The function f(x) appears to be selective for the concept of objects or entities that are associated with movement or transportation. It assigns a higher value closer to 1 to words that are commonly associated with vehicles or means of transportation, such as "car". It assigns lower values closer to 0 to words that are not typically associated with movement or transportation, such as "cat" or "tree". The closer the value is to 1, the stronger the association with the concept of movement or transportation.