174 9 General Intelligence in the Everyday Human World The Second Brain . The gastrointestinal neural net contains millions of neurons and is capable of operating inde- pendently of the brain. It modulates stress response and other aspects of emotion and motivation based on experience — resulting in so-called "gut feelings" [Ger99]. The Heart’s Neural Network . The heart has its own neural network, which modulates stress response, energy level and relaxation/excitement (factors key to motivation and emotion) based on experience [Arm(4]. Pattern Recognition and Memory in the Liver . The liver is a complex pattern recognition system, adapting via experience to better identify toxins [C06]. Like the heart, it seems to store some episodic memories as well, resulting in liver transplant recipients sometimes acquiring the tastes in music or sports of the donor [EMC12]. Immune Intelligence . The immune network is a highly complex, adaptive self-organizing system, which ongoingly solves the learning problem of identifying antigens and distinguishing them from the body system [P86]. As immune function is highly energetically costly, stress response involves subtle modulation of the energy allocation to immune function, which involves communication between neural and immune networks. The Endocrine System: A Key Bridge Between Mind and Body . The endocrine (hormonal) system regulates (and is related by) emotion, thus guiding all aspects of intelligence (due to the close connection of emotion and motivation) [PH12]. Breathing Guides Thinking . As oxygenation of the brain plays a key role in the spread of neural activity, the flow of breath is a key driver of cognition. Forced alternate nostril breathing has been shown to significantly affect cognition via balancing activity of the two brain hemispheres [SKBB91]. Much remains unknown, and the totality of feedback loops between the human cognitive cortex and the various specialized intelligences operative throughout the