In the 1999 movie The Matrix, the mentor Morpheus tells the hero Neo that he has an advantage over his artificial-intelligence enemies because “their strength, and their speed are still based in a world that is built on rules. Because of that, they will never be as strong, or as fast, as you can be” (Wachowski & Wachowski Reference Wachowski and Wachowski1999). The assumption made by the characters in The Matrix and by Morsella et al. in the target article is that consciousness has a purpose, and that purpose is the flexibility of responding to a complex world. Just as Neo can bend the rules that define the virtual reality of the “Matrix,” Morsella et al claim that consciousness allows us to over-ride fixed patterns of behavior, particularly when two or more of these patterns come into conflict. We applaud Morsella et al. for such a large-scale integrative theory on the function and neural basis of consciousness. We agree that there are substantial data that point to a role for conscious processing in flexible responding. However, we assert that a more expansive view of conscious experience must be considered than one that explains only sensation. In particular, we think that internally driven experiences, such as memory retrieval and metacognitive feelings, are critical in understanding consciousness.
Morsella et al. are explicitly interested in one category of conscious experience – namely, sensations. However, a theory of consciousness should consider other types of phenomenological experiences as well, such as propositions, attitudes, volitions, emotions, and feelings (see Kim Reference Kim2010). For example, my hope that person X will be elected President and my belief that the events in The Matrix are not true are certainly conscious experiences, but something quite different from the sensation of green when I look at a tree. In particular, experiences associated with memory represent an important aspect of consciousness. Similar to the arguments made by Morsella et al., many aspects of memory, including the process of retrieval itself, remain opaque to conscious introspection, but the products of retrieval are vividly conscious.
Our claim here is that internal conscious feelings play an important role in conscious experience. That is, internal conscious feelings allow us to respond to error and conflict, just as conscious perception allows us to override automatic responses. Consider internal conscious experiences, such as tip-of-the-tongue states and déjà vu experiences (Schwartz & Cleary Reference Schwartz, Cleary, Dunlosky and Tauber2016). These experiences are certainly conscious, although they derive from internal processing rather than the processing of external stimuli. Indeed, many metacognitive experiences – from confidence in retrieved answers to feelings of warmth about impending problem-solving – are conscious experiences (Kostic et al. Reference Kostic, Booth and Cleary2015; but see Kornell Reference Kornell2014). This is not to say that some forms of metacognition may be implicit and operate at a non-conscious level (see Kornell Reference Kornell2014; Reder Reference Reder1996), but many metacognitive experiences are not just conscious but attention demanding (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011).
Tip-of-the-tongue states are metacognitive experiences associated with difficulty in retrieval from semantic or lexical memory (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011). Neuroimaging data suggest that tip-of-the-tongue states emerge from prefrontal cortex, particularly the dorso-lateral prefrontal cortex and the anterior cingulate (Maril et al. Reference Maril, Wagner and Schacter2001; Reference Maril, Simons, Weaver and Schacter2005). Similarly, other metacognitive experiences also arise in the prefrontal lobe (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). This pattern contrasts with the view of Morsella et al. that the frontal lobe is less involved in conscious experience than other cortical regions. It may be that conscious sensations are a function of activity in cortex other than frontal, but that conscious internally driven experiences, such as tip-of-the-tongue states, derive from activity in the prefrontal regions. If this is so, it would appear unlikely that consciousness is predicated on any one area of the brain.
Similar to the arguments put forth by Morsella et al., we have argued that metacognitive experiences also serve the purpose of error detection – that is, in serving as alerts as discrepancies in the internal cognitive processes that drive memory (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016; Schwartz & Cleary Reference Schwartz, Cleary, Dunlosky and Tauber2016). In tip-of-the-tongue states, the retrieval process has not succeeded, but the metacognitive process indicates that the unretrieved target is stored in memory. The tip-of-the-tongue state drives us to behavior (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011), much as the sensation of pain and heat drive us to put down the hot frying pan as quickly as possible. For example, people in tip-of-the-tongue states are more likely to express curiosity and actively seek out the answers to unretrieved questions than those not in tip-of-the-tongue states (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). Moreover, people in tip-of-the-tongue states are likely to spend more time attempting retrieval than those not in tip-of-the-tongue states (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). Thus, in metacognitive parlance, tip-of-the-tongue states are conscious monitoring experiences that allow us to control an otherwise opaque retrieval process.
Morsella et al. consider sensation as the main source of information as input for consciousness and, consequently, focus on the idea of phenomenal consciousness. In contrast, to use Block's terminology, we assert that they focus instead on access consciousness, that is, those conscious processes that inform action and speech (Block Reference Block and Gazzaniga2009). The input to such decision-making routines need not have phenomenal qualities, so their arguments beg the question as to why we have phenomenal consciousness at all. This problem is potentially resolvable by considering inner states (such as metacognition) as other sources of information for consciousness. These inner states can add subjective feeling to the access consciousness resulting from sensory information (see Koriat Reference Koriat, Zelazo, Moscovitch and Thompson2007).
In conclusion, we agree with Morsella et al. that exploring the function of consciousness will be critical in understanding what it is, how it evolved, and its neural correlates. However, restricting oneself to only one aspect of consciousness runs the risk of not finding the relations between domains of consciousness. Thus, we argue that any theory of consciousness must account for memory and metamemory experiences.
