Collocation

What made you decide that?

Wh-question + causative verb + pronoun + bare infinitive B1 Wh-question + causative verb + pronoun + bare infinitive

This question asks for the reason or motivation behind someone's decision.

Definition

'What made you decide that?' is a common English collocation. This question asks for the reason or motivation behind someone's decision.

What + make (past tense) + object + bare infinitive + object pronoun?

“What made you decide that?”

After hearing his surprising announcement, I asked him, "What made you decide that?"
She looked at the new car in the driveway and wondered, "What made you decide that?"
"I'm moving to Australia next month." "Oh, really? What made you decide that?"

Show more examples

When he changed his mind about the project, his boss inquired, "What made you decide that?"
"We're going to try a completely different approach this time." "Interesting, what made you decide that?"
Seeing her wearing a new, vibrant color, her friend smiled and asked, "What made you decide that?"
The sudden career change puzzled everyone. "What made you decide that?" was the most common question.
"I've chosen to work weekends from now on." "Weekends? What made you decide that?"
After a long pause, she simply asked, "What made you decide that?" wanting to understand his motivation.
His abrupt departure from the team led colleagues to ask, "What made you decide that?"