Asp et al. Neural correlates of credulity analysis revealed: (1) lesion size as a covariate was not signiﬁcantly related to credulity, and (2) when the patients were ranked on the credulity measure (the total ads together), the top 5 most credu- lous vmPFC patients (M D 28.8, SD D 15.5) actually had a slightly smaller mean lesion size than the bottom 5 least credulous BDC patients (M D 29.6, SD D 23.7). Moreover, an appropriate lesion size measure interpretation must be understood in the context of the region which is damaged. Small lesions to critical struc- tures such as the amygdala, hippocampus, or thalamic nuclei may critically impair a variety of functions, while a similar size lesion to the relatively large and uniform vmPFC may not have simi- lar functional disruptions. Thus, lesion size, per se, while different between the two groups, was unlikely to contribute to the increased credulity and purchase intent in the vmPFC group relative to the BDC group, i.e., the deﬁcit is speciﬁc not to lesion size but to lesion location. Our ﬁndings support the FTT, which posits that the prefrontal cortex is critical in mediating doubt (Asp and Tranel, 2012), and thus damage to the critical ventromedial region of the prefrontal cortex should result in a “doubt deﬁcit.” While it has been noted that ventromedial prefrontal patients are often vulnerable to shady business ventures and snake-oil salesmen (Damasio, 1994), the current study provides the ﬁrst direct evidence beyond anecdotal reports that damage to vmPFC increases credulity. Indeed, this speciﬁc deﬁcit may explain why highly intelligent vmPFC patients can fall victim to seemingly obvious fraud schemes. Warnings from friends and family often go unheeded and vmPFC patients’ sus- ceptibility can result in bankruptcy if they continue to make their own ﬁnancial decisions. Moreover, in the acute phase of recov- ery following vmPFC damage, patients often confabulate and are markedly suggestible (Berlyne, 1972) to other individuals and, on rare occasions, even to the environment around them (Lhermitte, 1986). Taken together, this evidence indicates that the vmPFC is a critical neural structure preventing unwarranted belief toward unscrupulous companies or individuals who try to bilk one’s money. In our study, we gave novel external persuasive information to vmPFC patients and found that they tend to be credulous to that information. However, as suggested in the Introduction, vmPFC patients can also be obstinate and bull-headed toward novel information. Intuitively, it may appear contradictory that an individual can both be credulous and rigidly obstinate to infor- mation. Yet, this is the strange state often exhibited by patients with vmPFC damage. We hypothesize that the critical factor deter- mining the easy acceptance or rigid rejection of information in vmPFC patients is whether the cognitive representation is initially generated by external or internal information. If the cognitive representation is initially generated by external information (as in the present study), it is believed, but then it fails to be falsi- ﬁed by comparisons with extant mental information. Thus, the new information is not doubted, and credulity ensues. If the cognitive representation is initially generated by internal informa- tion, it is believed, but then it fails to be falsiﬁed by comparisons with new external information. Thus, the old information is not doubted, and a pertinacious belief is evinced. This suggests the initial cognition is always ﬁrst believed and it is the comparison and falsiﬁcation to other beliefs that is disrupted. vmPFC patients, then, should have “compartmentalized minds,” where discordant ideas are rarely compared and falsiﬁed with one another. Indeed, vmPFC patients tend to be high in authoritarianism (Asp et al., 2012), a trait highlighted by a capacity to hold mutual agreement of contradictory ideas (Altemeyer, 1996). vmPFC patients are also prone to pathological confabulation, where they truly believe their (sometimes ﬂorid) assertions, even though contradictory evidence to these assertions is salient and obvious (Gilboa and Moscovitch, 2002). Our results also indicated that vmPFC patients had higher intention to purchase the misleadingly advertised products than BDC or normal comparisons. Undoubtedly, other, independent factors outside the study’s design likely have stronger inﬂuences during an actual purchase decision process (e.g., the usefulness of the product and available ﬁnancial means for an individual), than a single misleadingly advertised product aspect. These indepen- dent factors may have differentially affected the purchase intention data; e.g., the participants gave higher purchase intention ratings to the “deception-corrected” ads compared to the “deception- uncorrected” ads. Thus, because the experimental design used different (and unmatched) products across the types of ads, other issues such as usefulness and monetary concerns probably factored greater in the participants’ purchase intention. However, it is notable that vmPFC patients had the highest purchase intent of any group. VMPFC patients are notorious for their poor decision-making in ﬁnancial and social situations. They often claim that an inappropriate decision “feels right”; and there is substantial evidence suggesting that vmPFC patients lack affec- tive signals which normally steer individuals toward advantageous decisions (Damasio, 1994; Bechara et al., 1996, 2000). The FTT asserts that the cognitive process which selects the item eventually chosen from a decision-making process is governed by doubt (or false tags) which are affective in nature (Asp and Tranel, 2012). As an individual mentally represents each potential choice, the vmPFC acts to “doubt” or to negatively bias the inappropriate or undesirable representations away from a behavioral action. Appropriate or desirable response selection, then, is the result of the “ﬁttest” choice representation; i.e., the representation with the least negative biases (or false tags) attached to it. Here, we suggest the cognition to purchase a speciﬁc item is a belief and individuals must “false tag” this belief with other extant cognitive information. For instance, in regard to the “Legacy Luggage” we propose that normal individuals believe the initial cognition “I will purchase the Legacy Luggage” but then “falsify” that cognition with discordant extant cognitions, e.g., “I just bought new luggage” or “I don’t have time to go on any trips.” Other product aspects (including the mis- leading aspects) may play a role in the purchase decision, e.g., “It is made in the US” (strengthening the belief) or “The color of the luggage is unappealing” (increasing false tags) as well. Although we cannot specify what potential cognitions individuals may offer for falsiﬁcation, in this decision-making scenario, vmPFC patients should be more likely to intend to purchase advertised products. Our results provide some initial evidence for this view. We believe our results have implications that extend beyond unethical marketing campaigns, although they do directly impact marketing ethics in brain damaged individuals. This study adds to the growing evidence that belief and disbelief are not governed Frontiers in Neuroscience | Decision Neuroscience July 2012 | Volume 6 | Article 100 | 8