[PS-2.15] Neuro-computational Laughter Study

Alonso, M. F. 1 , Loste, P. 1, 2 & Marijuán , P. 1, 2

1 Grupo de Bioinformación y Biología de Sistemas
2 Instituto Aragonés de Ciencias de la Salud

Laugh is a human mechanism whose development has evolved to communicate emotions and environment information. It is a social play of instinctive, contagious, stereotyped, unconsciously and controlled vocalizations. Notwithstanding the ubiquitous role of laughter in vocal human communication, its scientific study is relatively young. The link between different classes of laughter and emotional conditions of individuals has not been clearly established yet. There is also a lack of research about emotional patterns in spontaneous laughing sounds, which could provide keys to a subsequent classification. There are no studies in psychiatry attempting the use of laughter as a diagnostic tool either.
The goal of this project is to neuro-computationally explore features which can be detected unambiguously in the sonograms of laughter as bona fide correlates of emotional states and/or pathological conditions.
Several record sessions were performed with visual stimulation in groups of four to six participants. Also an internet videos compilation was made. Each laugh was isolated and catalogued in accordance with the appearance situation. Due to the variety of acoustic characteristics of laughter episodes, and its unique structural features, our study has not only measured and analysed spectral parameters, that is, fundamental frequency and first three formants. We also extract from laughter bouts nine temporal and acoustic variables, in order to establish better methods in pattern classification. These are number of bouts, voiced percentage, bout duration, mean energy, mean entropy, standard deviation of fundamental frequency, jitter, shimmer and harmonic to noise ratio.
In spite of the variability of acoustical parameters, it was observed apparent differences witch might be associated to the laugh types. It would be interesting to contrast these outcomes with the human perception.