Active areas are sensitive to social influence factors and to the instances of instrumental rationality. These are also the areas where, being involved in the conscious part of the decisional process, it is possible for subjects to exert a systematic activity of planning and control. The elicitation of the desirable characteristics of a potential partner will necessarily stimulate the active areas, in that it concerns a process of rational deliberation. However, as already observed, this does not imply that such abstract considerations actually translate into consistent choice criteria once subjects find themselves in the position of choosing real partners . This latter choice depends, as already discussed, on the interaction between the rewards from the active areas and from the receptive ones, and in the absence of a sufficient level of indirect reward, the stability of the couple is seriously at risk of being compromised.
On the other hand, couples may exist not only because of the intrinsic value of the relationship but also because of its instrumental value
These remarks seem to be supported by the relative prevalence of subcortical structures and processes with respect to neocortical ones in the determination of the choice of the partner . Between the abstract desirability of a partner and the actual formation of a long-term couple bond there is therefore a wide gulf. The formation of a couple bond implies a complex chain of favorable situations and circumstances. Not only do the reciprocal compatibility tests have to be successfully passed, but it is equally necessary for the partners to effectively implement a stable repeated cycle of cooperation, along which each one manages to appropriately feed the other with the needed indirect rewards, and vice versa. It is therefore far from strange or unlikely that a subject ends up forming a couple bond with a partner whose characteristics are different (and in some cases, very much so) than the ones s/he claimed to prefer at an abstract level.