View Full Version : Temperament

05-31-17, 01:39 AM
This thread is meant to explore and understand, "temperament" from an scientific evidence based data oriented perspective.

The quote with citations below is meant to guide and promote discussion, but not limited to.

Neuroscientists know much about the brain chemicals that influence RAGE (Guerra et al., 2010; Siegel, 2005). Chemicals that promote RAGE, usually in the presence of other supporting stimuli, are testosterone, Substance P, norepinephrine (NE), glutamate, acetylcholine, and nitric oxide synthases. Many of these influences can be inhibited with drugs. For instance, because brain norepinephrine can facilitate anger, propranolol (which blocks beta-NE receptors) can diminish irritability, but this applies to other kinds of arousal as well. Other chemicals that diminish RAGE are serotonin, as highlighted especially by eltoprazine (a serotonin agonist, sometimes called a serenic drug, that enhances the effects of serotonin), but again this effect is not specific. Serotonin tends to reduce all forms of emotional arousal. The list of RAGE inhibitors goes on and on. Perhaps the most prominent one is gamma-aminobutyric acid (GABA), the universal inhibitory transmitter of the brain. GABA reduces RAGE activity but it also reduces rates of neural firing in a wide range of other brain activities. In other words, GABA also tends to mute every emotion, inhibit epileptic seizures, and it is quite effective in promoting sleep. Thus, just like serotonin, it is not specific to the RAGE system

We only list these chemicals to highlight that every brain system is controlled by multiple chemistries. But as we will see, there appear to some, such as the neuropeptide, Substance P, that do more specifically activate RAGE in certain higher regions of the brain (although in lower regions they promote quite different brain functions, such as nausea). Other neuropeptides such as endogenous opioids (brain morphine-mimics) as well as oxytocin (another brain social-comfort and confidence-building chemical) can also quite effectively quell RAGE. But again, they also do many other things in the brain. All this indicates that neurochemical control of certain emotions may be quite precise at the level of individual brain circuits, but they may also have different effects in other brain systems. This is one reason it has been difficult to design more precise "mind medicines" for psychiatric practice.

Partly because each animal shows characteristic neurochemical strengths and weaknesses, emotional temperaments are bound to vary widely across individuals as well as species. Emotion-based personality scales have been developed for identification of human temperaments (Davis et al., 2003) but these would be more difficult to devise for animals. However, we can usually breed for emotional-trait differences in animals quite easily through selective breeding (i.e., through the application of "behavior genetics" techniques).

We also know that males and females have different sensitivities in practically all emotional systems. Abundant animal research suggests that, in general, females are biologically less prone to anger than males. Differences in circulating sex hormones, even in humans, are at least part of the reason for such gender differences. Testosterone clearly makes males more assertive and aggressive than females. Indeed, when human females are infused with testosterone, they soon become more aggressive and less tolerant of others (Hermans et al., 2008). Because testosterone also promotes male dominance tendencies, it seems to positively influence several forms of aggression.

Of course, the testosterone/aggression link only pertains to physical aggression. There are other ways to be wrathful and other ways to inflict injury, the most egregious of which may be social rejection (MacDonald & Jensen-Campbell, 2011). When people or animals are deprived of love and acceptance, when they are spurned and forced into lower echelons of social hierarchy where they have few rights and fewer pleasures, this is often emotionally damaging. Although social rejection does not inflict immediate physical injury, who is to say that psychological injury is not equally pernicious in the long run? After all, stress can be a killer, and social rejection induces great stress. It seems that females of a species, and certainly females of the human species, are more than capable of inflicting these kinds of emotional and social injuries on others. So although physical injury generally appears to be the domain of males, females are often more adept at meting out more subtle injuries to the psyche rather than to the body, with comparable adverse health implications (Knack et al., 2011). If anyone doubts the aggressive intent of girls, they need only delve into the social politics between girls in any classroom. A key question is whether this tendency reflects differences in the underlying primary-process emotional systems or in the higher cognitive processes that are much more permeable to learning and culture. There is little research on such issues, but we expect that it has more to do with the tertiary processes of the mind rather than with primary ones, which means that social and cultural interventions are bound to be more important than biological ones in many cases of excessive aggression.

-Jaak Panksepp, Lucy Biven, "The Archaeology Of Mind", P 154-156.