Stimulate is a synonym of Urge. Urge is a synonym of Cheer. Cheer is related to Happy. you would Laugh because Happy. 
Mind is a type of Intelligence. Intelligence is related to Test. 
Stimulate <--Synonym--> Urge <--Synonym--> Cheer <--RelatedTo--> Happy <--MotivatedByGoal-- Laugh 
Mind --IsA--> Intelligence <--RelatedTo--> Test 