“…While laughter has received attention from a wide range of researchers-it is present, for instance, in many of Piaget's observations (Piaget, 1945)-systematic studies on laughter development are sparse. There have been studies on laughter phonetics and acoustics in infants (Kret et al, 2021;Sauter et al, 2018) and studies looking at the relationship between child smile and laughter production and several mother characteristics such as personality traits, parenting, and attachment styles (e.g., Bridgett et al, 2013;Malatesta et al, 1989;Washburn et al, 1972). All these studies yield important insights into laughter evolution and the crucial role that laughter has for the development of a baby.…”