It seems trying to force the activation shuts it of. I guess that is because we start expecting answers to come to us in a specific pattern.
As you notice spontaneous activation is very intuitive and connects with information that you already know consciously. I think this is one of the reasons it is so difficult to notice spontaneous activation since we seem know it already and usually have no specific idea how we gathered this knowledge, spontaneous activation could be taking place yet we dismiss it because we think, "But I already knew that".
Congratulations on noticing your spontaneous activation. It seems you had spontaneous activation on the most important part of the book 'for you'.
Alex