When you experience the emotion of sadness, there will be changes in facial expression, and your body will be closed in, withdrawn. There are also changes in your heart, your guts: they slow down. And there are hormonal changes.

It's very interesting to think about the distinction with mind, which I just made in very general terms, but it can be made more profound when we think that there are many species, many creatures on earth that are very likely to have a mind, but are very unlikely to have a consciousness in the sense that you and I have.

We do not merely perceive objects and hold thoughts in our minds: all our perceptions and thought processes are felt. All have a distinctive component that announces an unequivocal link between images and the existence of life in our organism.

Emotions are enmeshed in the neural networks of reason.

The emotion is the execution of a very complex program of actions. Some actions that are actually movements, like movement that you can do, change your face for example, in fear, or movements that are internal, that happen in your heart or in your gut, and movements that are actually not muscular movements, but rather, releases of molecules.

The mechanism of primary emotions does not describe the full range of emotional behaviors. They are, to be sure, the basic mechanism. However, I believe that in terms of an individual's development they are followed by mechanisms of secondary emotions, which occur once we begin experiencing feelings and forming systematic connections between categories of objects and situations, on the one hand, and primary emotions, on the other.

We may smile and the dog may wag the tail, but in essence, we have a set program and those programs are similar across individuals in the species.