The function f(x) appears to be selective for words related to nature and the outdoors. It is more likely to return a high value (close to 1) for words that evoke images of nature, such as "water", "mountains", "outdoors", and "nest". On the other hand, it is less likely to return a high value for words that are more abstract or have no clear connection to nature, such as "shy", "language", and "pawn".
Based on my experiments, I can also see that the function is not strictly selective for any one concept, but rather it seems to be sensitive to a broad range of words that are related to nature and the outdoors.
I hope this helps! Do you have any other questions or would you like me to run more experiments?