Puritanical bias refers to the tendency to attribute cause of an undesirable outcome or wrongdoing by an individual to a moral deficiency or lack of self control rather than taking into account the impact of broader societal determinants. An example might be, "These people sit around all day in their apartments on welfare watching TV, but won't take the time to get out and find a job!" In this case, a selection of persons might have existed for some time under dire economic and/or socially oppressive circumstances, but individuals from that selection have been cognitively dis-empowered by these circumstances to decide or act on decisions to obtain a given goal.
Relation to Other Biases
Puritanical bias is similar to correspondence bias - the tendency to infer dispositional characteristics from behaviours resulting entirely from situational factors - in that it relates to the consequences of over-emphasising dispositional factors over situational factors. Puritanical bias also mirrors a broader social psychology phenomenon: fundamental attribution error; that is the tendency for observers to under-emphasise the importance of situational determinants of a behaviour and to over-emphasise the importance of dispositional determinants. All above phenomena relate to the overweighting of dispositional rather than situational factors in explaining behaviour, and are thus related.
Where puritanical bias differentiates itself from the two is in specifically concerning only unpleasant and unwanted behaviours, by explaining them only through negative dispositional characteristics. It is entirely possible for correspondence bias and fundamental attribution error to emerge in the explanation of prosocial and desired behaviours. For example, one may attribute an individual donating to charity to their own selflessness and good will, while the behaviour would be more suitably explained by the vigour and efficacy with which the charity requests donations. This would be an example of fundamental attribution error, as situational factors have been under-emphasised in comparison to dispositional qualities in explaining a seemingly altruistic act. Further, while the moral nature of the behaviours with which correspondence bias concerns itself is unspecified, it is unique in that it only explains behaviours which result entirely from situational determinants. Both puritanical bias and fundamental attribution error are more flexible in their definitions in that they do not specify the degree to which the behaviour in question is determined by environment or disposition, just that in the explanation of the behaviour the dispositional explanations will be overemphasised and situational explanations underemphasised. Therefore, puritanical bias can be thought of as a more specific form of fundamental attribution error pertaining singularly to undesirable behaviours and undesirable dispositional characteristics.
Explanations
Given its similarity to other cognitive biases, puritanical bias can be partially explained through existing explanations of fundamental attribution error and correspondence bias: