Well, behavioral economically, anyway.
What are emotions? Emotions are reactions to changes, both past, present, and future, with the ultimate implicit goals of enhancing inclusive fitness, or at least defend adaptive homeostasis. The latter refers to preventing a worsening of the situation for an organism capable of emotional responses, with respect to resource intake.
How many emotions are there? Well, I personally identify eight, including anger, joy, laughter, sadness, fear/anxiety, guilt, shame, and disgust. I'll break each of these down one at a time.
Anger involves a violation of expectations coupled with a loss. Since expectations determine behavioral investment, any violation thereof necessarily entails a loss. Also, obviously, it means that relevant expectations were unrealistic. I will write more on expectations, which involves learning theory in a later post. The exemplar experimental reference interpreted as resulting in this model can be found here.
So, the severity of an anger response is in some proportion to the subjective value of the unrewarded behavioral investment, with subjective value outlined here and here. As well-established concept demands, anger can be "pent up", as can any reinforcing behavior in which expression is restricted.
The purpose of anger is to motivate the punishment of social wrongs, to prevent their reoccurance. Displays of angry violence toward inanimate targets represents an evolutionary overhang, or a behavior adaptive in prehistoric environments, but not modern ones. More specifically, there were far fewer opportunities for the inanimate to violate expectations for most of our prehistory. The angrier one is, the more implicit memory is dominates over the explicit, at the expense of target discrimination. Hence, violent attacks on soda machines, for example.
Another example of target indiscriminance is the typical, often externally unheard, verbal assaults on inconsiderate drivers. This is obviously a wasteful activity even when heard by the offending driver, as in urban environments, strangers are unlikely to be encountered twice. The benefit of adaptive punishment is lost.
This social sensitivity with respect to strangers is due to the way we lived for most of our 200,000 or so years as a species. There was presumably less mobility, sans modern travel techology, so strangers were probably far less frequently encountered and those met were likely to be dealt with for many years. Punishment made sense.
To move on, joy is the flipside of anger. It involves an unexpected gain. Hence, the socially rewarding expression is displayed with an energy in some proportion to the newly realized "surplus" in overall intake of reward(lifted mood). This serves the purpose of reinforcing the behavior of others that enhance inclusive fitness. For evidence of increased motivation after unexpected reward, look here.
Now with laughter, there is merely a violation of expectations. There is no net gain or loss associated, although the magnitude of the novelty factor can mean that a laughter response is merely the dominate among those of competing emotions.
The presumed benefit is in the social signal that there was no gain or loss associated with violated expectations. To illustrate in everyday terms, laughter sends an important social signal when it comes from the listener of a joke that could be taken offensively. There is also the case in the situation in which a cared loved one unexpectedly falls down. There is laughter in absence of perceived injury, to the inverse degree of preceived severity. There is otherwise concern, which is a signal of social value. Similarly, when unexpected falls occur during a comedic performance, laughter ensues given the unlikelihood of injury. Finally, cruel laughter sends the signal that the suffering of another isn't valued.
This conception of laughter was original to me, but not within the field of behavioral research(1). The concept may have originated with the philosopher Kant.
Now, sadness is elicited when there is a past(currently experienced), current, or future unavoidable loss. This represents a "shortage" with respect to required intake of resources. The expression of sadness, including crying, elicits sympathy and help from social allies to get needs met that may otherwise go unmet.
I offer that the relative reluctance of men to cry could have to do with mate competition, but also social alliance against physical threats, and toward gainful physical cooperation. In short, crying can be a sign of social weakness in men. Women, on the other hand, are more likely to form mutually supportive networks with less physical competition and obviously more cooperation. Children cty more than adults, due to the relative inability to meet their own needs, when not used as a manipulative ploy.
Fear and anxiety involve expected losses that are perceived possibly avoidable. Possible losses often took the form of physical threats from both animal preditors and conspecifics(other people) in our extensive prehistory. One implication is that the fear of predation underlies sleep difficulties for the anxious, including lighter sleep and of shorter duration. The presumed advantage is in the ability to rapidly ramp up physical arousal against night preditors. Thus, those with sleep panic attacks often leap out of bed and land on their feed with fists clenched before they even realize what has happened. Anxious insomniacs are often frequently occupied thinking of various ways of avoiding potential losses.
In the modern context, the levels of fear and anxiety experienced, as well as the nature of the triggers, are often inappropriate. One can take the example of the fear of loss of face when getting anxious around srangers, in absence of any long term social consequences in most cases.
Guilt as I conceive it is simply an opportunity cost, with respect to actions taken or forgone. It is felt when a loss to oneself, or to others that are perceived to enhance adaptive fitness is realized. Regret is very much related.
Shame occurs in proportion to a social loss of face. It sends the social signal that the disapproval of one's actions matters to the offending person. It can also signal an understanding of the nature of the offense. Shame is very much like embarrassment, but the latter does not involve a perceived loss of face, at least intitially. It is pre-consequential evaluation.
Quickly, disgust is a response stimuli(anything that our sensse can detect) associated with either harmful germs and/or toxic substances. The gag reflex is one of the allied reflexes that serves the purpose of ejecting harmful material in the process of consumption. Associated differentiated facial expressions send social warning signals on the points above. Naturally, disgust motivates the avoidance of noxious material.
Now, as a general note, as alluded to in the paragraphs on laughter, emotions can compete for simultaneous expression. The screaming demons model very much applies here, which is general feature of competing behaviors, including thoughts. This means that essentially, two or more emotions can be triggered at more or less the same time, with the experience and expression there of a difference between that of the greatest magnitude and that of the next greatest. Competing emotional responses can decay at differential rates, largely depending on the frequency of repeated , but varying triggers as a result of continued evaluation and influx of new information.
Hence, there can be net laughter, or net anger. It is commonly observed that laughter can often follow anger.
This can happen when the associated loss fades, perhaps due to compensatory gains. In that case, the importance of the mere novelty of the outcome becomes dominant, leading to net laughter.
Likewise, anxiety can be increasingly replaced with fear as an unexpected loss is perceived as increasingly unavoidable. Joy can become anger, as when what one thinks is a good deal on a car intially, later is found to be relatively expensive.
I should also mention satiation, which seems to have its own emotional experience and expressions attached, though I wouldn't personally refer to it as an emotion. When satiated, regardless of prior expectations, there tends to be a shift toward lower physiological arousal, as evidenced in a sigh, which presumably brings breathing to a slower rhythm.
As reasoned in my posts on mood linked to in the second paragraph above, mood modulates the magnitude of emotional responses. Lower moods augment negative emotion, and the reverse is true for positive ones.
I hope this post isn't too long, disorganized, or jargon-filled to be enjoyable. I will perhaps offer a simpler post on this subject in the very near future. I will also add more references to this post when time allows.
Update: I've added some references in links above for laughter, as well as the following citation:
1. Nerhardt, G. Humor and inclinations of humor: Emotional reactions to stimuli ofdifferent divergence from a range of expectancy. Scandinavian Journal ofPsychology. 1970, 11, 185-195.
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