Spontaneous activation on more than one book of the same general subject causes more of a direct learning type of effect. You'll need to give it a couple of weeks to realise (or maybe even a friend notices first) that you have acquired a new skill of knowledge about the subject.
If you want to experience spontaneous activation. Photoread a book that someone else has read and knows fairly well. Give yourself time to let the inner mind process it and then let them ask you questions about the book. Get them to start out with true or false questions and then see what else you can answer about the book when they ask. You'll find the book activating this way.
There is another post that discussed this in a bit more detail. When I first saw it I thought it would be interesting to try though I didn't know who to try it with since both of my brothers are dyslexic they avoid books. I wound up doing it accidently though an msm chat. I photoread a business planning book to help someone with their school assignment. When he first asked me to help him I had no idea where to start. I found a business planning book photoread it with the intent of manually activating it while at the computer helping this student with the assignment.
When he started quizzing me. Step one ... what next, what else, I found the answers coming up without opening the book. I never even opened the book again even though I had it beside me. I was personally surprised how important I considered looking into insurance as a factor for starting a business in Australia. The following morning I wondered where the information came from. I opened the book to a section within a chapter talking in detail about insurance.
It wasn't until the following morning that I realised that I had spontaneously activated the book. When he first asked me where to start my mind went Oh No... couldn't he have an easier assignment? Where the heck do you start when you plan a business. Lucky for me I had been invited out for dinner. When I came back at 8:30 I PRed the business planning book. Because of other assignment he said he was shelving the business planning one. 11pm the conversation came back to the assignemnt. in the next 45 minutes from the information I gave him he wrote an essay that scored 70% losing marks for wrong layout. When he first present me with the assignment neither he or I knew where to start. It was an interesting way to experience spontaneous activation. 
Alex
