One of the very few (perhaps the only) peer-reviewed scholarly studies devoted to investigating the function of evil laughter in popular culture has been recently been penned by Jens Kjeldgaard-Christiansen, who is a doctoral researcher at the School of Communication and Culture, Department of English of Aarhus University, Denmark.
In his new paper for The Journal of Popular Culture, he points out that :
“Evil laughter [thus] functions as an inferential lubricant, the use or nonuse of which is best understood from within the informational economy of individual ﬁctions.”
And concludes :
“At a diegetic level, villains laugh because they are evil; at a tonal or metaﬁctional level, to signal that they are evil. Evil laughter communicates both these things because it signals the perversely inverted gratiﬁcation that villains derive from pondering or performing villainy.”
See: Social Signals and Antisocial Essences: The Function of Evil Laughter in Popular Culture in The Journal of Popular Culture, Volume 51, Issue 5, October 2018.