Comment by mauvehaus

9 hours ago

> All 21 pelican-bicycle images, across all seven labs, face right. No other animal/vehicle combination does that.

> However, facing right is common: 60% of all 1,008 images do it. How common depends on the animal and the vehicle, and bicycles are one of the two vehicles where it’s strongest

Of course the pelican on the bicycle is facing right. The drivetrain on a bicycle is on the right side. If you want any representation of a bicycle that shows the drivetrain you're going to show the right side of it if you want to do so without the frame occluding it. It's an excellent bet that their training data reflects this.

Citation: https://www.rei.com/c/bikes

Edited to add:

As near as I can tell, all of the bicycles are shown facing right, regardless of the direction the animal is facing (GPT 5.6-Terra, Sample 1/3). Also, in every case where the rider has legs (i.e. not the whale) both of the rider's legs are on the right side of the bicycle. This suggests a pretty serious lack of actual understanding of how a bicycle works.

5 comments

mauvehaus

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cheesecakegood  5 hours ago

Interestingly, there was an artist a few years back who (for an unrelated project) had almost 400 people across a range of ages draw a bicycle and 75% of those faced left! So this seems to actually go slightly against the human drawing intuition.

https://www.gianlucagimini.it/portfolio-item/velocipedia/

On the other hand, I notice that the prompt says to draw a pelican riding a bicycle, implying motion... and since most of us read left to right, I think it's usually natural to draw an object in motion moving left to right as well, which means the bicycle should be facing right. So maybe that specific setup is more natural here.

Either way, for humans bicycles are actually really hard to draw from memory. In fact, I substitute teach, and sometimes as an activity I have my students draw bicycles from memory in 60 seconds. Most make pretty serious errors, usually the frame or chain connections: they can tell it's wrong but still can't draw a more correct one. I use it as an object lesson about the difference between recognition and recall - most students never realize that much of their studying can end up being the former, when tests and life almost always ask for the latter. This helps explain why many students go from "that makes perfect sense" when going over review problems to a total mind blank only a few minutes later (especially in math!).

  • ctidd  4 hours ago

    It’s a very strong convention in bicycle photography. The drive side is considered nicer looking, it’s where you get to show off the components, etc.

    Independent of what humans may do with the same prompt, training datasets will be full of traditional bike photos, which will all be drive side.

    It’s also one of the easiest yellow flags to look for in used bike listings (not low-end, but anything enthusiast level). If a bike is photographed on the wrong side, there’s a non-negligible chance it’s stolen, because the seller is presumed to know better if they’re an enthusiast themself.

  • sheept  1 hour ago

    That's interesting. I think the bikes-facing-left bias probably comes from how humans use bikes: the kickstand is on the left, so people likely hold and approach bikes from its left.

    Looking online, the kickstand is apparently on the left to avoid the gears. Based on the other comment about bike photography, it's interesting the same design choice makes humans and cameras/LLMs see bikes from different sides.

  • userbinator  4 hours ago

    I wonder how the skill at drawing a bicycle compares between the general population, and those who own or ride one regularly.