete.
I’m sitting in a chair in a little room in Reinhart’s lab, wearing a cap of electrodes and holding a video game controller in both hands. On a table in front of me is a computer monitor that displays a series of images, each one flashed on the screen for less than a second. I am shown mundane objects such as a book, an abacus, a glass of orange juice, or, more incongruously, a creepy clown puppet. After a few seconds of whiteness, another image briefly appears. It’s either a repeat of the first object I was shown, or it’s the same object altered slightly. Perhaps the book’s pages are splayed or maybe there’s more juice in the glass. I’ve been instructed to hit buttons on the video game controller to indicate whether the object is just as I remember it from its first flash on screen, or whether it’s changed. I see a green check if I’m right and a red X if I’m wrong.
After a few minutes, another test begins. A series of lines appear on the screen, slanted either slightly to the left or slightly to the right. That image is instantly scrambled by a grid of squares, and I have to remember if the original set of lines slanted to the left or right.
These various tests are assessing my working memory, which is the ability to hold information in your mind over a short period of time. Reinhart compares it to a sketch pad. It’s how you keep the first part of a sentence…