Experience-dependent reshaping of body processing: from perception to clinical implications

Starting from the moment we come into the world, we are compelled to pay large attention to the body and its representation, which can be considered as a set of cognitive structures that have the function of tracing and coding our state (de Vignemont, 2010). However, we cannot consider body aside from its image, which can determine the way we emotionally perceive ourselves and other people as well as the way we experience the world. With a brief look to the body, we can identify a persons’ identity, thus catching distinctive elements such as her age or gender; further, by means of body posture and movements we can understand the affective state of others and appropriately shape our social interaction and communication. Several socially significant cues can be detected and provided through the body, but this thesis principally aims to increase the knowledge about how we perceive gender from bodily features and shape. Specifically, I report on a series of behavioral studies designed to investigate the influence of the visual experience on the detection of gender dimension, considering the contribution of brain networks which may also have a role in the development of mental disorders related to body misperception (i.e. Eating Disorders; ED). In the first chapter, I provide evidence for the interdependence of morphologic and dynamic cues in shaping gender judgment. By manipulating various characteristics of virtual-human body stimuli, the experiment I carried out demonstrates the association between stillness and femininity rating, addressing the evolutionary meaning of sexual selection and the influence of cultural norms (D’Argenio et al., 2020). In the second chapter, I present a study that seeks to define the relative role of parvo- and magnocellular visual streams in the identification of both morphologic and dynamic cues of the body. For these experiments, I used the differential tuning of the two streams to low- (LSF) and high-spatial frequencies (HSF) and I tested how the processing of body gender and postures is affected by filtering images to keep only the LSF or HSF (D’Argenio et al., submitted). The third chapter is dedicated to a series of experiments aimed at understanding how gender perception can be biased by the previous exposure to specific body models. I utilized a visual adaptation paradigm to investigate the mechanisms that drives the observers’ perception to a masculinity or femininity judgement (D’Argenio et al., 2021) and manipulates the spatial frequency content of the bodies in order to account for the contribution of parvo- and magnocellular system in in this process. In conclusion, in the last two chapters, I briefly report the preliminary results emerging from two visual adaptation studies. The first one, which is described in the fourth chapter, explored the role of cortical connections in body gender adaptation by means of Transcranial Magnetic Stimulation (TMS), with the aim to investigate neural correlates of dysfunctional body perception. The second represents the intent to explain, at least partially, body misperception disorders by applying adaptation paradigms to ED clinical population. Results were discussed in the fifth chapter.