Imagine your morning routine: First, you’re about to take a shower. You turn on the water and wait for it to heat up while you undress. Although you’ve never kept track, you know exactly when to step into the shower to avoid a shock from the cold water.

Now imagine you’re making some coffee. You fill up the pot with water, add your fresh grind, and turn on the coffeemaker. Then you get busy with other tasks. After a few minutes, you get a feeling that it’s time to check on your fresh pot of Joe. Sure enough, you enter the kitchen right before the machine beeps – it’s ready.

These are just a couple of examples of how humans can learn regularities in the duration between certain events and adjust their behavior in response. Timing research has shown that we can detect temporal regularities in our environment to anticipate not only what will happen, but also when it will happen. In fact, humans aren’t unique in this ability – even rabbits who have been conditioned to expect an air puff at a regular interval will close their eyes around the point of expected delivery.

So, we can learn to adapt to temporal events. But is this learning implicit? And can it be done in the face of distraction? That is, can people still learn about regular intervals even when they go unnoticed and are interrupted by irregular events?

Josh Salet, Wouter Kruijne, and Hedderik van Rijn (pictured below) aimed to answer these questions in their recent article published in the Psychonomic Society journal Psychonomic Bulletin & Review.

Salet and colleagues developed a task inspired by the popular ‘Whac-A-Mole’ arcade game. Three blue circle outlines appeared on a computer screen in a triangular position and indicated potential target locations. A fixation dot appeared in the middle. The goal of the task was for participants to move their mouse from the fixation dot to the target location (i.e., one of the blue circles) whenever the circle outline filled in. An example of the game can be seen in the video below:

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Example of gameplay. No moles were harmed in this version of the game!

Participants underwent two phases of gameplay. During the first phase (called the “explicit” phase), they were told that one of the locations was a “regular target location,” where the target would consistently appear every 3 seconds. At the other two locations, the targets would appear at irregular (random) time intervals.

During the second phase (the “implicit” phase), participants were told that the former regularity would no longer hold. However, one of target locations – a different location than that of phase 1 – still had a target appear every 3 seconds.

Another group of participants experienced the same procedure, but with the game phases in the opposite order (i.e., implicit-to-explicit).

In other words, a target always appeared in a specific location at a regular time interval, but participants were only given this information during either the first or second phase of the experiment.

Returning to the research question, can people still learn about regular intervals even when they go unnoticed and are interrupted by irregular events? Yes!

Participants were both faster to respond and more accurate when the target appeared in a regular location compared to an irregular location, and this was especially true when participants were told to expect regularity in one of the locations.

In addition, participants were quicker to move their cursor toward the regularly timed target than the irregularly timed targets, as if they were anticipating the upcoming event.

And, in a questionnaire administered at the end of the experiment, only a few of the participants indicated any awareness of the regularity during the implicit phase of the game.

These results suggest that participants were not only able to adapt to the regular target interval intentionally, but also implicitly without detecting its presence.

According to Salet,

Temporal implicit behavior is quite amazing. Although the 3-second regularity seems very obvious, especially for me, rarely anyone noticed it. Yet, unaware participants acted as if they were expecting the regular event.

The creative use of the ‘Whac-A-Mole’ game is a great example of how the lab can be used to measure temporal behavior under conditions that are more representative of everyday life, where events unfold in complex time sequences without our explicit awareness. After all, the same ability that helped participants whack the most “moles” also keeps us from freezing ourselves in the shower and pouring our morning coffee at its freshest moment.

Featured Psychonomic Society article:

Salet, J. M., Kruijne, W., & van Rijn, H. (2021). Implicit learning of temporal behavior in complex dynamic environments. Psychonomic Bulletin & Review. https://doi.org/10.3758/s13423-020-01873-x