Prelingual infants perform mental operations that signal levels of awareness beyond phenomenal consciousness and that may be observed or indexed by processes other than those involved in cognitive accessibility. These include: (1) using action selection processes to group stimuli into perceptual categories, thereby laying groundwork for subsequent concept formation; (2) recognizing and responding appropriately to faces and facial expressions of basic emotions and making stable emotion-cognition connections; and (3) exhibiting movements indicative of intentionality, goal-directed behavior, and problem-solving (Slater & Lewis Reference Slater and Lewis2007; cf. Merker Reference Merker2007). These behaviors may reflect the development of different levels or complexities of awareness and offer possibilities of extending current conceptualizations of ways to access phenomenal experience.

Mechanisms of accessibility and levels of awareness

Developmental scientists routinely observe evidence suggesting that prelinguistic infants not only experience objects and events phenomenologically, they respond to them in meaningful ways. They discriminate between animate and inanimate faces (Ellsworth et al. Reference Ellsworth, Muir and Hains1993), familiar and strange persons (Bushnell et al. Reference Bushnell, Sai and Mullin1989), and among a wide variety of objects sufficiently well to place them in categories (Quinn Reference Quinn, Balter and Tamis-LeMonda2006). As well, they respond differentially to others' emotion expressions (Walker-Andrews Reference Walker-Andrews1998), and execute movements to influence persons, objects, and events, and to solve problems (Sommerville & Woodward Reference Sommerville and Woodward2005).

Foundations of concept formation

Through visual tracking and eye movements, young infants have shown that they can parse visual experiences into perceptual groups that subsequently attain conceptual significance. For example, 3-to-4–month-olds presented with visual images of realistic photographs of cats generalize their looking-time responsiveness to subsequently presented novel cats, but use comparison and selection processes to display visual preferences for exemplars from novel categories including birds, dogs, and horses (Eimas & Quinn Reference Eimas and Quinn1994; Oakes & Ribar Reference Oakes and Ribar2005; Quinn et al. Reference Quinn, Eimas and Rosenkrantz1993). Studies demonstrating categorization abilities early in life indicate that infants do not experience objects in the world as undifferentiated, but as separate groups that fall into distinct representations (Quinn & Eimas Reference Quinn, Eimas, Rovee-Collier and Lipsitt1996). These representations may then serve as placeholders for the acquisition of the more abstract and non-obvious information that occurs beyond infancy, through language and more formal learning of semantic categories (Quinn & Eimas Reference Quinn and Eimas1997; 2000). Thus, over time, the perceptual placeholder representation for cats will come to include the information that cats eat tuna, hunt mice, give birth to kittens, have cat DNA, and are labeled as “cats.”

Emotion expression

In mother-infant face-to-face play, young infants display emotion expressions in synchrony with the mother but also periodically take the lead, indicating behavior other than imitation (Stern Reference Stern1974; Tronick Reference Tronick1989). Their behavior in the “still-face” procedure is typically interpreted as an effort to re-engage the mother (Muir & Lee Reference Muir and Lee2003). 2.5-to-9–month-old infants respond differentially and predictably to the mother's discrete emotion expressions (Izard et al. Reference Izard, Fantauzzo, Castle, Haynes, Rayias and Putnam1995; Montague & Walker-Andrews Reference Montague and Walker-Andrews2001). Through their emotion expressions, children without a cerebral cortex also show evidence of access to phenomenal experience (Merker Reference Merker2007).

Body movement/action

Kinematic data have shown that 10-month-old infants reach more rapidly for a ball that they have been encouraged to throw into a basket than for one they have been encouraged to fit into a plastic tube (Claxton et al. Reference Claxton, Keen and McCarty2003). From ages 9 to 19 months, infants show clear developmental changes in target selection and movements that ultimately lead to problem solving (McCarty et al. Reference McCarty, Clifton and Collard1999).

The three foregoing types of data suggest that prelingual infants have emotion- and action-systems that mediate access to contents of phenomenal experience independently, or largely independently, from those involved in cognitive access. Thus young infants (like hydranencephalic children; cf. Merker Reference Merker2007) appear to possess forms of accessibility that may lie outside the pale of Block's “cognitive” criteria.

