Persian Bell, Ancient Persia
The term 'bells and whistles' alludes to purely attractive additional features or trimmings. Rather than being superfluous to technological development, bells and whistles are often essential components to the tools they adorn, however.

Bells, such as these Ancient Persian examples, emanate melody through their movement and hence captivate our attention. There is no huge leap of evolutionary transformation between these bells and the continual alerts of our smart phones. Both are designed to gain our attention, to alert us to actively attend to the source of their audible emission.