What day is it? How holidays warp our sense of time

The holidays are coming and chaos is upon us. You may be navigating crowded parking lots in the heat, shuffling from one holiday party to the next, not to mention trying to avoid recently arrived relatives. Amid this chaos, you might experience time a bit differently.

You might forget what day it is. New Year's Eve might sneak up on you when Christmas felt like it was just yesterday. And before you know it, the holidays are over, the trays of mangoes are gone, and the relatives have packed up and left.

That's not the only way your sense of time may be a bit distorted over summer.

While sitting around and reflecting on past holiday seasons, you might find last Christmas feels just like yesterday. In fact, it might feel more recent than something that happened a few months ago.

While it might seem like there's a temporal vortex every December, these distortions make sense when you understand how the mind perceives time.

How does the mind perceive time?

The mind can't perceive time directly. We don't have watches, hourglasses, or calendars in our heads. Fortunately, the mind is quite good at approximating things it can't measure directly.

Our vision does this regularly. We can't measure depth with our eyes, but we can approximate how far away objects are using various cues in our environment. Objects further away are smaller in our visual fields, less textured, and move less than objects closer to us. While this isn't perfect, it serves us well enough for us to navigate our environments.

Our minds do something similar with time. We use cues from both our environment and our memory to indicate how much time has passed.

There are often a number of cues in our environments that signal what day it is. If you work 9 to 5, working or commuting only happens on weekdays; going out for brunch or playing tennis during the daytime only occurs on weekends. Our minds combine each of these cues to give us a sense of what day it is.

Many of these cues are disrupted when we go on holidays. We're no longer working, which means the events that normally signal to our minds it's a weekday are gone.

Several of the things we do on holidays, such as going to parties and having big dinners with our relatives, are things we usually only do on weekends, but can occur any day of the week on holidays.

This disrupts our mind's reference points for what day it is. This is why the holiday period might feel like one long weekend even though you know that's not the case.

Where do memories fit in?

There are many cases where we lack external cues to give us a sense of how much time has elapsed. Fortunately, we can use our memory to fill in the gaps.

You don't need a memory scientist to tell you that more recent memories tend to be more vivid and detailed than older memories. So, the vividness of a memory is another cue we use to figure out how long ago an event occurred.

I might see somebody who looks familiar but I can't recall their name or how I met them. It's probably safe for me to say I didn't meet them very recently.

Using memory to gauge time would work consistently if memories always got worse as time progresses.

However, there are circumstances where memory for an event can improve with time. A great deal of experimental research has found memories for certain events improve when we return to the conditions in which the memories were formed.

This is because we form memories by linking various aspects of an event - the location, the people at the event, the music we were hearing - together in our minds. When we attempt to remember something, we use various aspects of the event to retrieve the others, much like using a Google search.

Remembering past Christmases

In the holiday season, we often return to the circumstances where previous holiday memories were formed. We're often surrounded by the same people, eating the same foods, and hearing the same holiday songs.

This gives our minds additional cues to retrieve memories from past holiday seasons, such as gifts you may have received or arguments that happened over the dinner table.

So, you might find yourself remembering a lot more memories from past holidays in greater detail and vividness than before. Because the mind uses vividness as a basis for time perception, this might have the effect of last Christmas season feeling like it was just last week, instead of a year ago.

If your sense of time goes a bit haywire over the holidays, don't worry. When you return to the structure of your daily life, your sense of time and memories will go back to normal.

Adam Osth receives funding from the Australian Research Council.