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you experience the emotion of sadness, there will be changes in facial expression, and your body will be closed in, withdrawn.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.

I think it's possible to a certain extent to make those comparisons. The problem is the detail with which the comparison can be made. Of course, the first place to make such a comparison would be to ask for a testimony from different people and have people report on what they experience.

All of that is constantly operating when you not only learn, but when you recall. But as you recall in a different light, the weights with which something is more probably going to be or not recalled on the next instance, are going to be changed. So you're constantly changing the way, for instance, synapses are going to fire very easily or not so easily.

I believe that it is made out of the same cloth of mind, but it is an add-on, it was something that was specialized to create what we call the self. And it exists for very special purposes and it has very special, and I think by and large good consequences, although not only good consequences.

If something produces an undue amount of pleasure or undue amount of displeasure, it's going to be judged differently and it's going to be introduced in your narrative with a different size, with a different development. So that is the next element to superimpose on the sequencing element. And in fact, that element is so powerful that very often it can trump the sequencing event, that the sequencing aspect.

Leaving out appraisal also would render the biological description of the phenomena of emotion vulnerable to the caricature that emotions without an appraisal phase are meaningless events. It would be more difficult to see how beautiful and amazingly intelligent emotions can be, and how powerfully they can solve problems for us.

For pure joy, I look at a small painting by Arbit Blatas. An ocean liner is at the center of the composition, perhaps ready to depart. It holds the promise of discovery.