Explaining pain partly relies on recognizing its first-person phenomenology. This implies using a first-person phenomenological method in addition to third-person experimental approaches in the scientific study of pain. I describe what the former approach is and how it can be integrated with the latter. I begin by briefly examining some philosophical issues concerning the use of introspection. I argue that such a first-person method in the study of pain is essential by showing that it has been consistently used together with standard third-person methods. Next, I describe two uses of introspective methods in scientific experiments: subject introspective reports (investigators have intersubjective access), and investigator introspective reports (investigator is subject). I offer examples of both approaches that include studies of second pain summation and its relationship to neural activities, and neuroimaging-psychophysical studies where sensory and emotional qualities of pain are correlated with cortical activity. Integrating phenomenological and experimental approaches in the scientific study of pain will lead to a more thorough explanation of pain.

1. The Observer is the Observed:
Towards Integrating
Pain Phenomenology and
Third-Person Methods
in the Scientific Study of Pain
Simon van Rysewyk
Taiwan National Science Council Postdoctoral Fellow
Taipei Medical University

2. my focus today
a puzzle for pain science about introspection
pain studies in which researcher-subjects use
introspection
experiential method that integrates first and
third-person methods to study pain
Simon van Rysewyk
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3. a seeming puzzle for pain science
1 experiences seem knowable via introspection
2 introspection is subjective
3 science is intersubjective
∴ experiences cannot be a scientific object
(experiential science is not objective)
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4. a seeming puzzle for pain science
like vision, pain has an object of perception
(tissue damage)
unlike vision, pain itself is an experience only
knowable by introspection
‘An unpleasant sensory and emotional
experience associated with actual or potential
tissue damage, or described in terms of such
damage’ (IASP)
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5. a seeming puzzle for pain science
1 pain seems knowable via introspection
2 introspection is subjective
3 science is intersubjective
∴ pain cannot be a scientific object
(pain science is not objective)
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6. the puzzle’s impact on pain science
conclusion false – pain science studies the brain
pain experience and brain activity must be
distinct (cartesian dualism)
pain science studies brain correlates of pain, not
pain itself
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7. dualism is true of pain science
cartesian dualism implies that the subject
matter of pain is brain activity related to pain
pain science is committed to introspection
pain-neuroimaging was established by robust
correlation of neuroimages with pain self-report
cartesian dualism and pain science are
historically consistent
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8. dualism is true of pain science
metaphysical dualism is not convincing
pain science can assert epistemological dualism
and mind-brain identity theory
identity is advantageous: brain activity is
identical to pain without revealing complex
physical features of the brain
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9. two scientific uses of introspection
researcher-subject verbal/written report
non-researcher-subject verbal/written report
intuitive notion of introspection:
inner perception yielding knowledge of
immediate personal states
intersubjectively available to researchers
taken to indicate sensory qualities
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10. researcher-subjects: double pain
first and second pain results from a sudden
noxious stimulus to a distal part of the body
0.5 to 1.5 second delay between the two pains
impulses in thinly myelinated A axons (6–30
meters/sec) travel much faster than those in C
axons (0.5–1.5 meters/sec)
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11. researcher-subjects: double pain
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12. researcher-subjects: double pain
Lewis & Pochin 1938
independently mapped body regions wherein
they introspected double pain
near the elbow but not the lower trunk although
both sites are about the same distance from the
brain
C fibers that supply the trunk have a short
conduction distance to the spinal cord
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13. Lewis & Pochin 1938
C fibers that supply the skin near the elbow have
a long conduction distance
once these C fibers enter the spinal cord, they
synapse on A neurons
differences in peripheral conduction distance
and time mean that double pain can be
discriminated at the elbow but not the trunk
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14. researcher-subjects: double pain
Landau & Bishop 1953
first pain sharp or stinging, well localized, and
brief (A fibers)
second pain diffuse, less well localized, dull,
aching, throbbing, burning (C fibers)
second pain longer lasting than first pain, vague
unpleasantness
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15. researcher-subjects: double pain
1. the results were obtained through
researchers introspecting their own pain
2. observations about specific pain experiences
3. the observations have been integrated into
our knowledge of pain
4. the observations have been replicated in
studies using standard experimental designs
and methods
