The homunculus myth finally put to rest

Apr 20, 2006 12:44 GMT  ·  By

It is common to think that when people observe something there is some part in the brain that centralizes the information and interprets it and that this part is the self. However, Israeli scientists, using fMRI brain scans, have now discovered that when you observe something more intensely you actually observe yourself less - that part in the brain that is responsible for the 'self' feature of our subjective experience turns off when the brain is confronted with demanding sensory tasks.

Rafael Malach and Ilan Goldberg of the Weizmann Institute of Science, who conducted this study, say their findings show that the "observer" function in the brain does not appear to play an active part in the production of our vivid sensory experiences. We don't have the sensory experiences because they are centralized and interpreted by some "homunculus" living in the brain.

"In our study, we compared brain activity patterns produced by a demanding sensory categorization paradigm to those engaged during self-reflective introspection, using similar sensory stimuli," the authors write. "Our results show a complete segregation between the two patterns of activity. Furthermore, regions that showed enhanced activity during introspection underwent a robust inhibition during the demanding perceptual task. The results support the notion that self-related processes are not necessarily engaged during sensory perception and can be actually suppressed."

In other words, the self is a global result of the entire brain activity - it's not localized in some particular part of the brain. The part of the brain involved in self-observation is only one of many features of the brain and the feeling of self is not necessarily linked to it. The authors say that this discovery has significance for understanding the basic nature of consciousness and perception.

This idea, that in order to be conscious of something it isn't necessary to have some observer inside the brain that "looks at" sensory brain areas, has long been advocated by philosophers such as Daniel Dennett, e.g. in Consciousness Explained, but now for the first time it is supported by direct evidence - the actual scanning of what happens in the brain.

Animated Gif credit: Rafael Malach