ou’ll have more of an impulsive behavioral response, instead of a necessarily thoughtful or measured kind of response. (PBS Frontline 2002, p. 3)
Here the fMRI technique that is materialized in the scanned image, starting with photos of facial affect and using the bodies of volunteer subjects, has allowed the introduction of a dual hierarchy in the cerebral management of emotional information, first between adults and adolescents, and then between young girls and young boys.
In order to see this process of translation more clearly, let us review the description of this experiment and try to bring out all the elements involved in the trajectory from the photograph of the facial affect of fear to the production of the scanned image, of which the researchers’ reading and interpretation produces a classification as a function of the age and sex of the subjects in terms of their management of emotional information : nine boys and ten girls who have been predefined as adolescent and whose eyesight and mental health have been tested lie in a scanner and look at black-and-white photographs from the 1970s of Caucasian-type men and women performing the facial affect of fear according to the tension and muscle positioning indicators developed by Ekman and Friesen. By measuring the signal that reflects variations in the quantity of oxygen in the blood as a function of brain activity (the blood-oxygen-level-dependent or BOLD signal) during periods of visualizing photos of the facial affect of fear versus periods of visualizing a white circle, fMRI produces a statistical image by means of a system of digital computation and analysis which represents in colors a difference in the activation of the cerebral regions under study as a function of the age and sex of the individual in the scanner, cerebral regions which previous experiments on animals and humans suffering from brain lesions have established as being pertinent to the management of the emotional information of fear (Killgore, Oki and Yurgelun-Todd 2001).
Now it is easier to see that a scanned image, similarly to a photographic image, maintains an indirect and synthetic relationship with the “real” that necessitates the incorporation and the preliminary solidification of numerous theoretical and technical elements. As regards the production/visualization of differences as a function of age and sex, one can observe that binary categorization by age and by sex is present at all stages of the experiment : adult men and women are represented in the stimulus photographs and young girls and young boys are tested. However, it is only through the translation of the results of the experiment into scanned images that the differences linked to age and sex become scientifically relevant in connection with the management of emotional information. It is the chain of recordings and transcriptions (Latour 2006) of the notions of fear, sex and age that allows their reorganization and reinterpretation in the course of the experimental process, retaining all the while traces of preceding stages in the process of constructing knowledge about cerebral adolescence. For example, the use of male and female models in the production of the photographs of facial affect makes no attempt to account for any difference between men and women in connection with the emotions, but on the contrary, aims to guarantee the universality of those images in the reflection of a reality thought to be universal, i.e. the division of the human genus between males and females. Whereas the distribution between as many girls as boys in the sample of adolescents tested is constitutive of the experimental protocol whose purpose is to detect a differentiation in cerebral activation between teenage girls and boys in an emotional situation. The young guinea pigs are expected to be representative of the behavioral differences demonstrated by epidemiological studies based on classifications of age and sex.
In other words, the scanned image contains and communicates not only visual evidence of a cerebral activation triggered by a sti