Research shows that ice cream creates neurological changes in the brain that make us happy. And happy people are more likely to say yes - according to a campaign by New Zealand ice cream makers - Tip Top.

They created Yes Sticks. A way to harness the positive effects of ice cream to get something you want. People used a Facebook app to tell Tip Top what question they wanted to ask.

Then, Tip Top put each question on its own, unique Yes Stick inside the ice cream flavour the applicant chose. Each ice cream was hand delivered so people could give it to the person they were asking and the results were shared on social media.