We’re often told to “be here now.” Yet the mind is rarely tethered in place. We take mental trips to our past, revisiting what happened yesterday or when we were children, or we project into an imagined future: tomorrow’s dinner date, the trajectory of our career at age 50.

Rather than a diversion from the norm of mindful presence, this tendency to internally visit other time lines, called “mental time travel,” is common; young adults, for example, think about their future an average of 59 times a day. Psychologists have suggested that this ability to time travel from the confines of our own heads is a fundamental aspect of what it means to be human.

The past and future are not locations that remain the same regardless of who is visiting and when. The way we envision our past or future is ever-changing, and the construction of these scenarios has an impact on what we do and how we think in the present. Until recently, the study of mental time travel largely focused on individuals and their personal histories. But this doesn’t reflect the social nature of our lives. Identities are comprised of groups that nestle into one another. We are part of our families and friend circles, occupational networks, countries and nations, and ethnic groups. The study of mental time travel is starting to reflect this: When we travel through time, we don’t always go alone.

Research on “collective mental time travel” shows that the way we imagine the collective future or past also impacts the present. It can sway attitudes toward policy decisions and laws, as well as how aligned people feel with their country or existing systems. It can affect a person’s willingness to engage in prosocial behaviors, like voting, donating, or activism. Because of this, collective mental time travel is more than just a neat cognitive trick—it provides an opportunity to be more intentional about how we represent the collective past and future. 

In the 1980s, psychologist Endel Tulving proposed that humans have the ability to relive their past and pre-experience the future, theorizing that the same memory mechanisms were used for both. This was supported by case studies with amnesiacs: One man, “K.C.,” had brain lesions that affected his ability to retain personal memories, like a visit he’d taken to a family lake house. This patient couldn’t imagine going there in the future, despite knowing that his family owned the house.

More recent brain imaging has supported Tulving’s theory by showing that similar networks are activated when remembering the personal past and personal future, said Karl Szpunar, an associate professor of psychology and director of the Memory Lab at Toronto Metropolitan University. Based on this evidence, some scientists think that we imagine the future by recombining past experiences—this is called the “constructed episodic simulation hypothesis.”

For the collective past and future, the story may be more complex. Is our collective future simply made up of fragments of the collective past? Intriguingly, when people with damage to their hippocampus, a brain region involved in personal memory, are asked about collective future events, like “What environmental concerns will the world face over the coming decade?” they are able to come up with answers. Even though their ability to mentally time travel into their personal futures was compromised, the ability to imagine events affecting a group’s future was intact. More work on this is needed, but as Spzunar and his colleague wrote, “The capacity to engage in collective future thought appears to rely on cognitive processes distinct from those involved in individual or personal future thinking.”