[tdeck]

They're clearly a ceremonial artifact, and their reflective surface is used to perform some religious ritual or other, probably related to the sun.

[jareklupinski]

21st century humans had notoriously poor light receptors, so they used these "smart" devices to reflect more sun into their eyes in order to see while hunched over

[fanatic2pope]

Watching cat videos feels a lot like that.

[evilduck]

They indeed were used as part of a mating ritual.

[hnthrow0287345]

"They clearly stare into the black void to make themselves feel better!"