One example of an ‘imperfect cognition’ which I investigated in a recent paper, is stubbornness. I outlined the similarities and differences between stubborn belief and self-deception. Both being stubborn in holding to a certain belief, and being self-deceived in believing something, seem to be examples of motivationally biased belief. Both can involve very similar behaviours, such as ignoring, dismissing, downplaying, or explaining away unwelcome evidence, and searching one-sidedly for welcome evidence or considerations. In fact, I argue that cases of stubborn belief satisfy the set of sufficient conditions which Alfred Mele (2001) gives for self-deception, and should prompt an amendment of those conditions.
As I see it, stubbornness differs from self-deception primarily in the sort of desires and emotions which are causing the biased behaviour and belief. In standard cases of self-deception, the subject has a desire specifically for the proposition which she falsely beliefs to be true (e.g. she believes her son is not bullying other kids in school, because she desires that her son is not bullying other kids in school). In cases of stubbornness however, the subject’s bias is motivated by a more general sort of desire which is not linked to the content of the false belief.
Stubbornness, for instance, may be motivated by a general aversion to losing arguments, or a desire not to be shown up as being wrong or foolish, or an aversion to having one’s long-standing beliefs threatened, beliefs which give one a sense of comfort and certainty. These sorts of affective factors can cause one to have biased beliefs with various different contents (and thus they can explain stubbornness as a trait, as well as particular occasions of stubbornness). Paradigmatically, people who stubbornly believe that P do not especially desire that P, while self-deceivers do.
Another recent interest of mine, and perhaps another example of an imperfect cognition, is wilful ignorance, and I hope to do work on the analysis of wilful ignorance and the distinction between it and self-deception. Wilful ignorance has been thought to be a species of self-deception, though I would argue that they are independent phenomena.