tors moving their face according to the indications produced by the FAST, one observes that they proceed more from a mosaic than from a transfer of the “real” onto paper or screen. They are the final result of a particular arrangement of a number of images that have circulated in the hands of researchers, actors and observers according to a tautological relationship between the proof and the tool of the proof, being transformed into a consensual object whose faculty is to provoke a unique meaning — for example, the exclusive function of a photograph of a facial expression of fear is to evoke fear — independent of the age or sex of the subjects represented or of the observers. By considering their utilization in the context of experiments in the cognitive neurosciences, I will now interrogate their part in the construction of a difference between adolescents and adults, but also between young girls and young boys, in the management of emotional information. In other words, I hope to understand how these purportedly universal emotional stimuli participate, through the visual translation of fMRI, in producing specific characteristics, in this case of age and sex.
From Photography to Scan Image of Adolescent Emotions : A Visual Translation that Produces Age and Sex.
Since 1999, the date of the first experiment to use Ekman and Friesen’s set of photographs of facial expressions, complementary studies have been carried out using such stimuli in the field of research devoted to the adolescent brain (for example, Killgore, Oki and Yurgelun-Todd 2001, Monk et al. 2003, Yang et al. 2003, McClure et al. 2004, Killgore and Yurgelun-Todd 2005, 2006, Yurgelun-Todd and Killgore 2006). According to researchers in the cognitive neurosciences, this work has taken part in the establishment of a neurobiological model of adolescence, postulating that young individuals experience the perceptible effects of a gap in development between the limbic and the prefrontal regions of the brain. The former, implicated in emotional reactions, is already developing by the beginning of the second decade under the effect of pubertal hormones, while the latter, devoted to control of the emotions and long-term planning, does not reach full maturity until the age of 25 (Casey et al. 2008, Ernst and Mueller 2008). This cerebral configuration favors impulsive behaviors regulated by emotional reactions rather than by rational reasoning, which suggests a neurodevelopmental explanation for statistics on so-called risk behaviors during adolescence, for example, drunk driving, unprotected sex, fighting, consumption of psychoactive substances, etc. These behaviors, which have become the focus of major social and political concern, were seen in the United States to be responsible for a 200 % increase in morbidity and mortality during this phase of life (Dahl 2004). Statistics also show that such behaviors concern boys more than girls and that, taking all types of risk behavior into account, boys are three times more likely than girls to die as a result of this kind of situation (Kelley et al. 2004, Eaton et al. 2006). According to a neurodevelopmental logic, it is therefore important in fMRI verification to evaluate the treatment of emotional information not only from the perspective of age but also from that of sex.
My purpose here is not to present an exhaustive review of the various neuroscientific studies of the emotions whose experimental protocol is based on photographs of facial affect, but by developing an example that is pertinent from the perspective of its importance in the field, to question the process of translation between the stimulus photographs and the images produced by fMRI, as well as its productivity in constructing knowledge about adolescents’ management of emotional information. That is why I shall focus on the work of Yurgelun-Todd’s research team which has become a touchstone for this topic in science as well as in the media (cf. PBS Frontline 2002, Wallis, Dell and Park 2004, Sender 2008).
The team’s first results concerning the management o