Researchers in Germany believe they have identified once and for all the emotion encapsulated in Mona Lisa’s enigmatic facial expression. Those averse to ambiguity and soured by sadness will be happy to know that the study determined that the figure in Leonardo da Vinci’s 16th-century portrait “La Gioconda” is happy.

Led by Dr. Jürgen Kornmeier of the University of Freiburg and Dr. Ludger Tebartz van Elst of the University of Freiburg Medical Center, the researchers created eight alternative versions of “La Gioconda” by tweaking the curvature of the figure’s mouth — four in which it appears progressively more frown-like, and four in which it was appears progressively more smiley. Black-and-white images of these eight replicas and the original were shown to 12 test participants 30 times, randomly reshuffled for each showing. The participants were asked to say whether they perceived each of the figures in the nine images to be happy or sad, and how sure of their response they felt. The original, unaltered image was described in 97% of cases as being happy.

The results of the study were revealed in “Mona Lisa is always happy — and only sometimes sad,” an article published Friday in Scientific Reports. “Given the descriptions from art and art history, we thought that the original would be the most ambiguous,” Kornmeier told the AFP. “There may be some ambiguity in another aspect,” Kornmeier added — perhaps referring to the countless theories about the true meaning of Leonardo’s iconic (self?)portrait — but “not ambiguity in the sense of happy versus sad.”