Why the Wilhelm Scream, One of the Most Well-Known “Easter Egg” Sound Effects in Video Games, is Used, and How to Test Participants’ Extent of Assessment by Using a Bayesian Statistical Approach

The Wilhelm Scream is the sound effect that first appeared in 1951 and has been used in an almost uncountable number of movies and video games as an “Easter egg” related to pain, injury, and displeasure. The Intensity Paradox theory claims that vocalizations are rated valence-wise with very low accuracy. The learning hypothesis, on the other hand, suggests that repeated exposure allows for overcoming the intensity paradox. To test this, we collected a large sample of two ratings each by 902 raters and developed a novel statistical approach, based on Bayesian statistics, in which we determine the maximum-likelihood probability of Beta distributions of these responses. We asked our participants to rate the Wilhelm Scream mixed in with the other high-intensity vocalizations. The outcome showed an unexpected result—an extremely high precision of rating and consistency in repeated exposure. Furthermore, older men (but not women) rated with lower consistency. This provides, using a natural experiment, novel support for the learning effect of vocalization and the importance of using Easter eggs as a vehicle of familiarity related to gaming attractiveness and audiovisual media creation.