Do Dragonflies Live in a "Slow-Motion World"? Your Screen is Like a Club Strobe to a Fly ─ The Different "Density" of a Second for Living Creatures

Do Dragonflies Live in a "Slow-Motion World"? Your Screen is Like a Club Strobe to a Fly ─ The Different "Density" of a Second for Living Creatures

1. "The Same One Second," Yet Different Perceived Density

The screens of our smartphones and PCs switch light at a very fast cycle, yet humans barely notice any flicker. However, if a fruit fly were to look at the screen, it might perceive it as a club with intense strobe lights flashing. This metaphor begins an article that vividly conveys the differences in how animals perceive "time."


The ability that creates this difference is how finely the visual system can segment time to gather information. While fast-moving objects may appear "blurred" to us, they might look like a "series of detailed photographs" to other animals. Conversely, for animals adapted to slow movements or dark environments, the movements we take for granted might be too fast, causing the world to appear as a vague blur.


2. Measuring "Temporal Resolution" in Research—What is CFF (Critical Flicker Fusion Frequency)?

A commonly used metric in this field is the "Critical Flicker Fusion rate (CFF)." This is the point where increasing the speed of a flickering light makes it appear as a continuous light rather than flickering. The higher this threshold, the more changes in short time intervals can be distinguished, indicating higher temporal resolution.


The analysis introduced here gathers existing data from a wide range of animal species to examine on a large scale what influences the temporal resolution of vision. The abstract of a paper published in Nature Ecology & Evolution states that it tested the relationship between ecological pace and perceptual tempo using a comparative method considering phylogeny (evolutionary closeness) across 237 species.


3. Species That "Live Fast" See the World in More Detail

In summary, "Temporal resolution is not random; it is strongly linked to the speed of life."


The article provides examples such as humans having a CFF of about 65Hz (able to distinguish up to 65 flickers per second), while some birds exceed 100Hz, and insects like tsetse flies and dragonflies reach around 300Hz. Dogs are said to have a higher CFF than humans, while deep-sea fish, starfish, and large snails have extremely low values.


Why do such differences exist? The key concept is that "high temporal resolution is 'high-cost,' and it is only worth the investment for species that live fast." Activities like flying, chasing and capturing prey, making sharp turns, and instantaneous decisions that are life-or-death require information from slight time differences. The abstract also indicates a link between flight capability, pursuit predation, and high temporal resolution.


4. In the Ocean, "Smaller Means Faster Perception"

Another interesting aspect is the influence of environment and body size. The article mentions a tendency for smaller species to have faster vision in aquatic environments. Small, agile fish have relatively high temporal resolution, while large species like giant sea turtles have lower resolution.


While it's not entirely clear why this relationship is stronger underwater, it is suggested that "water allows for more instantaneous changes in movement (acceleration and direction changes can occur continuously)." In other words, the "quality of movement permitted by the environment" might reflect in the tempo of perception.


5. In Dark Worlds, "Photons" Take Priority Over Time

However, seeing quickly isn't always advantageous. In dark environments, temporal resolution tends to decrease. The simple reason is that in dark places, capturing "a moment of light" becomes the top priority. It's akin to slowing the shutter speed on a camera to capture more light. By making the response of photoreceptor cells "slower," weak light can be accumulated, but movement becomes more prone to blurring. The article highlights this trade-off with examples like deep-sea isopods and nocturnal geckos.


6. Imagining "The Perception of One Second" Can Reverse Worldviews

From here, the discussion moves to the "imaginative platform" provided by science. As philosopher Thomas Nagel's famous essay "What Is It Like to Be a Bat?" suggests, we cannot fully understand the subjective experience of other species. However, by measuring performance limits (how much can be distinguished), we can infer "how frequently the world updates for that species."


For example, for humans, "one second" is just long enough to barely track fast events. Falling cups, speeding cars, successive lightning strikes—most of these leave little detail beyond a "sense of having seen them." But for animals like dragonflies with extremely high temporal resolution, the same one second might resemble a video composed of "more frames." Situations where we perceive dragonflies as having super reflexes might, to them, appear as if the world is "playing in slow motion."


7. Reactions on Social Media: "Bullet Time" and "Display Issues"

 

This topic has a typical way of gaining traction on social media. A common metaphor is "smaller animals perceive time more slowly = bullet time (like in the movie 'The Matrix')." On biology threads on Reddit, there are posts attempting to intuitively explain why insects dodge quickly by suggesting they "experience time more slowly," leading to discussions in the comments about "the number of frames they see."


Another modern derivative is the argument, "Visuals and lighting intended for humans might appear unnatural to animals." For instance, when using video stimuli in animal behavior experiments, a low playback frame rate could result in "a choppy experience for the animal." This awareness is also present in research, with studies examining how the quality of visual presentations can affect behavioral responses.


On social media, this further leads to questions from a layperson's perspective, such as "How do birds and dogs watch TV?" "Does LED flicker stress insects?" and "Could this be a hint for considering pets' living environments?" While many aspects remain unexplored scientifically, even the broad concept that "the tempo of perception is a trade-off with ecology" serves as an entry point for reevaluating artificial lighting and visual environments around us.


8. Practical Impact of This Research

This theme does not end with just romance; it offers several practical implications.

  • Animal Welfare and Captive Environments: Flickering in lighting and displays, harmless to humans, might be stimulating for animals.

  • Ecological and Behavioral Research: Designing video stimuli, camera shooting, and lighting conditions to match the "temporal resolution of the target species" to avoid skewed interpretations.

  • Conservation and Environmental Issues: In discussions about the impact of artificial light on ecosystems (light pollution), "temporal fluctuations" could become as important as "light intensity."


Of course, CFF is just one representative metric of visual temporal resolution and does not fully capture the entire perceptual experience. Nonetheless, the significance of confirming the trend that "the faster the life, the faster the perception" across 237 species is substantial. Even if the world is one, the "frequency of world updates" varies by species—this concept quietly challenges our assumptions.


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