In case you are wondering, I’d offer a hesitant yes to this question regarding Jenna(29 months). She correctly identifies quantities of three about 80% of the time. There is no way she is ready to move on to four yet, despite her ability to “count”, i.e. rattle off numbers without correspondence. I got a pretty accurate understanding of where my daughter’s thinking currently resides, by trying out lesson 1 from Right Start Level A. You can download the first few lesson plans yourself for free and give it a try with your own two year old.
I wish I had known to try this experiment with Bruce (6.5) when he was two, because of course I’m now uber-curious what his thinking was back then. When did the quantities three and four really solidify for Bruce? When will they solidify for Jenna? The Psychology major in me is going to be periodically checking to figure this out. Looking forward in lessons 2 and 3 of Right Start Level A, the other two abilities to monitor are A-B-A patterns, and sorting.
The reason why I decided to investigate all of this to begin with, was that I have just finished reading Keith Devlin’s wonderful book The Math Instinct: Why You’re a Mathematical Genius (Along with Lobsters, Birds, Cats, and Dogs). This book was well written, meticulously researched, and thought provoking. The final chapters reaffirmed everything I learned about Constructivist math in my professional development as a teacher. The research he presented about young infants understanding the quantity of two was especially fascinating. I had previously been proud of Jenna understanding the quantity two. Now I realize that’s no big deal!
I’m going to continue on reading more of Keith Devlin’s books. I’m not a “mathy” person myself, but he writes in a way that is easy to understand… even for someone who hasn’t studied Calculus since 12th grade. 🙂