In the 1999 movie The Matrix, the mentor Morpheus tells the hero Neo that he has an advantage over his artificial-intelligence enemies because “their strength, and their speed are still based in a world that is built on rules. Because of that, they will never be as strong, or as fast, as you can be” (Wachowski & Wachowski Reference Wachowski and Wachowski1999). The assumption made by the characters in The Matrix and by Morsella et al. in the target article is that consciousness has a purpose, and that purpose is the flexibility of responding to a complex world. Just as Neo can bend the rules that define the virtual reality of the “Matrix,” Morsella et al claim that consciousness allows us to over-ride fixed patterns of behavior, particularly when two or more of these patterns come into conflict. We applaud Morsella et al. for such a large-scale integrative theory on the function and neural basis of consciousness. We agree that there are substantial data that point to a role for conscious processing in flexible responding. However, we assert that a more expansive view of conscious experience must be considered than one that explains only sensation. In particular, we think that internally driven experiences, such as memory retrieval and metacognitive feelings, are critical in understanding consciousness.
Morsella et al. are explicitly interested in one category of conscious experience – namely, sensations. However, a theory of consciousness should consider other types of phenomenological experiences as well, such as propositions, attitudes, volitions, emotions, and feelings (see Kim Reference Kim2010). For example, my hope that person X will be elected President and my belief that the events in The Matrix are not true are certainly conscious experiences, but something quite different from the sensation of green when I look at a tree. In particular, experiences associated with memory represent an important aspect of consciousness. Similar to the arguments made by Morsella et al., many aspects of memory, including the process of retrieval itself, remain opaque to conscious introspection, but the products of retrieval are vividly conscious.
Our claim here is that internal conscious feelings play an important role in conscious experience. That is, internal conscious feelings allow us to respond to error and conflict, just as conscious perception allows us to override automatic responses. Consider internal conscious experiences, such as tip-of-the-tongue states and déjà vu experiences (Schwartz & Cleary Reference Schwartz, Cleary, Dunlosky and Tauber2016). These experiences are certainly conscious, although they derive from internal processing rather than the processing of external stimuli. Indeed, many metacognitive experiences – from confidence in retrieved answers to feelings of warmth about impending problem-solving – are conscious experiences (Kostic et al. Reference Kostic, Booth and Cleary2015; but see Kornell Reference Kornell2014). This is not to say that some forms of metacognition may be implicit and operate at a non-conscious level (see Kornell Reference Kornell2014; Reder Reference Reder1996), but many metacognitive experiences are not just conscious but attention demanding (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011).
Tip-of-the-tongue states are metacognitive experiences associated with difficulty in retrieval from semantic or lexical memory (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011). Neuroimaging data suggest that tip-of-the-tongue states emerge from prefrontal cortex, particularly the dorso-lateral prefrontal cortex and the anterior cingulate (Maril et al. Reference Maril, Wagner and Schacter2001; Reference Maril, Simons, Weaver and Schacter2005). Similarly, other metacognitive experiences also arise in the prefrontal lobe (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). This pattern contrasts with the view of Morsella et al. that the frontal lobe is less involved in conscious experience than other cortical regions. It may be that conscious sensations are a function of activity in cortex other than frontal, but that conscious internally driven experiences, such as tip-of-the-tongue states, derive from activity in the prefrontal regions. If this is so, it would appear unlikely that consciousness is predicated on any one area of the brain.
Similar to the arguments put forth by Morsella et al., we have argued that metacognitive experiences also serve the purpose of error detection – that is, in serving as alerts as discrepancies in the internal cognitive processes that drive memory (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016; Schwartz & Cleary Reference Schwartz, Cleary, Dunlosky and Tauber2016). In tip-of-the-tongue states, the retrieval process has not succeeded, but the metacognitive process indicates that the unretrieved target is stored in memory. The tip-of-the-tongue state drives us to behavior (Schwartz & Metcalfe Reference Schwartz and Metcalfe2011), much as the sensation of pain and heat drive us to put down the hot frying pan as quickly as possible. For example, people in tip-of-the-tongue states are more likely to express curiosity and actively seek out the answers to unretrieved questions than those not in tip-of-the-tongue states (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). Moreover, people in tip-of-the-tongue states are likely to spend more time attempting retrieval than those not in tip-of-the-tongue states (Metcalfe & Schwartz Reference Metcalfe, Schwartz, Dunlosky and Tauber2016). Thus, in metacognitive parlance, tip-of-the-tongue states are conscious monitoring experiences that allow us to control an otherwise opaque retrieval process.
Morsella et al. consider sensation as the main source of information as input for consciousness and, consequently, focus on the idea of phenomenal consciousness. In contrast, to use Block's terminology, we assert that they focus instead on access consciousness, that is, those conscious processes that inform action and speech (Block Reference Block and Gazzaniga2009). The input to such decision-making routines need not have phenomenal qualities, so their arguments beg the question as to why we have phenomenal consciousness at all. This problem is potentially resolvable by considering inner states (such as metacognition) as other sources of information for consciousness. These inner states can add subjective feeling to the access consciousness resulting from sensory information (see Koriat Reference Koriat, Zelazo, Moscovitch and Thompson2007).
In conclusion, we agree with Morsella et al. that exploring the function of consciousness will be critical in understanding what it is, how it evolved, and its neural correlates. However, restricting oneself to only one aspect of consciousness runs the risk of not finding the relations between domains of consciousness. Thus, we argue that any theory of consciousness must account for memory and metamemory experiences.