Question

At two years old reynaldo seems to lack the ability to understand that other people have thoughts and intentions that are different from his own. reynaldo has most likely not yet developed __________.

Answer 1

Reynaldo has most likely not yet developed: theory of mind

Theory of mind is the ability to analyze the facts around us, and use it to form our unique beliefs and understanding. Without this, we wouldn't be able to understand other people's thought and intention.
At two years old, our human brain still hasn't fully developed and still missing a lot of its main functions. 
Reynaldo will most likely start to develop this function when he is around 5 years old.