The function f(x) appears to measure the association of each input word with a specific concept. It assigns a value between 0 and 1 to each word, where a value closer to 1 indicates a stronger association with the concept. The function is selective for multiple concepts, as indicated by the different values assigned to each input word. 

To gain a more comprehensive understanding of the function's behavior, it would be beneficial to run experiments with a diverse and random selection of words spanning various categories, including common and obscure words, concrete and abstract words. This would help in determining the specific concepts that the function f(x) is selective for.