Brain effects are communicative goods. A recent study found common effects among reading and seeing actions:
Participants observed actions and read phrases relating to foot, hand, or mouth actions. In the premotor cortex of the left hemisphere, a clear congruence was found between effector-specific activations of visually presented actions and of actions described by literal phrases.
For example, reading the phrase “biting the peach” and seeing a video of a person bite a peach activate a common set of premotor neurons called “mirror neurons.” These neurons also trigger muscular actions such as actually biting a peach.
Consider the economics of activating these neurons. Making sense of text is relatively expensive. Actually executing actions involve the caloric cost of moving bodily mass. Observing actions is probably the cheapest means to activate the common neurons associated with these different sensory circumstances. Perhaps this helps to explains why so many persons spend so much time on couches, watching sports on television.
Past physical experience affects the extent of neural activation. A scholar who has studied this relation noted:
“When we watch a sport, our brain performs an internal simulation of the actions, as if it were sending the same movement instructions to our own body. But for those sports commentators who are ex-athletes, the mirror system is likely to be even more active because their brains may re-enact the moves they once made. This might explain why they get so excited while watching the game!” [supporting scholarly paper (pdf)]
Sense of presence involves attunement to another like oneself. Common experience of physical action heightens sense of presence. Current demand for televised sports probably depends strongly on explicit marketing investment. An interesting challenge might be to try to calculate the implicit marketing value of sports participation.