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16. relating introspection and brain
activity to pain sensation and emotion
Rainville et al. 1997
subjects rated pain sensation intensity and pain
unpleasantness of immersion of the left hand in
a 47° C water bath for 60 s
condition
hypnotic suggestion
1
↑ pain unpleasantness
2
↓ pain unpleasantness
Simon van Rysewyk
sensation
no
change
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17. Rainville et al. 1997
↑ unpleasantness increased magnitudes of
pain-unpleasantness ratings and neural activity
in ACC (area 24)
no change in ACC for ↓ unpleasantness
no change in S1 activity and magnitude ratings
of pain sensation intensity in both conditions
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18. Rainville et al. 1997
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19. Hofbauer et al. 2001
subjects rated pain sensation intensity and pain
unpleasantness of immersion of the left hand in
a 47° C water bath for 60 s
condition hypnotic suggestion unpleasantness
1
↑ sensation intensity
no change
2
↓ sensation intensity
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20. Hofbauer et al. 2001
↑ intensity increased magnitudes of painintensity ratings and neural activity in S1
no change in S1 for ↓ intensity
no change in ACC activity and magnitude ratings
of pain unpleasantness in both conditions
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21. the significance of brain-pain
phenomenology parallels
changes in experience and brain activity cannot
be predicted only by stimulus properties
changes in experience and brain activity can be
explained by analysis of experience and brain
activity
the neural activity sufficient for a given pain
quality of pain does not prove it exists within
one brain region
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22. an experiential approach to pain
Barrell & Barrell 1975, Price & Barrell 1980
experimental tasks
identify common factors
within pain experiences
identify common factor
interrelationships
identify common factorbrain relationships
phase
horizontal (first-person)
‘phenomenal structure’
vertical (third-person)
‘brain structure’
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23. horizontal phase
horizontal phase stages
experimental subjects
1 question and observe
2 describe from a first-person
perspective
researcher-subjects
3 find common factors and their
interrelationships
4 use psychophysical methods to test
generality and functional
relationships between common
factors
Simon van Rysewyk
non-researcher-subjects
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24. horizontal phase
1. questioning and observing
‘What is it like to experience the unpleasantness
of laboratory pain, such as immersion of the
hand in a heated water bath?’
how of pain (sensations, thoughts, feelings)
not why pain occurs (stimulus conditions)
‘passive attention’, ‘being with pain’, immediate
retrospective attention
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25. horizontal phase
2. describing pain from the first-person
verbal/written reports of immediate pain:
‘My hand was immersed in a 47° C water bath
when intense burning and throbbing occurred in
my hand. Feel bothered by this and distressed.
Is it going to get stronger? Concern. Hope my
hand isn't going to be scalded’
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26. horizontal phase
3. finding common factors and interrelationships
‘phenomenological reduction’
‘Is it going to get stronger? Concern. I hope my
hand isn't going to be scalded”
can reduce to
‘I think and feel concern for future consequences
related to this pain’
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27. horizontal phase
‘Feel bothered by this and distressed’
can reduce to
‘I have a feeling of intrusion related to this pain’
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28. horizontal phase
definitional hypotheses: experiential factors
commonly present during a pain-type
functional hypotheses: common factor
interrelationships
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29. horizontal phase
sample definitional hypotheses:
1. an intense burning throbbing sensation in
the hand
2. an experienced intrusion or threat
associated with this sensation
3. a feeling of unpleasantness associated with
this felt intrusion or threat
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30. horizontal phase
when the factors of intrusion or threat are
present, there is a felt sense of pain
felt sense of pain is pain-aversion
pain-aversion seems about felt bodily integrity
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31. horizontal phase
sample functional hypotheses:
1. felt unpleasantness should increase as a
function of experienced intrusion or threat
2. experienced intrusion should increase as a
function of the intensity of burning,
throbbing sensation
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32. horizontal phase
4. applying psychophysical methods
controlled observation of ratings of experiential
factors (pain aversion) or sub-factors (concern)
rating scale methods (ratio scales)
subjects are not researchers
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33. vertical phase
correlate horizontal results with brain activity to
establish possible causal relationships
patterns of cerebral cortical activity that co-vary
with different factors of pain could be identified
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34. future questions
can less well-known introspective methods be
used in the study of pain?
are there experiential and neural similarities and
differences between sub-types of acute and
chronic pain?
can there be a ‘neural signature’ of pain?
Simon van Rysewyk
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