“Feel the heat… skips a beat” or the other way around? August 16, 2007Posted by Johan in Emotion, Neuroscience, Social Neuroscience.
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Can’t go with my heart when I can’t feel what’s in it
Red House Painters – Katy Song
The common-sense understanding of emotions and their physical expressions is that the causal arrow goes one way only: if you feel upset, the feeling will cause your cheeks to flush and your heart to beat faster. However, the opposing notion is also possible: we experience physical arousal, and interpret this arousal as emotion. This is referred to as the James-Lange theory, or simply as feedback theory. This alternative idea is not much younger than the common-sense notion – William James was probably the first to propose it, in the 19th century. More recent simulationist accounts such as Damasio’s Somatic Marker Hypothesis could be said to build on this notion.
A story in the news (Washington Post via Gizmodo) seems to offer some anecdotal evidence for the role of physical arousal in the experience of emotion. Peter Houghton had a “ventricular assist device” installed, which is a developed version of the artificial heart. Unlike the more established Pacemaker, the Jarvik 2000 that Houghton had implanted not only paces the heart but moves blood for it, exchanging the familiar thuds with an even mechanical whir (as an aside, the Jarvik 2000 only helps the right ventricle, since the left ventricle is often left unharmed in cardiac illness – in other words, there is a bit of heartbeat left).
While this is impressive in itself as an example of the advances in medicine, the side-effect is what captures attention and perhaps imagination: Houghton claims to experience less emotion. For instance:
[...] he’s become more “coldhearted” — “less sympathetic in some ways.” He just doesn’t feel like he can connect with those close to him. He wishes he could bond with his twin grandsons, for example. “They’re 8, and I don’t want to be bothered to have a reasonable relationship with them and I don’t know why,” he says.
Judging by the Post story, the emotional flatness seems to occur mainly with regards to other people. This is a little surprising since heart rate is considered more of a marker for fear (which is associated with a raised pulse) or interest (which can lower the pulse) than for happiness or attachment. It is possible that these emotions are also affected, but this went unnoticed in a modern world where there are many opportunities to experience emotional attachment, but few to experience genuine fear.
As the Post article is quick to point out, it remains possible that the emotional symptoms are secondary to general depression, brought on by the ordeal of a life-threatening cardiac illness. However, one of the physicians hints at previous reports of these emotional symptoms occurring following implants. I haven’t been able to find any references – feel free to give me a shout if anyone should find some.
Generally speaking, I’m quite open to the idea that the removing one physical marker of emotion (ie, changes in heart rate) could produce a corresponding reduction in the experience of certain emotions. However, the complexity of the deficits in this particular case is perhaps more consistent with depression. The loss of a physical marker should – if the feedback has merit – result in more global deficits in the experience of basic emotions like fear or interest.