The function implemented by f(x) measures the level of association of a word with a particular concept. The concept to which a word is associated is indicated by a value between 0 and 1, where a value closer to 1 indicates stronger association. The function seems to be selective for multiple concepts. 

From the experiments, we can observe that "Harry Potter" has a high association score of 0.95, indicating a strong association with a concept related to the Harry Potter series. Other words like "highway" and "guilty" also have relatively high scores, suggesting an association with their respective concepts. On the other hand, words like "Cold War" and "Quran" have lower scores, indicating a weaker association.

Overall, the function appears to measure the strength of association between words and various concepts, with higher scores indicating a closer association. Further experiments and testing with a wider range of words will help uncover more concepts that the function is selective for.