Shelf Fly

Which package gets noticed first?

Each matchup shows two versions of the same made-up product to a computer model of a fruit fly's eye and brain. The fly sees in blurry black and white, so it reacts to shapes and light-versus-dark, never to colour or words. Pick a matchup.

Ridgeline body wash. Same bottle in charcoal and in pale grey.

Charcoal bottle

Charcoal bottle, as a shopper sees it
What a shopper sees
Charcoal bottle, as the fly sees it
What the fly sees
Noticed more

Pale bottle

Pale bottle, as a shopper sees it
What a shopper sees
Pale bottle, as the fly sees it
What the fly sees
Noticed less

Charcoal bottle gets noticed first (a big win)

The fly's brain reacted 2.6 times more to Charcoal bottle than to Pale bottle.

We ran 5 versions of the fly and all of them agreed.

Why: Charcoal bottle has more light-versus-dark contrast, and that's mostly what a fly's eye picks up.

Fair test: both products take up about the same space in their photos, so size didn't decide this.

What this means: Charcoal bottle is more likely to catch an eye first on a shelf. It doesn't tell you which one people would rather buy.

pack appears Charcoal bottle Pale bottle 0 s 0.8 s
The fly's brain activity, from blank screen to 0.8 seconds after the pack appears.

How it works

Each pack is turned grey and shown to a simulated fly eye made of 721 lenses: a blank screen, then the pack appears and stays. Five trained versions of the fly's visual system watch that clip, and we measure how much its brain activity changes once the pack is on screen.

We also run a plain light-versus-dark measure with no brain in it, and check that both packs take up the same space, so you can see when a result is just about contrast or size.

What it doesn't tell you

Whether people would buy one pack over the other. A fly is not a shopper. This shows which pack is more likely to catch an eye first.

Want to try your own photos? The code is on GitHub and runs on a laptop.