4 Barca et al.
reciprocity with caregivers and peers. Thus, in parallel to the 
negotiation of identity with caregivers (through a relative detach-
ment from them, a renegotiation of intimacy, and the questioning 
of their confirmatory authority), the modifications of friendship 
structures—from childhood to adolescence—lay the ground for 
the progressive recognition of social contexts and peer relation-
ships as the elite territories for the modulation and exploration 
of personal identity. The redefinition that the adolescent has to 
face in these territories of exploration (of the self as an individ-
ual separated from the other and of the self with the other) might 
pass through a phase of reduced coherence in the narration of 
the self and hence an increased level of uncertainty. Coherence 
in the self’s narrative is considered a measure of well-being and 
has been associated with psychopathology in adulthood (Klim-
stra and Denissen 2017) and adolescence (Lind et al. 2020, Shiner 
et al. 2021). For example, narrative incoherence has been found 
to be associated with personality disorders in adolescents (Lind 
et al. 2019), where “identity diffusion” (e.g. feelings of emptiness 
and being fragmented and lack of a sense of continuity over time) 
might be considered an expression of high levels of uncertainty of 
the self.
Emotion-wise, a developmental trend toward an increased
specificity of emotion-related maps of bodily sensations (Barca 
et al. 2023)—a proxy of interoceptive representations of
emotions—has been reported from children aged 6 years to adult-
hood (Hietanen et al. 2016). Pubertal changes encompass dramatic 
bodily and neuroendocrine system changes, comprising—but not 
reduced to—changes in the reproductive, adrenal, and growth 
axes (Cameron 2004). Thus, adolescents might face at least four 
sources of uncertainty: (i) the uncertainty due to physiological 
alterations related to bodily changes and to modification in hor-
monal levels leading to sexual maturity; (ii) the uncertainty in self-
identity (i.e. the structure of self-awareness) and personal identity 
(i.e, the narrative diachronic self) (Drummond 2021), which might 
be coupled with changes in body image and the development of 
gender identity; (iii) the uncertainty in affect regulation, with the 
emergence of new forms of affectivity as feelings of love and sex-
ual attraction toward a partner; and (iv) uncertainty in the social 
context, with respect to their social status and role expectations 
in the adult society. Such high levels of uncertainty might lead 
to a poorly defined sense of self, with unclear boundaries and a 
sense of emptiness. In this context, pain becomes a possible way 
to recover a bodily sense of self, and self-injurious behavior might 
be instantiated as an attempt to reduce the rise in the levels of 
uncertainty in these (and potentially other) domains, toward the 
transition to adulthood (see Miller et al. 2020 for a closely related 
approach on addiction).
Active inference, interoceptive processing, 
and uncertainty reduction
Active inference is based on the idea that in order to engage in 
adaptive allostatic regulation and goal-directed behavior, living 
organisms continuously strive to minimize the surprise of their 
sensations or, more formally, an upper bound to surprise: varia-
tional free energy (Parr et al. 2022). Notably, the (expected) free 
energy minimization processes that drive active inference jointly 
consider two complementary objectives. The former (utilitarian) 
objective is to realize one’s preferences, such as being satiated 
or safe, by minimizing the discrepancy between preferred sensa-
tions (encoded as “priors over observations” in active inference) 
and current sensations in different modalities (e.g. interoceptive 
or exteroceptive). The latter (epistemic) objective is to reduce 
uncertainty about one’s estimated state. This means that active