Consciousness in the cradle: on the emergence of infant experience (Part 2)

 April 17, 2026

Box 2. Infant consciousness through a theoretical lens

Although few theories make unambiguous predictions about when consciousness first emerges, it is possible to draw a rough-and-ready distinction between ‘early- onset’ and ‘late-onset’ theories. Here, we consider this point with reference to four influential theories of consciousness: higher-order representation theories (HOTs); the local re-entry theory (LRT), integrated information theory (IIT), and the global workspace theory (GWT).

Traditional HOTs suggest a late onset of consciousness (Figure I), as they require the capacity to make one’s first-order representations the objects of conceptually structured meta-representational states. However, more recent HOTs hold that perceptual consciousness requires only the presence of a non-conceptual generative model of the reliability of first-order representations [117,118], and thus allow that consciousness might emerge significantly before conceptual thought does.

LRT holds that visual experience requires recurrent processing within visual cortex, a process that is central to the formation of integrated visual objects [119]. It appears to be a ‘late-onset’ theory of (visual) consciousness (Figure I), for anatomical evidence suggests that the visual system is unable to support we consider this point with reference to four influential theories of consciousness: higher-order representation theories (HOTs); the local re-entry theory (LRT), integrated information theory (IIT), and the global workspace theory (GWT).

Traditional HOTs suggest a late onset of consciousness (Figure I), as they require the capacity to make one’s first-order representations the objects of conceptually structured meta-representational states. However, more recent HOTs hold that perceptual consciousness requires only the presence of a non-conceptual generative model of the reliability of first-order representations [117,118], and thus allow that consciousness might emerge significantly before conceptual thought does.

LRT holds that visual experience requires recurrent processing within visual cortex, a process that is central to the formation of integrated visual objects [119]. It appears to be a ‘late-onset’ theory of (visual) consciousness (Figure I), for anatomical evidence suggests that the visual system is unable to support recurrent processing prior to 7 months after birth. Furthermore, backwards masking (which requires recurrent processing) is not effective before 7 months of age [120].

In contrast to HOTs and LRT, IIT [121] suggests an early onset of infant consciousness (Figure I). Although the quantity with which IIT identifies consciousness (Max-Φ) cannot be directly measured, findings from a study [122] that measured a reasonable approximation thereof, ’Φ auto-regressive’, implied that consciousness is in place near birth.

It is not entirely clear what GWT [123] predicts with respect to the emergence of consciousness. Recent evidence (see main text) suggests that some kind of parietal/ prefrontal workspace is in place from birth, but whether this workspace qualifies as consciousness-supporting is uncertain, in part because the advocates of GWT have not supplied a precise specification of what constraints a workspace must meet in order to qualify as truly ‘global’.

Although the four theories discussed here differ in significant respects, they converge on the importance of the thalamocortical system for sustaining consciousness, a structure that is widely, although not universally [124], regarded as a prerequisite for consciousness. If it is granted that a functioning thalamocortical system is necessary for consciousness, then an early (i.e., ‘not before’) limit can be set on the emergence of consciousness of around 24–26 weeks gestation.

Figure I. Four perspectives on the emergence of consciousness. Although experts rarely make precise claims about when consciousness begins, here we connect several views [4,5,16,65,125–128] to different developmental periods and theories. The timeline gives the point at which one can make the claim that consciousness has emerged, with some uncertainty, based on a given theory. Abbreviation: EEG, electroencephalography.The cluster-based approach

Rather than adopt a theory-first approach, we suggest that the study of infant consciousness would be better served by adopting a cluster-based approach, in which claims about the ontogenesis of consciousness are addressed by looking at when the various markers of consciousness in adults (and children) first emerge. The cluster-based approach has been applied to questions of consciousness in non-human animals [24] and humans who have sustained severe brain damage [25,26] and there is every reason to think that it might be fruitfully applied to the question of infant consciousness. Although no single marker is likely to provide definitive proof of consciousness (or its absence), we might be justified in moving from a position of agnosticism to one of warranted belief if there is convergence across a variety of markers.

Within the set of markers of consciousness, we can distinguish two-way markers (i.e., those which have high sensitivity and high specificity) from one-way markers (those which have high specificity but low or unknown sensitivity). A marker qualifies as two-way if its presence/absence corresponds with the presence/absence of consciousness and it qualifies as merely one-way if its presence corresponds with the presence of consciousness, but (as far as we know) its absence does not correspond with the absence of consciousness. Because our focus here is on one-way markers, our main conclusions will concern an upper bound on the emergence of consciousness. That said, we view the development of thalamocortical connectivity, generally regarded as necessary for consciousness, as providing a lower bound of 24–26 weeks gestation [2,27] on the emergence of consciousness.

Although many types of markers of consciousness could be considered, we will emphasize neural markers (Box 3). The interrogation of behavior is certainly relevant to the ascription of consciousness in infancy [28], but designing behavioral tasks to probe infant cognition is difficult and the results often allow for diverse interpretations. Historically, estimates of the age of onset of various cognitive processes have reduced considerably as more sensitive tasks have been invented. More fundamentally, motor control is extremely rudimentary in the first few months of infancy [29] and it is entirely possible that consciousness comes on-line before it can be expressed in behavior. An exclusive focus on behavioral markers might therefore provide a misleadingly late picture of when consciousness first emerges.

