logical experimentation — the relationship between theory, visualization, observation and transcription in the construction of scientific facts — is a classic theme in studies on scientific research (Latour and Woolgar  1988, Hacking  1989, Daston and Galison 2007), including studies on functional imaging research (eg. Beaulieu 2002, Dumit 2004). The latter, however, have focused mainly on the scan-image and the interrogation of various experimental tools that aim to produce a cerebral activation of which the scan is the visible trace.
This paper will first address the use of photography as a tool to capture and represent facial expressions of the emotions, and then it will address the scan-image of the emotional adolescent brain. More specifically, following a cultural history and social science approach and using gender studies as a privileged analytical tool, I intend to investigate the process whereby the cognitive neurosciences, using photographic portraits of actors miming emotions, have produced valid stimuli that allow the fMRI visualization of a cerebral differentiation that distinguishes between adolescents and adults on the one hand, and on the other, between young girls and young boys, in the management of emotional information. In effect, the emotional adolescent brain is constructed according to two interlocking hierarchies : if age difference is taken to be the foundational hierarchy, sex difference is both a driving and a moderating factor within that hierarchy. I begin with the history of Ekman and Friesen’s set of Pictures of Facial Affect, setting aside the object of the proof, i.e. the universality of the basic expressions, and looking at the support and tool of the proof, i.e. photography. The purpose of the exercise is to review experiments in the neurosciences of the emotions concerning adolescents. By concentrating on one dimension of the research that was hardly problematized by the researchers, I hope to demonstrate and interrogate the trajectory of the image, whether photographic or scanned, and its incorporation/production of meaning, particularly in terms of gender, in the construction of an adolescent brain characterized by poor emotional control.
The POFA Set : Capturing, Fixing and Representing Emotions with Photography.
The set of Pictures of Facial Affect that Ekman and Friesen developed in the 1970s consists of 110 black-and-white photographic portraits of Caucasian-type men and women performing the facial expression of the six emotions which the authors consider to be universally recognized and expressed : joy, sadness, fear, anger, disgust and surprise. These portraits, whose function is “simply” to emit or to solicit emotions which are useful in the context of experimental protocols in the neurosciences of the emotions, are nevertheless the product of a history in which the polysemy of images in an iterative relationship between photographs and experts and laymen has produced a univocal cliché.
The historian Ruth Leys points out that when Ekman began studying nonverbal behaviors including facial affect in the 1960s, there was a resurgence of interest in the emotions in the field of psychology following years of neglect, as a result of the work of Ekman’s mentor, the psychologist Silvan Tomkins. Leys explains that Tomkins, inspired by the Darwinian theory of evolution and cybernetic developments, proposed a new approach to the study of emotions. He put forward the idea that there is a limited number of basic emotions which evolution has defined as the organism’s universal response to the environment : fear, anger, distress, disgust, interest, shame, joy, surprise and contentment. Tomkins described these basic emotions as “discrete” and “connected” and as emotional programs located in the subcortical region of the brain, whose behavioral response and physiological expression, especially facial affects, are unique to each emotion (Leys 2010, p. 67-68).
Research on the expression and the interpretation of emotions was nevertheless ongoing all through the first half of the twentieth centu