Origins

phineas wrote:This seems to be the locus of our disagreement. Now, which one is right? Well, both of course - that can happen in psychology, where traits are more like recipes than ingredients. Though both definitions in the Extroversion article are muddled, what attracts me more to the Eysenck definition is the potential for a more mathematical definition, e.g. how many hours/year do you wish to spend socializing on your own initiative with other people simply for the sake of socializing rather than for other purposes such as business, work and unavoidable family obligations? Or, how many friends do you wish to have? If we take a highly simplified version of the Eysenck definition, schizoid and strongly introverted are very close. It would be interesting to study how strongly genetically determined introversion by such a simplified definition would be. I suspect it would be quite strong.

If you simplify by reducing the number of attributes you consider then less of a distinction is made. One extreme end of such an argument is to say that everything is made of atoms and energy so fundamentallay living and inanimate matter are the same. In that case it's an obvious case of reductio ad absurdum, but what one will always have to consider when simplifying is if all relevant distinctions are still made. I think one important thing is missing in the above simplification and that is motivation/ability, the why of socializing or not. If you want to socialize, but feel you can't then you're an avoidant. If you can socialize but choose not to you're "just" an introvert. If you can't socialize and also don't want to you're a schizoid. Obviously this is also a simplification as well as my opinion so not authoritative in any way.

I really don't see why genetics should play a bigger part on one end of the scale than the rest of it, as if there was an introversion+ gene. It's conceivable that there is, but ultimately it's pure speculation.

phineas wrote:In the animal world species are fairly well divided between social and solitary, and no-one questions the genetic theory as the explanation. There is an interesting example in North America in the difference between the wolf and the coyote; the coyote could well be described as a schizoid wolf. The two species are so genetically similar that they can interbreed but seem to do so only because the domestic dog is involved in the mix. Unlike us human schizoids they reproduce and have flourished throughout the continent. Coyotes are smaller than wolves but what distinguishes them as a separate species is their solitary behavior.

The simpler the organism you consider is, the more it is obviously driven by genetics. In mammals, and particularly in predatory mammals, there is also an element of learned behaviour. A cub doesn't know how to hunt or what to hunt. It learns by practising and observing it's elders. A bit speculative perhaps, but I don't think it's too far off. A species of babboons have quite recently started to hunt pink flamingoes in shallow waters at a particular lake in Africa. More and more of the individual babboons are now learning how to do it, but there are still some of them that don't.

A funny thought popped into my head when reading the above. What if schizoids are about to split off from the rest of humanity and become a new species? If we could actually make ourselves reproduce, and only with other schizoids, speciation would eventually happen even if the genetic component is only 50%.

HungryJoe wrote: but what one will always have to consider when simplifying is if all relevant distinctions are still made.

If we retain the claim of the Five factor Model that only five factors describe a personality (roughly speaking) but use my highly simplified definition for extroversion, e.g. the first proposed one - spends many hrs/yr socializing, then we would lose a huge amount of information about any person analyzed by the model. I would prefer a larger number of dimensions that are more simple and unambiguous. It occurs to me that the various descriptions of extroversion are poor definitions but are perhaps informative inasmuch as they reflect correlations, e.g. people who interact more with others are also more impulsive (Eysenck) but I can think of exceptions (such as radicality).

I think one important thing is missing in the above simplification and that is motivation/ability, the why of socializing or not. If you want to socialize, but feel you can't then you're an avoidant. If you can socialize but choose not to you're "just" an introvert. If you can't socialize and also don't want to you're a schizoid. Obviously this is also a simplification as well as my opinion so not authoritative in any way.

Note that both my proposals concern what you wish to do, but if we look at what people actually do we could define a "loner", and the distinction you have made between various loners - avoidant, introvert, and schizoid is to me refreshingly clear and unambiguous compared to various definitions of introversion I've seen, even if we disagree on my claim that schizoid is extreme introversion.

I really don't see why genetics should play a bigger part on one end of the scale than the rest of it, as if there was an introversion+ gene. It's conceivable that there is, but ultimately it's pure speculation.

I claim genetics plays a uniformly important part throughout the spectrum, it's just that extreme introversion is considered more disordered than extreme extroversion.

A funny thought popped into my head when reading the above. What if schizoids are about to split off from the rest of humanity and become a new species? If we could actually make ourselves reproduce, and only with other schizoids, speciation would eventually happen even if the genetic component is only 50%.

That's what coyotes did in Siberia 20,000(?) years ago. They crossed the Bering Land Bridge to North America and then died out in Siberia. I'm sure the wolves thought they were profoundly disordered, but look who's howling with laughter now in North America!