Chapter
Four
Neuroscience
as precentral gyrus; precuneus; intraparietal sulcus; inferior and superior parietal
lobules’ (Bisenius et al., 2015, p. 180), linking the results to Stanislas Dehaene’s
global neuronal workspace theory (see Chapter 5). Having earlier supported such
a broad fronto-parietal network, Koch’s position has switched to a more restricted
‘posterior cortical hot zone’ for consciousness (Koch et al., 2016). But again, no
mention is made of the hard problem or how any of the areas in these impressive
lists actually relate to consciousness beyond correlating with reports of seeing
the visual stimuli.
Another example concerns eye movements and conscious perception. We may
assume that we are usually conscious of whatever our eyes are fixated on, but
Miriam Spering and Marisa Carrasco (2015) present converging evidence that
eye movements and reportable conscious perception are not tightly linked at
all. Rather than being the exception, dissociations between reported experience
and eye movements may be the norm. For example, when watching a magician
pretending to throw a ball in the air, observers’ eye movements do not track
the imagined ball, but remain fixated on the magician’s face whether or not
they experience the illusion. This is presumably because they are watching the
magician’s direction of gaze (Concept 3.1). The authors suggest that the ‘access of
the motor system to visual information that does not reach awareness may help
manage limited bioenergetic resources’ (p. 256). This assumes that consciousness
requires extra energy and is an optional addition to functional perception. And
this of course raises the questions of why consciousness exists at all, and what
difference in the brain (or elsewhere) could make it arise or not.
These examples give a sense of the major methodological and philosophical
questions which underlie all research in this area, but which tend to go unad-
dressed. Reflecting on this state of affairs, Estonian neuroscientists Jaan Aru and
Talis Bachmann (2015, p. 1) suggest that despite all the studies conducted over
the past twenty-five years, ‘it is not clear how much of this research is directly rele-
vant for understanding the neural basis of conscious experience’. Their view is that
‘many studies using various experimental paradigms have relied on the contrast
between trials with and without conscious perception, but [that] this contrast is
not selective for revealing the NCC’, (2015, p. 1) because the processing that is
studied may in reality either precede or follow from conscious experience rather
than directly correlating with it. Along similar lines, Ralph Adolphs, a professor
of psychology, neuroscience, and biology at Caltech, points out that while the
conceptual problem of consciousness (the hard problem) is notoriously baffling,
the methodological problem of consciousness should also not be underrated:
it is very hard to see how the neural correlates of a conscious experience
can be separated from everything that accompanies such a conscious
experience (our own access to it required for reporting it, antecedent
events that make the experience possible, and other events that blur into
constitutive components of consciousness).
(Adolphs, 2015, p. 174)That is, when we think we are studying the correlates of conscious experience,
we might actually be studying the correlates of the correlates of consciousness,
or the correlates of the precursors of consciousness, or the correlates of access to
consciousness . . .
‘it is very hard to
see how the neural
correlates of a
conscious experience
can be separated
from everything that
accompanies such a
conscious experience’(Adolphs, 2015, p. 174)