DAVID: You are right. The leader makes a choice of two alternatives, this path or that. Not much thinking involved. Just pick one. May not need any judgement at all.

dhw: Then what on earth was the point of the test? Hundreds of tests have been carried out to show that ants make intelligent decisions.

DAVID: This study concerned individual actions of the nest when a group is active.

There wouldn’t be much to study if there weren’t individual actions and if the group was inactive.

DAVID: Our cells make much more complicated decisions on their own, with each cell programmed to choose in concert with his fellows so an organ runs properly.

dhw: Of course our decisions are more complex. But if our cells make complicated decisions on their own, they are not programmed. The leaders decide, the rest follow.

DAVID: Our cells are programmed to work together for proper organ function.

You say the cells are programmed. The article says the cells make complicated decisions on their own.