Anyone can focus and become absorbed in some everyday activity such as reading a book, watching a movie … and in that experience it’s not uncommon for some alteration of perception to happen. We can become so connected with the reading or watching that we become disconnected from our surroundings. This experience of connecting and disconnecting is much more available than “association” and “dissociation”.
This is so simple and common that we do not notice, but so easy to understand when you mentioned it.