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Comment by br3d | Hacker News Reader

I think what's way more interesting is that dogs can master class inclusion: they can understand that this toy is "Mr Shakey" and this toy is "Elephant" but they can also understand that there is a superordinate category of "toys" that includes both Mr Shakey and Elephant, and when asked "Go and get me a toy" can choose either. This is mind-blowing, as children normally have to reach 7 or 8 before they have a solid grasp of class inclusion [0]

0 https://www.jstor.org/stable/1129264#:~:text=showing%20relat....

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I did not read the paper, so I cannot comment on the "solid grasp of class inclusion", but regarding the capacity that you described in your comment, I have a 2-year-old and it's been a long while since she has mastered this (book vs this book, toy vs toy, fruit vs an apple and so on). As far as I know, most two year old have already acquired this concept.

(EDIT I see the other comment says something similar and you have replied)

I didn't even know "class inclusion" was a thing really. Though obviously the concept makes sense.

My daughter had a solid grasp of it definitely around 16-18 months. She could easily talk about books or toys, cars, food, drinks etc.

Not sure if this is unusual but 7-8 as the other poster mentioned sounds crazy late for that kind of conceptual understanding to appear.

Yeah, it's not really convincing that it can typically take up to 7-8. By that age kids are already able to read, write and do basic math, which of course requires them to understand "classes" like numbers and letters, such that they could handle both "write a number" and "write 23".

I did not know what class inclusion was, but now I'm thinking it's more complex than that? After a little bit of reading. "all daisies are flowers" and not "all flowers are daisies", this example seems more like the "solid grasp" you're referring to. And not basic categorization that a 3 year old might have: "foods", "toys"

Hmm, I'm now struggling to remember basic developmental psych, but there's definitely a phase at which linguistic children struggle with things having two names (it can't be both "dog" and "Rex") but I think you're right - this phenomenon is subtly different to class inclusion. But either way, dogs can do something with language comprehension that speaking children can't, which is the bit I find really interesting

I need to read up more on this because in my extremely small sample size this kind of dual naming understanding came in really early with my daughter.

I feel like it's a linguistic subtlety that us adults are struggling with conveying the exact concept.

My niece and nephew are being raised semi bilingually and they were happy to accept things could have multiple names before age 2 IIRC. The youngest only just turned 2.5 and can happily flick between Chinese and English (though has a bias towards English because that's what she hears more by a big margin)

Will be interesting how my future kids will be as they will be pretty much exactly 50:50.

My daughter is bilingual too. I wonder if that has something to do with it.

They can also be taught certain distinctions within a class after having recognized the class itself.

For instance my pup picked up pretty early on that it’s big fun to chase birds. Where we lived at the time there were few crows (I honestly don’t recall seeing any), and when we moved to Seattle where crows are many she of course wanted to chase them too. But since I know that it’s better not to make crow enemies, I taught her not to chase them specifically. She now recognizes (usually) that crows are off limits, but still understands that other birds are generally fair game. (I don’t know if she’s also picked up on the fact that the crows recognize her too, but they definitely do.)

I don't know if it's a solid grasp of abstract class inclusion so much as the concrete difference between "let's play (with a toy)" and "go get this specific toy (which will prompt play)" but yes, it's still impressive.

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