fivebells .:
How do you go about investigating why an emotion is arising?
As far as I currently see it, the compounding of an 'emotion' arises due to unseen triggers. Those triggers are the way the mind creates/fabricates 'objects' from the entire field of experience to then establish a subjective relationship with. An emotion is a reaction towards the evaluation of an 'object' or 'objects' the mind has fabricated.
An 'object' can be made of any sense contact (sight, sound, taste, touch (surface and within), smell and thought). When no 'objects' are made of sense contact, then the experience is one of non-segregating (no 'objects') awareness, a soup of sensations/sense contact free of 'objects' being fabricated. No mental labels given to floating empty atoms. They do not inherently exist as these 'things' or 'concepts' which are habitually given to compounding phenomena.
If there are no 'objects' being created for the mind, there are no longer any subjective reactions to mentioned 'objects'. Subjective reactions can go through various baseline shifts as one progresses. A tangibly felt sense of 'self', emotions, affect of all kind, being, presence, shadow being, a rumbling reaction within the chest/throat/stomach etc. All subjective reactions establishing a relationship, pleasant, unpleasant or neutral with a conceived 'object'.
Eg. Someone shouts an insult at you. The sound of the words hit the ear door, the sounds become an 'object' for consciousness to land on. The evaluation and thought of 'that is insulting' becomes yet another 'object' for consciousness to land on. An evaluation occurs, name and form, a subjective reaction takes place. Depending on your baseline, a full affective emotion arises to establish a relationship of aversion towards the 'insult' which has become an 'object', or perhaps your baseline has simply a rumbling of tense sensations in the chest arise. This rumbling tension is still a subjective reaction to the 'object' that has been conceived in the mind.
But if one trains the mind bahiya style, seeing in the seen, hearing in the heard, no such 'objects' are created. The words of insult are not 'objectified' to be reacted towards subjectively. They are simply sounds being heard in the heard. A non-fashioning , non-fabricating, no 'objects' equanimity. The ultimate equanimity according to the suttas, that trumps the first two types, equanimity of multiplicity and equanimity purified by 4th jhana , both fabricated and fashioned.
See how the mind fabricates the 'object' , its accompanying 'subjective' reaction and investigate this 'subject/object' relationship rather than just simply developing an equanimous subjective reaction, and one will also see how the cessation of such fabrications of mind comes about.
Note: Even the subjective experience can be made into an 'object' (which ultimately it also is) giving the impression there is no subject anymore. Yet there is still the subject/object (or object/object) reaction taking place. It just becomes 'sticky-free'.
My 2 cents,
Nick