Independence and interdependence of access modes

Evidence suggestive of accessibility via emotion- and action-systems (in the absence of cognitive accessibility) can be found in adults as well as in children. However, due to maturation and resultantly enriched connections among neural systems, examples of functionally independent access pathways may become rarer with age. In adults, observations of such independence might often require artificially constrained manipulations or incidental brain lesions. Milner and Goodale's (Reference Milner and Goodale1995) work with patient D.F., for example, suggests that dorsal and ventral visual pathways output separately to action and cognitive systems respectively (also see James et al. Reference James, Culham, Humphre, Milner and Goodale2003). When asked to indicate explicitly the orientation of a slot, D.F. (who had a compromised ability to process information via her ventral visual pathway) was unable to do so. However, when asked to insert a card into the slot as if posting a letter, her action was immediate and correct. Examples also abound of situations where emotion processes seem to glean aspects of experience that lie beyond reach of cognitive accessibility. These include emotion's role in decision making (Bechara et al. Reference Bechara, Damasio and Damasio2000) and in the power of emotional stimuli to guide attention even when people cannot report them (Jiang et al. Reference Jiang, Costello, Fang, Huang and He2006).

Recent evidence suggests that contents accessible to the neural systems of emotion can be made available to the systems of cognitive access (e.g., particularly emotional task-irrelevant stimuli appear to gain access to explicit report mechanisms at the expense of non-emotional target stimuli; Arnell et al. Reference Arnell, Killman and Fijavz2007; Most et al. Reference Most, Chun, Widders and Zald2005a). However, the quality and function of the experience change after the emotion-cognition connection (Izard, in press). For example, when people label emotions, there follows an observable activation decrease in neural areas associated with emotional reactivity (Lieberman et al. Reference Lieberman, Eisenberger, Crockett, Tom, Pfeifer and Way2007). Emotion-cognition-action connections and interactions have played a critical role in the evolution and functioning of consciousness and continue to influence the development of higher levels of awareness in ontogeny.

Implications for visual cognition

Evidence of multiple routes for accessing phenomenology might help reframe findings from the visual cognition literature, several of which Block described in making his argument. Rather than casting phenomena such as the attentional blink (Chun & Potter Reference Chun and Potter1995; Raymond et al. Reference Raymond, Shapiro and Arnell1992), inattentional blindness (Mack & Rock Reference Mack and Rock1998; Most et al. Reference Most, Simons, Scholl, Jimenez, Clifford and Chabris2001; Reference Most, Scholl, Clifford and Simons2005b; Simons & Chabris Reference Simons and Chabris1999), and object substitution masking (Di Lollo et al. Reference Di Lollo, Enns and Rensink2000; Reiss & Hoffman Reference Reiss and Hoffman2006; Woodman & Luck Reference Woodman and Luck2003) in terms of a conscious versus unconscious divide, it may be more fruitful to regard them as failures of cognitive access but not necessarily as failures of other types of access. The limitations that constrain cognitive accessibility might not generalize to other forms of accessibility. For example, evidence suggests that whereas people often fail to detect neutral targets during an attentional blink, emotion stimuli are much less susceptible to this effect (except in cases of bilateral amygdala damage; Anderson & Phelps Reference Anderson and Phelps2001).

A different look at accessibility and reportability of levels of awareness

Developmental research potentially allows us to examine a time before connections between cognition-, emotion-, and action-systems are fully formed, thereby providing insights that might not be as readily gleaned from, but which may affect interpretation of, the adult literature (e.g., evidence of separable access systems). The developmental data also have implications for Block's endeavor to pinpoint neural bases of phenomenal experience unadulterated by access mechanisms. His suggestions for ruling out the machinery of cognitive accessibility are important, but ruling out mechanisms involved in accessibility via emotion and action processes may prove even more challenging. Block's ability to construct an empirically based proposition for how phenomenology might overflow cognitive accessibility gives testimony to the burgeoning of cognitive science investigations relevant to this enterprise. Empirical investigations of similar constraints on emotion- and action-accessibility have yet to catch up. We hope that Block's path-making endeavor will kick-start this process.