Throughout my life I have never been a fan of surprises. After reading about predictability and controllability I learned that most other people aren't fans of negative surprises either. Badia's experiment about this subject showed that most people like to know what is coming. Most people avoided the shock and were also more comfortable when they knew that it was coming. This experiment is usually tested on animals like rats, who also prefer knowing when they will be shocked. This experiment reminds me of scary movies. I like watching a scary movie much better the second time because I can prepare myself for when the parts where things jump out at you. Once the "shock" part happens I am fine but I am very uncomfortable when I do not know when it is coming.
The preparatory response hypothesis says that a signal preceding a biologically relevant event allows the organism to prepare for that event. This shows that even our bodies prefer to be prepared for a shock. By knowing when the event is coming we can avoid it and if we cannot avoid it we could at least prepare for it and reduce the stress that incurs. The book uses an example about exams as the exam being the stress. The days that we do not have exams are considered "safe" days because we do not have to worry about these stressors.