Disorders of Volition

an ascending and cognitively continuous development from the simple portrayal of body-centered subject–object relations to full-blown self–other modeling becomes conceivable. More about this in section 2.4. 2.3 The Case of Akinetic Mutism: Is the Volitional PMIR a Functionally Distinct Representational Module? Bilateral anterior damage to the cingulate and bilateral medial parietal damage lead to a situation which can be described by, first, the absence of the PMIR, while, secondly, a coherent conscious model of the world centered by a phenomenal self is still retained. To give a prominent example, Antonio Damasio has introduced a widely known conceptual distinction, which is simple and straightforward: Patients suffering from such damage exhibit wakefulness, but not what he calls “core consciousness.” Core consciousness is the minimal form of phenomenal experience constituted by what he calls a “second-order mapping” and what, for the purposes of this chapter, simply is the basic phenomenal model of the intentionality relation in terms of the representationalist analysis here proposed. Let us look at how Damasio describes such cases: Just as is the case with patients with bilateral cingulate damage, patients with bilateral medial parietal damage are awake in the usual sense of the term: their eyes can be open, and their muscles have proper tone; they can sit or even walk with assistance; but they will not look at you or at any object with any semblance of intention [emphasis mine]; and their eyes may stare vacantly or orient toward objects with no discernable motive. These patients cannot help themselves. They volunteer nothing about their situation and they fail to respond to virtually all the examiner’s requests. Attempts to engage them in conversation are rarely successful, the results being erratic at best. We can coax them into looking briefly at an object, but the request will not engender anything else in terms of productive reaction. These patients react no differently to friends and family than they do to physicians and nurses. The notion of Zombie-like behavior could perfectly well have come from the description of these patients, although it did not. (Damasio 1999, p. 263) This well-documented condition is akinetic mutism (AM), the absence of volition following ventromedial damage or the bilateral anterior lesions of the cingulate just mentioned. A number of diverging etiologies exist. AM is a silent immobility, with the only behavioral manifestation being gaze following related to the examiner’s movements and, in some cases, monosyllabic speech (for three further cases studies, plus a brief review of the literature, see Ure et al. 1998). What we learn from disorders of volition such as AM is how phenomenal volition can deviate in two directions. There is hypervolitionalism, as, for instance, in obsessive–compulsive disorder. There are also hypovolitional states, in which the ability to generate the experience of conscious will is greatly diminished. AM belongs to the second class, as it is a state of wakefulness, combined with the absence of speech, emo32 T. Metzinger