Since the late 1800s, scientists have been stumped over small pieces of stone found buried in India and Pakistan, each carved with a line of symbols over a depiction of an animal—all evidence of the since-IDed Indus Valley Civilization, said to be the oldest Indian civilization known to exist. But although scientists have had nearly 150 years to decipher these tiny "seals," Mallory Locklear explains for the Verge how the markings that appear on the artifacts have yet to be figured out, and how complex statistical techniques and cognitive science are finally bringing researchers closer to cracking the code. It's been a linguistic-linked mystery muddled by the fact that decades' worth of digging has turned up little useful info into the civilization's origins, religious beliefs, or even day-to-day routines—all of which could lend insight into the carvings that appear on the seals.
The Indus script is just one of many ancient ones being analyzed worldwide, and Locklear notes the processes used resemble those used in the movie Arrival: "searching for patterns, testing out theories, and lots and lots of trial and error." Complicating things is that there are only a few symbols on each seal to work with. Plus, researchers aren't even sure if these symbols technically represent language or if they're just visual representations of physical things (most are leaning toward language, though there's infighting on this point). Also in play are a need for funding and the region's politics, with various factions wanting to stake claim to Indus roots. What may soon lead to breakthroughs: the use of those sophisticated processes and even an inscription-extraction app researchers hope to soon have on their phones. More on this puzzle at the Verge. (Ten words deciphered from a centuries-old text.)