Is There a Cost to Multitasking?

Human beings, as I understand it from the cognitive science side, can't really multitask. We can do one thing at a time. And when we are doing several things at a time, what's actually happening is that we're switching between them and that also has a cost. So I think that this acceleration of everything moving more quickly is making us think less deeply and it is also making us more shallow in a sense that we just can't keep up with things, right?