Apr 29, 2024 - Science

Memorable images slow our sense of time, study finds

Illustration of a woman reclining on the hands of a clock

Illustration: Sarah Grillo/Axios

When we look at memorable images, time appears to slow down, according to a recent study.

Why it matters: The findings could help inform efforts to develop AI that can sense the passage of time — arguably a key component of human intelligence — and improve our interactions with the technology, the study authors say.

What they found: Study participants (about 100) were shown images of scenes that were six different sizes and had six different levels of clutter for 300 milliseconds to 900 milliseconds.

  • They were then asked to judge whether they saw the image for a long or short time.
  • Participants were more likely to say they looked at smaller, cluttered scenes for shorter than the actual duration. Larger, sparser scenes — like an empty warehouse — appeared to be shown longer, Martin Wiener, a professor of psychology at George Mason University, and his colleagues reported in the journal Nature Human Behavior.

In another experiment, the researchers asked a different set of participants to look at images whose memorability had been previously rated.

  • They found participants believed more memorable images were shown longer than they actually were and were remembered more precisely.
  • And the longer an image seemed to be shown, the more likely a participant remembered it the next day.
  • Using neural network models of vision, they found more memorable images were processed faster and how fast an image was processed was linked to how long it seemed to last.

The big question: Why? says Dean Buonomano, a professor of neuroscience at UCLA who wasn't involved in the study.

  • "Is that a side effect of how the brain works or does it have a function?"
  • Other illusions — of colors and shapes — don't have a computational role in the brain but are a consequence of the brain's hardware that has an important role in another context, he says.

The intrigue: The finding suggests "we use time to gather information about the world around us," Wiener said in a press briefing.

  • "[A]nd when we see things that are more important, more relevant, more memorable, we dilate our sense of time in order to get more information," he said.

Yes, but: "It's not that everything that's longer must be more memorable," he said, adding that other factors can interfere with time perception.

The big picture: Time has long been considered a byproduct of perception, Wiener told Axios.

  • "We perceive things, stitch them together and say that happened before this and now have a sense of time"
  • "Now we're seeing time is an active part of perception and our brains control our sense of time in order to gather information."

What's next: Wiener said he hopes the study inspires more work in AI and computer vision fields to "build systems that track and record and measure time."

  • "If we want to build AI that is interactive, that interacts with people the way we interact with each other, it needs to have a sense of time similar to ours.
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