This is the first installment in a series examining the psychology of time

Time marches forward, at a steady, consistent pace. Our perception of this pace—how we experience the passage of time—is neither steady nor linear; it is something else entirely.

We struggle to convey this dichotomy of time in everyday language, using clumsy phrases like “time stood still” or “time ticked by.” But what is it, really, to describe the feeling of time itself? Leave it to the Germans to provide the perfect word for this complex relationship: Eigenzeit, which roughly translates to the time inherent in a given process. It’s a combination of eigen (one’s own) and zeit (time).

A plant growing has its Eigenzeit, as does a person working in a state of boredom, and an athlete operating in a flow state. The term highlights the idea that our personal experience of time is often shaped by context, activity, and our psychological state, rather than by an external, uniform standard. Time passes much differently than a clock would lead us to believe.

While Eigenzeit as a concept gets us started in the right direction, there’s much more to explore in this relationship between absolute time and psychological time; what time is, and what time feels like. What is time at the level of the brain and at the level of our psychology? When we examine these questions through the lens of neuroscience, we arrive at a bizarre, almost inexplicable insight: psychological time doesn’t merely move along linearly. Instead, it has a completely separate dimension: Time has a density.

What does it mean for time to have a density, and how can neuroscience help us understand this? Let’s dive in.

From Time’s Elasticity of Speed to Its Elasticity of Density

We perceive time, psychologically, as a series of passing moments, what William James called “the specious present,” referring to our perception of the present moment as it seamlessly connects past and future. In this way, time has a single, simple, and straightforward dimension.

As we’ve seen, though, the speed of time is highly elastic, expanding or contracting by the novelty we’re taking in. Yet another trip to work along the same old commute you’ve done hundreds of times already? Zero novelty. We look back on this memory, and it feels as though it happened in an instant. On the other hand, it’s the instances where we’ve mixed up our routine—perhaps taking the train to work or going a completely different route—which stretch out our experience of time, making it feel much longer.

Time speeds up and slows down depending on the degree of novelty. Moreover, the pace of time is only one dimension; it also has depth - it exists along a spectrum between thin and thick. It shapes the feeling of time’s passing; it’s Eigenzeit.

This concept of the depth of time may sound abstract or metaphysical, but it’s ultimately grounded in neuroscience. It’s not about bending time itself but about our brain’s state as time passes. As we move forward in time, the moment also has a depth. Time doesn’t just stretch between slow and fast; it also stretches between thick and thin. It’s the feeling of how rich the passing moment is.

Working Memory as The Psychological Density of Time

The “specious present,” as William James described it, is seldom actually present. We’re constantly conjuring up information from the past and projecting our thoughts and imaginations into the future. Imagine you’re watching a film. A plot twist in the 35th minute only becomes meaningful when it leads us to retrieve information we witnessed earlier on, and this new framing then makes us wonder how the characters will respond as the film moves forward. Information in the present is integrated both with the past and with the future.

This perpetual integration—for information to be held in mind, for it to conjure up existing knowledge and memories, and for these in turn to spur thoughts about the future—is a crucial mental mechanism. This process is known as working memory, and it connects new information with the old, creating a continuous link between memory and future projection.

Put simply, working memory is what gives time a psychological thickness. We’ll come back to this idea of thick time shortly. But first, what is working memory and how does the brain enable this?

The Neuroscience of Working Memory

Imagine that someone tells you their phone number but you have no way to write it down. You’d have to hold it in mind for a given period of time until you found the means to do so. This is your short-term memory: your brain’s ability to hold information in mind.

Now imagine that while you’re holding this phone number in mind, the person tells you, “Oh sorry, the 4th digit is actually a 6, not a 4.” This requires a slightly different ability called working memory. In this process, you're not just holding information in mind; you're also retrieving, analyzing, and manipulating it. Working memory means that you’re not only holding this information, but you’re “doing work” on it. And when it comes to the neuroscience of time perception, this means integrating the present moment with memories of the past and with our projections for the future.

Working memory is invoked in a variety of scenarios—from doing math problems in your head to visualizing a scene unfolding in your mind. Neuroscientists long thought that, when it came to processing a given experience, such as watching a film, a specific, specialized process was engaged to hold this information in mind. That is, the eyes and ears take in the sights and sounds, these are processed in their respective sensory regions, and then this information is sent to our “working memory” center to hold temporarily and ultimately lay it down into long-term memory. Imagine information coming through on a conveyor belt, stopping at different stations along the way.

Recent research, however, calls this view of working memory into question. Instead of viewing working memory as a distinct brain mechanism, recent research suggests that it may be a property of the brain as a whole. That is, as we’re watching a movie, for example, regions across the entire brain are tracking, analyzing, holding this content in mind, and recalling it when necessary.

Ultimately, this holistic view of working memory brings us back to the idea of time’s thickness—its depth and texture, shaped by our mental state, our identity, and the brain’s vast network of interconnected processes. This is where we’ll pick back up Part 2.

This is a multi-part series on The Psychology of Time.

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References for Working Memory and The Psychological Thickness of Time

Nowotny, H. (2018). Time: The modern and postmodern experience. John Wiley & Sons.

Nowotny, H. (2019). Eigenzeit. revisited. Mediated Time: Perspectives on Time in a Digital Age, 67-85.