Recap Studio, and a rabbit hole about how fast we can actually see

I get overly nostalgic (or perhaps I get THE EXACT RIGHT amount of nostalgic). This tends to shake out in a few behaviors, one of which is a disproportionate willingness to look at old photos and videos.

I was scrubbing through Lightroom last night, moving as quickly through photos taken in the month of July as possible, and I was struck by how well the images were visible and fun to watch at high-speed. This morning, I got up before the family for some quality PSALABGO (Porch Sitting And Looking At Birds and Goofing Off) and started putting together some scripts that could help me produce the video in a more structured way. Once those worked, I converted them into a VERY simple macOS Native Application.

I am pretty happy with the tool. Code’s on GitHub if you want to peek.

The process led me down a rabbit hole of human perception speed:

• Potter, Wyble, Hagmann & McCourt (2014), “Detecting meaning in RSVP at 13 ms per picture” — THE study showing people can pick out a named target from a rapid stream of images shown for just 13ms each. https://link.springer.com/article/10.3758/s13414-013-0605-z
• MIT News coverage of that study, explaining it in terms I can understand. https://watchers.news/2014/01/18/mit-neuroscientists-find-the-brain-can-identify-images-seen-for-as-little-as-13-milliseconds/
• THE actual speed you need to see and react. ScienceABC’s summary distinguishes the 13ms recognition threshold from the roughly 400 to 500ms it takes for a full perceive-and-respond cycle. https://www.scienceabc.com/humans/how-fast-can-the-human-brain-process-images

Apparently we have a function called the Critical Flicker Fusion (CFF) that responds very quickly to anything that could be predator or prey. Pretty remarkable stuff, we can react in 15ms, which led me to ask “Is that even fast?”

TLDR: Not really.

• Fast-paced lives demand faster vision (237-species CFF study, ecology and speed): https://phys.org/news/2026-02-fast-paced-demand-faster-vision.html
• In the fast lane – CFF comparison across species including flies, birds, humans (Ophthalmology Times): https://www.ophthalmologytimes.com/view/fast-lane
• To a Dragonfly, You Might Be Moving in Slow Motion (CFF explainer, insects and birds vs. humans): https://a-z-animals.com/articles/to-a-dragonfly-you-might-be-moving-in-slow-motion/
• Small birds’ vision: Not so sharp but superfast (pied flycatcher CFF study, EurekAlert): https://www.eurekalert.org/news-releases/505824
• Does critical flicker-fusion frequency track the subjective experience of time? (Rethink Priorities, references Boström et al. 2016 bird CFF study): https://rethinkpriorities.org/research-area/does-critical-flicker-fusion-frequency-track-the-subjective-experience-of-time/
• Critical Flicker Fusion Frequency: A Narrative Review (human and animal CFF overview): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8537539/
• Critical Flicker Fusion – overview including insect optomotor/flicker fusion mechanics: https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/critical-flicker-fusion
• The speed of sight: individual variation in critical flicker fusion thresholds (human CFF variability study): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10984398/

Anyways, I made an app that makes videos of photos that play (too?) fast.