We discussed various facets of the power of sounds, and they all trigger emotions: Sounds can be alerting, calming, annoying, pleasing, bringing joy or sadness, putting us to sleep, or making us jump and dance. Many experiences are associated with sounds, and sounds play an important role in people's routines and habits: For hundreds of years, bell towers have kept time, sounded alarms, and announced weddings and funerals. Nowadays, the timer of the toaster-oven alerts us that our food is ready.

But sounds affect more than habitual actions. Do you have a special tune that triggers a special memory every time you hear it? Couples often have "their song". Music and sounds often take us back to places like our childhood home or college dorm, with vivid memories of events and a sensation of being flooded by the emotions of that time and place.

The power of sound to evoke strong emotions and emotional memories can be a rich source of creative ingenuity for experience designers.

Of course, we do not only hear sounds--we make a lot of sounds too. With the advancement of voice recognition technologies, designers are working hard on making the experience of having a dialog with machines effective and pleasant. Apple's Siri, Google's Assistant, Amazon's Echo, and Microsoft Cortana are competing artificial intelligence systems that introduce voice and sound interaction, as an integral part of the user experience. Humor has proven to be one of the successful design strategies in this context (as seen in the preceding snapshot).

Finally, auditory and visual information blend when sound is made into an image. Musical notation is a great example, and you can see the development of such notations from antiquity, to our times in the image below.