The case for early emergence

The cluster-based approach

Rather than adopt a theory-first approach, we suggest that the study of infant consciousness would be better served by adopting a cluster-based approach, in which claims about the ontogenesis of consciousness are addressed by looking at when the various markers of consciousness in adults (and children) first emerge. The cluster-based approach has been applied to questions of consciousness in non-human animals [24] and humans who have sustained severe brain damage [25,26] and there is every reason to think that it might be fruitfully applied to the question of infant consciousness. Although no single marker is likely to provide definitive proof of consciousness (or its absence), we might be justified in moving from a position of agnosticism to one of warranted belief if there is convergence across a variety of markers.

Within the set of markers of consciousness, we can distinguish two-way markers (i.e., those which have high sensitivity and high specificity) from one-way markers (those which have high specificity but low or unknown sensitivity). A marker qualifies as two-way if its presence/absence corresponds with the presence/absence of consciousness and it qualifies as merely one-way if its presence corresponds with the presence of consciousness, but (as far as we know) its absence does not correspond with the absence of consciousness. Because our focus here is on one-way markers, our main conclusions will concern an upper bound on the emergence of consciousness. That said, we view the development of thalamocortical connectivity, generally regarded as necessary for consciousness, as providing a lower bound of 24–26 weeks gestation [2,27] on the emergence of consciousness.

Although many types of markers of consciousness could be considered, we will emphasize neural markers (Box 3). The interrogation of behavior is certainly relevant to the ascription of consciousness in infancy [28], but designing behavioral tasks to probe infant cognition is difficult and the results often allow for diverse interpretations. Historically, estimates of the age of onset of various cognitive processes have reduced considerably as more sensitive tasks have been invented. More fundamentally, motor control is extremely rudimentary in the first few months of infancy [29] and it is entirely possible that consciousness comes on-line before it can be expressed in behavior. An exclusive focus on behavioral markers might therefore provide a misleadingly late picture of when consciousness first emerges.

The case for early emergence

Here, we present four lines of evidence supporting an early emergence view (Figure 1). The first line of evidence appeals to data indicating that intrinsic connectivity networks that are correlated with the capacity of consciousness [30–32] are present and active early in development. One of the most prominent of these networks is the default mode network (DMN), so named because the brain defaults to this mode of activity, which includes mind-wandering and self-referential processes [33], in task-free resting states. Although DMN activity is probably not required for con- consciousness [34,35], studies looking at the recovery of consciousness following anesthesia and severe brain damage in adults suggest that consciousness is associated with reciprocal modulation between the activity of the DMN and fronto-parietal networks, in particular, the dorsal attention network (DAN) and the executive control network (ECN) [36,37]. Previous research had failed to find evidence of anything more than a rudimentary DMN in infants [38,39], but a more recent study [40] using a large fMRI dataset of newborn infants (n = 428) found not only that the default mode, dorsal attention, and executive control networks were present as distinct networks shortly after full-term birth (or by term-equivalent age), but that a reciprocal relationship between the DMN and the DAN was also present. This is a striking finding, for it suggests that key features of the neural circuitry associated with consciousness are present at birth (or term-equivalent age for infants born prematurely).Box 3. Neural measures for investigating the emergence of consciousness

Given the unique concerns of infant research, experimenters often choose neural measurement tools that have fast set-up and are robust to motion artifacts. Using electron-cephalography (EEG) [129], neural data can be recorded while the infant rests in the caregiver’s arms and a flexible, geodesic ‘net’ of electrodes can be quickly fitted to an infant’s head [130] (Figure IA). An even faster set-up time can be achieved using
magneto-encephalography (MEG) [75], which simply requires the infant to be positioned toward the sen-sor array, without the additional set-up time demanded by EEG to adjust channel impedances. Furthermore, MEG, unlike EEG, is not distorted by the skull, which, in infants, contains fontanels, leading to uneven smearing of the EEG signal [131]. Some MEG systems can also record fetal brain activity (Figure IB), which is currently not possible using non-invasive EEG. Only a few infant and fetal MEG systems are operational [75], but optically pumped magnetometers (next-generation MEG devices that can be applied in an ad hoc manner to different head shapes using a 3D-printed helmet [105]) will likely make infant data more accessible in coming years.

A third tool is functional near infrared spectroscopy (fNIRS) [132,133], which records hemo-dynamic activity reflecting oxygen usage by the infant brain (Figure IC). Due to the hemo-dynamic response function, fNIRS data lack the very high temporal resolution of MEG/EEG data, but the minimal preparation time of fNIRS makes it attractive for infant re- search, and high-density, fiber-less, portable fNIRS systems are now available for infant research [134]. Like fNIRS, functional magnetic resonance imaging (fMRI) measures hemo-dynamic activity as a proxy for neural activity, but unlike fNIRS, it is capable of imaging infant brain activity with high (<1 cm) spatial resolution (Figure ID). Although infant fMRI experiments are challenged by motion sensitivity and a loud scanner environment, these obstacles are generally overcome by waiting until the infant is sleeping and then recording spontaneous data during sleep, although protocols for recording awake infant fMRI have recently been introduced as well [79,80,135,136]. Such protocols are a useful expansion of the infant researcher’s toolkit, as a scientific consensus regarding infant consciousness will likely require a confluence of evidence from not one but many of the aforementioned tools, as well as infant behavioral data.

Figure I. Examples of techniques for recording brain activity and/or euro-imaging in infants and fetuses.

(A) Infant electroencephalography (EEG) with a geodesic electrode net (laboratory of Shafali Jeste, video still from https://www. youtube.com/watch?v=x6sTJP0dFgg). (B) Fetal magneto-encephalography (MEG) re- corded from a pregnant woman (University Hospital Tübingen). (C) Infant functional near