Wow, that was fascinating. For anyone else wanting to read the article, I would recommend looking at this non-labelled image first, and choosing which shape you would call Bouba and which you would call Kiki:

https://upload.wikimedia.org/wikipedia/commons/e/e7/Booba-Ki...

If you read the Wikipedia article first, you'll bias your own result on the test / experiment.

Also an interesting footnote at the end of that article:

"Individuals who have autism do not show as strong a preference. Individuals without autism agree with the standard result 88% of the time, while individuals with autism agree only 56% of the time."