One day not long ago a 27-year-old woman was brought to the Tel Aviv Sourasky Medical Center, sleepy and confused. Fani Andelman, a neuropsychologist at the center, and colleagues gave the woman a battery of psychological tests to judge her state of mind. At first the woman seemed fine. She could see and speak clearly. She could understand the meaning of words and recall the faces of famous people. She could even solve logic puzzles, including a complex test that required her to plan several steps ahead. But her memory had holes. She could still remember recent events outside her own life, and she could tell Andelman details of her life up to 2004. Beyond that point, however, her autobiography was in tatters. The more doctors probed her so-called episodic memory—the sequential recollection of personal events from the past—the more upset she became. As for envisioning her personal future, that was a lost cause. Asked what she thought she might be doing anytime beyond the next day, she couldn’t tell them anything at all.
The patient, Andelman realized, hadn’t just lost her past; she had lost her future as well. It was impossible for her to imagine traveling forward in time. During her examination, the woman offered an explanation for her absence of foresight. “I barely know where I am,” she said. “I don’t picture myself in the future. I don’t know what I’ll do when I get home. You need a base to build the future.”
The past and future may seem like different worlds, yet the two are intimately intertwined in our minds. In recent studies on mental time travel, neuroscientists found that we use many of the same regions of the brain to remember the past as we do to envision our future lives. In fact, our need for foresight may explain why we can form memories in the first place. They are indeed “a base to build the future.” And together, our senses of past and future may be crucial to our species’ success.
