I'm speaking out of experience here, because I haven't experienced much in the way of dualization, but I'd imagine (from a theoretical standpoint) that exposure to a dual actually allows you to
specialize more in your Ego functions. The presence of a dual satisfies your super-id needs, giving you the ability to deal more exclusively in the realm of your Ego.
Mental energy is a limited resource. We may not use all of it all the time, but there is a limit to what can be used. If everyone could allocate this mental energy efficiently across all types of information, everyone would have very similar personalities, discounting behaviorally developed traits. But the socionic model predicts that we can use our Ego and Id functions at a lower marginal cost* than the Supers. The "valued" blocks could be described as functions for which we have a high marginal utility.*
For example, an LSE produces
,
,
, and
very easily, but has to sacrifice a lot of one of those to produce just a little
,
,
, or
. Since the LSE has a high marginal utility for
and
, he has to give up a lot of his other functions to use that kind of information, or remain unsatisfied. When an EII comes along, the LSE can specialize in producing what he is good at and likes (
,
), and leave it to the EII to produce what he is not good at and likes (
,
), and vice-versa for the EII. With both individuals now producing information in their respective areas of efficiency, they have become more productive and well-rounded
as a pair.
*
Marginal cost in this case represents the amount of energy it takes to divert your thoughts to another information aspect. A more technical definition is the amount of resources it takes to produce an additional unit of output.
*
Marginal utility is the additional amount of usefulness or benefit derived from consuming one more unit of a resource.