Great question. This can be answered from an internal and external motivation approach. In fact, theories of motivation and learning, such as the ones proposed by George Allport and Howard Gardner, agree that there are two types of motivators. Internal, and external.
Now, let's look at exactly what kind of activities Emily does that would require motivation.
Emily mainly keeps away, refuses to catch up with the time (such as paying taxes in Jefferson), does not update nor fix her house, and has essentially grown into a recluse.
Emily befriends a younger man and goes about town with him, causing the shock and shame of her old-fashion society. She insists on keeping this man, to the point of trapping him. We know what she does with him. She also keeps her servant, mouths off the pastor, and ignores all advice from her cousins when it comes to her relationship with Homer.
Young Adult Age
Emily is finally away from her father's influence and returns to town, changed and looking different. She attempts to re-join society by giving pottery classes. This, however, is short-lived and Emily returns to isolation. This is after her father had died and Emily had refused to give up his body until the police intervened.
Emily lives under the shadow of her forceful and rough father, who isolates her from the rest of the world, as he wanted to keep her for himself. As such, Emily grows without any clue as to how to face the world outside her home.
Internal motivators entail stimulus-reaction behaviors that are either inherited at birth, or taught to us as we grow up.
The events in Emily's life show that her sociopathic behavior is ingrained and inherited from her family. We know that her great aunt had gone insane.
We also know that the family, as a whole, is strange and think of themselves quite better than others. All of this leaves us to conclude that there is a pattern of antisocial behavior among the Griersons, and this is what motivates the strange behaviors of Emily.
It is not so much that she seeks for her psychopathy for motivation, but the mental illness that is so rampant in the family does it on its own. This is the only way the Griersons know how to do things:
1. Encroaching a victim (Dad with Emily, Emily with Tobe, Emily with Homer)
2. Not letting go (Dad with Emily, Emily with Tobe, Emily with Homer, Emily with Dad's dead body)
3. Imposing their will upon others (Emily with Homer, Emily with Jefferson County, Dad with Emily, Dad with Jefferson County, Emily with the Pastor, Emily with her cousins from Alabama).
4. Remaining stagnant throughout time (Dad, Emily, Emily's Aunt Wyatt).
The lack of adjustment skills caused by sociopath tendencies in the family are the primary motivators of all of these absurd behaviors. They also explain why Emily, even when she tries, cannot quite fit into society. This is because the illness in the family can also be a negative motivator, that is, a decelerator of her personality. If the Griersons were mentally stable, their motivation would not stem from a need to control and catch, but from a need to communicate and make meaningful connections.
These are the environmental inputs that match our needs and desires and prompt us to action. In Emily's case, her external motivators were superseded by the internal ones. This is because, in a mind such as Emily's, it is very hard to find something to supplement years of bad upbringing, bad habit formation, and the encouragement of all of the above by a crazy family.
Still Emily was a woman and this is why she actually attempted, albeit without success, to join in the world. Her motivators could have been:
- Fear of loneliness
- Fear of losing her young and femininity
- A desire to feel like a woman (with Homer)
- A desire to break free from the ties that trap them to her family
- A desire to try and catch up
- A genuine want to form human connections through the pottery classes
- An inner challenge to see herself different than what all the Griersons expected.
Since Emily's ending is so chaotic, it is no doubt that the external motivators were, indeed, superseded by the internal ones. This is a shame, but it is actually a realistic view into the lives of people who are both unwilling and unable to shift their paradigms of life. The result is an overall inability to fit in anywhere. Hence, these people end up making their own rules and abiding by their own, strange, realities.