I commend Morsella et al. for their attempt to come to grips with the most notoriously difficult question in behavioral and brain sciences: What is consciousness? To their credit, the authors offer a specific answer to this question that centers on the resolution of conflict between physical actions. I too have tried to understand mental activity in terms of internal competition (Rosenbaum Reference Rosenbaum2014), but I have some specific questions for Morsella et al.
First, what is the relation of passive frame theory to Pashler's (Reference Pashler1993) classic theory of attention, which places attention at the response selection bottleneck? Pashler's theory and the theory offered here are similar in this respect, though Pashler's theory mainly focuses on the amount of cognitive effort (or number of cognitive resources) that is summoned when responses must be selected, whereas Morsella et al. mainly focus on the qualitative aspects of experience related to response selection. How are the two views similar or different? Is passive frame theory an advance over Pashler's theory? If so, how?
Second, does passive frame theory actually or adequately address the content of consciousness? Although passive frame theory suggests that the need for consciousness is greatest when decisions must be made about skeletal muscle activity, can the authors defend the hypothesis that the contents of consciousness are limited to skeletal-muscle response selection, if indeed that is what they are suggesting? While it is conceivable that imagining oneself engaging in some activity boils down to anticipating the skeletal-muscle movements to be made at the time, the feelings of muscles pulling on bones are not what one typically experiences as one considers alternative action possibilities. To the extent that the contents of consciousness are typically far removed from the muscle sense, except perhaps when the physical demands of the task demand attention (Vallacher & Wegner Reference Vallacher and Wegner1987), does the theory lose some of its power?
Third, is skeletal muscle activation really the defining ingredient for consciousness? Animals without skeletons engage in response selection all of the time. Think of octopuses, which can show learning of spatial layouts (Boal et al. Reference Boal, Dunham, Williams and Hanlon2000), can engage in astonishing feats of mimicry (https://www.youtube.com/watch?v=t-LTWFnGmegdeception), and can learn by observing others (Fiorito & Scotto Reference Fiorito and Scotto1992). Even the sea slug has neural circuitry that supports experience-based response selection (Kandel Reference Kandel2006). These invertebrates don't have skeletal muscles. Does that mean they lack consciousness? Perhaps I am putting too fine a point on the authors' claim that consciousness comes down to the deliberate control of skeletal muscles. Still, that is what they said, so it would be interesting to know what they think about consciousness in animals without striated muscles.
A fourth, more subtle question pertains to the fact that the sensory outcome of a given pattern of muscle activity (skeletal or otherwise) depends on the interplay of the body and the environment and is ultimately decided by the environment. Reaching out with the hand in one direction or the other has little consequence in and of itself but has a big effect if, say, the hand contacts one electoral ballot switch or the other. If the effects of muscle activation are far removed from the muscle activation itself, then the power of the passive frame theory claim seems weakened. Also, it turns out that muscle activations are never all-or-none. Graded activation of muscles, with more or less activation going to some muscles than others, is how the nervous system controls movement and physical stability (Rosenbaum Reference Rosenbaum2010). Even when actors reverse course, switching from one target to another, detailed analysis of the movement trajectories they produce indicates that muscle activations change in a graded, continuous fashion rather than by abruptly turning off some muscles and turning on others (Henis & Flash Reference Henis and Flash1995).
Whether and how these kinds of graded muscle activations or their sensory consequences are represented in consciousness is an open question. Perhaps large-scale categorical differences between perceptual consequences of different actions are actually represented. Is that what Morsella et al. want to claim? If so, how do they think about the reduced need to imagine the perceptual consequences of alternative actions when choices between actions get practiced and become automatic? That is my fourth question: How do the contents of consciousness change with the development of automaticity? How do the authors conceptualize the growth of automaticity in their theory?
I commend Morsella et al. for their attempt to come to grips with the most notoriously difficult question in behavioral and brain sciences: What is consciousness? To their credit, the authors offer a specific answer to this question that centers on the resolution of conflict between physical actions. I too have tried to understand mental activity in terms of internal competition (Rosenbaum Reference Rosenbaum2014), but I have some specific questions for Morsella et al.
First, what is the relation of passive frame theory to Pashler's (Reference Pashler1993) classic theory of attention, which places attention at the response selection bottleneck? Pashler's theory and the theory offered here are similar in this respect, though Pashler's theory mainly focuses on the amount of cognitive effort (or number of cognitive resources) that is summoned when responses must be selected, whereas Morsella et al. mainly focus on the qualitative aspects of experience related to response selection. How are the two views similar or different? Is passive frame theory an advance over Pashler's theory? If so, how?
Second, does passive frame theory actually or adequately address the content of consciousness? Although passive frame theory suggests that the need for consciousness is greatest when decisions must be made about skeletal muscle activity, can the authors defend the hypothesis that the contents of consciousness are limited to skeletal-muscle response selection, if indeed that is what they are suggesting? While it is conceivable that imagining oneself engaging in some activity boils down to anticipating the skeletal-muscle movements to be made at the time, the feelings of muscles pulling on bones are not what one typically experiences as one considers alternative action possibilities. To the extent that the contents of consciousness are typically far removed from the muscle sense, except perhaps when the physical demands of the task demand attention (Vallacher & Wegner Reference Vallacher and Wegner1987), does the theory lose some of its power?
Third, is skeletal muscle activation really the defining ingredient for consciousness? Animals without skeletons engage in response selection all of the time. Think of octopuses, which can show learning of spatial layouts (Boal et al. Reference Boal, Dunham, Williams and Hanlon2000), can engage in astonishing feats of mimicry (https://www.youtube.com/watch?v=t-LTWFnGmegdeception), and can learn by observing others (Fiorito & Scotto Reference Fiorito and Scotto1992). Even the sea slug has neural circuitry that supports experience-based response selection (Kandel Reference Kandel2006). These invertebrates don't have skeletal muscles. Does that mean they lack consciousness? Perhaps I am putting too fine a point on the authors' claim that consciousness comes down to the deliberate control of skeletal muscles. Still, that is what they said, so it would be interesting to know what they think about consciousness in animals without striated muscles.
A fourth, more subtle question pertains to the fact that the sensory outcome of a given pattern of muscle activity (skeletal or otherwise) depends on the interplay of the body and the environment and is ultimately decided by the environment. Reaching out with the hand in one direction or the other has little consequence in and of itself but has a big effect if, say, the hand contacts one electoral ballot switch or the other. If the effects of muscle activation are far removed from the muscle activation itself, then the power of the passive frame theory claim seems weakened. Also, it turns out that muscle activations are never all-or-none. Graded activation of muscles, with more or less activation going to some muscles than others, is how the nervous system controls movement and physical stability (Rosenbaum Reference Rosenbaum2010). Even when actors reverse course, switching from one target to another, detailed analysis of the movement trajectories they produce indicates that muscle activations change in a graded, continuous fashion rather than by abruptly turning off some muscles and turning on others (Henis & Flash Reference Henis and Flash1995).
Whether and how these kinds of graded muscle activations or their sensory consequences are represented in consciousness is an open question. Perhaps large-scale categorical differences between perceptual consequences of different actions are actually represented. Is that what Morsella et al. want to claim? If so, how do they think about the reduced need to imagine the perceptual consequences of alternative actions when choices between actions get practiced and become automatic? That is my fourth question: How do the contents of consciousness change with the development of automaticity? How do the authors conceptualize the growth of automaticity in their theory?