Breast Fed Babies are Smarter

Did you hear about this study that says that  babies that are breast fed exclusively are smarter than babies that had formula?  Now I have to wonder:

I nursed Ally for 10 1/2 months, exclusively, until she went on a nursing strike and switched over to formula for 1 1/2 months. From then on she started on milk, and homemade, organic baby food.

Aedan, I nursed until he was 2 1/2 years old. His only experience with a bottle of formula was when he was 2 weeks old, I had surgery and had to pump and dump for a bit until I was able to stop taking medications.  He ate organic food,  jarred food, whatever we all ate ( you know, 2nd baby syndrome) but he nursed longer.

Is one smarter than the other?  Did I give one more attention than the other?    I used those moments of "Only Aedan and I" as alone time with him as I nursed him, otherwise I was chasing a busy 3 year old and sharing my attention with her.  They are both smart, happy, well adjuted kids (well, mostly!)

I'm interested in hearing YOUR thoughts on this. Please share!