I haven't looked at reasearch on this stuff for well over a decade but it is a topic I am interested in from a somewhat different perspective. Feel free to stop now if you are just looking for research.

The approach I've found helpful in expanding emotional awarness (and which works for a lot of other things too) is to skip the words and directly relate the emotion to previous memories of people expressing that emotion (ideally where you have more knowledge of the context) and to previous memories of the person who is currently expressing the emotion (independent of the emotion currently being expressed). It is hard to explain but people do this naturally some of the time and the basic idea is to catch yourself doing it and try to do it more.

I think there are a number of aspects of difficulty interperating emotion (some mentioned in the article): emotions can depend on multiple kinds of unknown information (such as specific past experinces with the situation or subject of the situation or general mood or overall strength of emotions generally), the time and subjects contributing to the emotion may not be obvious even if shared (i.e. someone smiling at something you say might be reacting to how you pronounce a particular word rather than what you are saying), and your own emotional reaction to the other person's emotional reaction (which in depends on the same set of things for you) will take place before sufficient evaluation of the other person's emotion and affect how you perceive it (so, for example, your mood can affect the accuracy of your perception of other people's emotions as can how fast you expect a response is needed). OTOH, there tends to be a fair amount of human interaction aimed at clarifying the situation when stronger emotions are expressed.

IMO, there is a continuous spectrum from how we shift attention in the most boring situations to strong emotions. There can be preparation for expression or some movement signals sent even in cases where there is no perceptible movement to express emotion. We call it emotion about at the point when it becomes visible but there is not a clear line or a fundamental difference.

I think the article slightly overstates the learned aspect of emotions in that there are some emotions that are hard wired in various ways (that even babies express in similar ways) but if we predict when they would be triggered we can inhibit them (and potentially respond in a different way).

I don't think the aritcle is accurate that a prediction based perspective of the brain didn't exist when Emotional Intelligence was written. It doesn't take neurology research to figure that one out, although hopefully it is a more popular perspective now. IMO, it is really the key to getting a decent high level sense of how the brain works.

I would love to read an updated Emotional Intelligence. :)

Side note: Beyond the obviously false "triune brain" thing, many neurologist argue against less obviously incorrect word "neocortex". Pierre Gloor discusses this at some length early in The Temporal Lobe and Limbic System noting that the same basic division has long existed in olfactory areas and that the name "neocortex" is incorrect (he uses "isocortex"). I am not aware of a counterargument (other than "neocortex" already being widely used).