The psychology of Mona Lisa's smile

Abstract

Mona Lisa's ambiguous expression, oscillating between melancholy and contentment, has captivated viewers for centuries, prompting diverse explanations. This article proposes a novel interpretation grounded in the psychological theory of perceptual organisation. Central to the investigation is the "Ambiguity-Nuance", a subtly shaded, blended region framing the upper part of the lips, hypothesised to influence perceived expression due to perceptual organization. Through carefully crafted artwork and systematic manipulations of Mona Lisa reproductions, experiments reveal how alterations in the perceptual relationships of the Ambiguity-Nuance yield significant shifts in perceived expression, explaining why Mona Lisa's appearance changes and under which conditions she looks content versus melancholic based on perceptual organization. These findings underscore the pivotal role of psychological principles in shaping ambiguous expressions in the Mona Lisa, and extend to other Leonardo's portraits, namely La Bella Principessa and Scapigliata. This study sheds light on the intersection of psychology and art, offering new perspectives on timeless masterpieces.

Keywords: Ambiguity-Nuance; Facial expression; Mona Lisa; Perceptual organisation.

Figure 1

Mona Lisa (1503–1506), Louvre. Source: https://www.wikiart.org.

Figure 2

(Left) La Bella Principessa (1495–1496, private collection); (Right) Young Woman with Tousled Hair or Scapigliata (1508, Galleria Nazionale, Parma). Source: https://www.wikiart.org.

Figure 3

Representation of stimuli used in Experiment 1 under the condition with the line. The first row shows the experimental portraits, and the second row shows the matching controls. Source: Mona Lisa, Bella Principessa, Scapigliata and Maddolena, adapted from https://www.wikiart.org. Young Woman and Elaborate Coiffure, adapted from https:/wikipedia.org.

Figure 4

Representation of stimuli used in Experiment 2 under the condition Ambiguity-Nuance below the corners of the mouth. Source: adapted from https://www.wikiart.org.

Figure 5

Medians (black dots) and Highest Density Intervals (HDI, horizontal grey bars) of the estimated differences between the two distances obtained for experiment 1 (left) and experiment 2 (right). The HDI bars that include zero (crossed by the vertical red dashed line) signify that contentment is practically the same in the Close and Far conditions.

Figure 6

Medians (black dots) and Highest Density Intervals (HDI, horizontal grey bars, see note 5) of the difference in contentment between the above and below Ambiguity-Nuance conditions from close.

Figure 7

Representation of stimuli and labels used in the project. Source: Mona Lisa, Bella Principessa, Scapigliata and Maddolena: https://www.wikiart.org. Young Woman and Elaborate Coiffure: https:/wikipedia.org.