Hacker News Reader

Comment by mytailorisrich | Hacker News Reader

This ignores an important point that this is a game of elimination and contrasts.

For example in that taxi captcha, there are 4 pictures of trees and 5 pictures of vehicles. 1 vehicle is not identifiable, 1 is an utility van in the distance, and the remaining 3 are yellow cars. These yellow cars have phone numbers on the sides and signs on the roof (where visible).

My bet is that the 3 yellow cars are taxis.

(And as it happens yellow actually seems to be the most common colour for taxis throughout the world where taxis have a specific colour.)

It usually works out fine. On rare occasions it's tricky but then it's possible to request another captcha.

I think people are trying too hard to find problems. I find hard to believe the comments that blow this out of proportion.

View on HN

While you might guess that Yellow means Taxi in most of the world taxis aren't actually yellow. Around here they are mostly big dark Mercedes (many of them vans), maybe with some ads on them. And no big white sign on top either.

You just ignored the part where they show how you can figure out yellow means taxi in this set without having known it before. People are smarter than monkeys memorizing flash cards. They have the ability to spot patterns not previously recognized.

Perhaps, but it is still problematic.

The most important one was mentioned earlier. It offers an implicit advantage to Americans. In the olden days we would call this American-centric. These days we would call it prejudiced. Claiming that it is prejudiced is valid since it is effectively asking different people different questions. To the American, it is asking them to identify taxis. To a non-American, it is asking them to solve a riddle.

To highlight that point: most of your criteria relied upon cultural factors. Those taxis have no resemblance to taxis in my part of the world. Taxis in my part of the world are private vehicles with a small magnetically mounted "taxi" sign on the roof. There is no consistency in colour, little consistency in type of vehicle, and they most certainly aren't covered with advertising. I also wouldn't be surprised if there are a handful of utility van used as taxis in my city, since taxi companies offer accessible services.

The game approach also implies some degree of understanding of captcha's. The approach you outlined assumed that the unidentifiable vehicle would not be treated as a valid answer and that more than one image would have to be selected, so you can look for patterns. Knowing the rules of the game may be fine if you are playing a game. It certainly isn't appropriate in the case of operating a business or offering a public service.

Reply on news.ycombinator.com