"Often, even after years, mental states once present in consciousness return to it with apparent spontaneity and without any act of the will; that is, they are reproduced involuntarily"

This quote by Hermann Ebbinghaus suggests that memories and frame of minds can resurface in our awareness with no conscious effort on our part. This phenomenon is known as uncontrolled memory, and it happens when a previous experience or mindset is spontaneously remembered without any deliberate attempt to remember it. This can occur even after a long period of time has actually passed because the initial experience. Uncontrolled memory can be triggered by a variety of external stimuli, such as a familiar smell or noise, and even a particular feeling. It is believed that these memories are saved in our long-lasting memory, and can be recalled with no conscious effort. Ebbinghaus' quote recommends that uncontrolled memory is a powerful and mysterious phenomenon, and one that can have an extensive effect on our lives.