Color matters

Isaac has an unusual quirk: When he plays, he often likes to have TWO of whatever toy it is that he's playing with—and those two toys are usually red and yellow. Allow me to demonstrate:

Isaac prefers to play with the red and yellow cars:

Isaac prefers to toss the red and yellow balls:

Isaac prefers to roll the red and yellow nesting barrels:

And Isaac prefers the red and yellow stacking cups:

If anyone dares to take one of Isaac's red and yellow toys from him, he freaks out. The only way to calm him down is to retrieve the purloined item; with both toys back in his possession, he is as happy as a clam.

I've been trying to come up with an explanation for this rather odd behavior. (He doesn't have any developmental or language delays, and the kids' 18-month autism screening threw up zero red flags, so I'm not worried about that.) Here are my theories:

1. Isaac may be a wee bit obsessive compulsive. (Kind of like his daddy, ha!)
2. Isaac may be color blind. (The condition runs on both my side and Ted's, so it would not be surprising if this were the case. It could be that red and yellow are more brilliant and, therefore, more attractive to him than other colors.)
3. Isaac may be a combination of 1 and 2.
4. Isaac may be merely acknowledging his ancestral Spanish heritage:

Whatever the case, I'm willing to bet this kid is gonna want ketchup and mustard on his hot dogs the minute he figures out that it's an option!