Asp et al. Number Age (SD)* Education (SD) Sex** Lesion size (SD)† Table 1 | Demographic and neuroanatomical data. vmPFC 18 60.4 (10.6) 13.8 (2.7) 12 M; 6 F 51.7(40.3) BDC 21 50.2 (11.0) 14.3 (2.3) 6 M; 15 F 21.9 (15.3) WAIS-III, Wechsler Adult Intelligence Scale-III scores (FSIQ, full-scale IQ). WRAT, Wide Range AchievementTest scores (Read, Reading Standard Score). AVLT, Audi- tory Verbal Learning Test scores (an index of memory function at 30 min). CFT, Complex Figure Test recall scores (an index of memory function at 30 min). TMT, Trail Making Test Part B scores, an index of divided attention and multi-tasking. WCST,Wisconsin Card SortingTest Perseverative Errors, an index of reasoning and concept formation (executive functioning). There were no signiﬁcant differences between the groups for any of the neuropsychological tests. substance abuse, and dementia. Participants gave informed con- sent approved by the Institutional Review Board of the University of Iowa. STIMULI AND PROCEDURE Participants were given a booklet that consisted of eight adver- tisements that one might encounter in a magazine or newspaper. Each ad was based on real-world misleading advertisements as deemed by the rulings of the FTC, as shown in FTC Decisions (Federal Trade Commission, 1991) and Complying with the Made in USA Standard (Federal Trade Commission Bureau of Con- sumer Protection, 1998). These advertisements were misleading for a number of reasons, ranging from the withholding of crucial information about the product to the use of biased graphs. For example, in an advertisement for “Legacy Luggage,” the original misleading version had the headline “Legacy brings you the ﬁnest American Quality luggage.” The FTC stated that any advertise- ment that has “American Quality” on it conveys that the item in question was made in the U.S.A. In fact, the luggage was actu- ally not made in the U.S.A., but instead was manufactured in Normal 10 60.7 (8.9) 15.8 (3.0) 7 M; 3 F BDC 104.7 (11.5) 96.6 (8.2) 9.2 (2.9) 17.2 (5.4) 77.8 (43.2) 12.6 (8.1) Neural correlates of credulity Mexico, and then inspected in Tennessee, and thus was mislead- ing. Three ads were classiﬁed as “deception-uncorrected” and were left unchanged from the FTC-ruled “misleading advertisement” classiﬁcation. However, “deception-uncorrected” ads assume that all individuals have a similar knowledge base regarding potential objections to the misleading portions of the ads. This assumption leaves open the possibility that some individuals may not have, or cannot access, cognitions that should induce doubting. To address this issue, we developed “deception-corrected” ads which provide explicit information that should induce doubting, by modifying three misleading ads with a disclaimer at the end of the ad. The dis- claimers in the “deception-corrected” ads speciﬁcally rebutted the misleading aspect of the ad. For example, in an advertisement for “NatureCure,” the misleading ad describes a natural pain reliever that provides relief from headaches “without the side effects of over-the-counter pain relievers.” The end disclaimer refutes this claim by noting, “This product can cause nausea in some con- sumers when taken regularly.” Thus, for the “deception-corrected” ads, all participants were given the same speciﬁc knowledge to doubt the misleadingly advertised claim. Finally, there were two “ﬁller” advertisements, one placed at the beginning and the other at the end of the booklet. These were used to help buffer against primacy and recency effects, and were not scored. This left six critical advertisements: three “deception-uncorrected” and three “deception-corrected.” Each ad highlighted a distinct product: the “deception-uncorrected” stimuli advertised a doll, luggage, and a vitamin supplement drink; the “deception-corrected” stimuli advertised a car, a pain reliever, and mutual funds. Participants read over the advertisements at their own pace and when ﬁnished, they were given a paper questionnaire which assessed participant reactions to each advertisement and product. Participants could not refer back to the advertisements during the questionnaire; instead, they needed to recall their impressions of each product from memory. Readers who are interested in knowing more about the advertising stimuli and their development may contact the senior author via email. Two critical dimensions were assessed for each advertisement: (1) credulity toward the misleading aspect of the advertisement, and (2) purchase intention, i.e., how likely was the participant to buy each item should it become available in their area. The credulity measure asked “What do you believe to be true about this product?” and was assessed on a Likert scale, anchored at each end by a belief about the product being advertised. The Likert scales on the questionnaire contained no numerals but had 7 empty spaces (of equal size) between the two anchors. Participants marked the empty space they considered appropriate. Numbers for the Likert scale were added post hoc, and ranged from 1 to 7, with lower values reﬂecting increased belief in the misleading aspects of the ads and higher values reﬂecting increased skepticism for the misleading aspects of the ads. For example, the previously mentioned Legacy Luggage advertisement dealt with whether or not the luggage was made in the U.S.A. The credulity question concerning that adver- tisement was anchored at space 1 by “The Legacy Luggage Set is made in the United States” and at space 7 by “The Legacy Luggage Set is NOT made in the United States.” The purchase intention measure was assessed by asking, “What is the probability that you would buy the product when it becomes available in the area?” Age and education are presented in years; lesion size is presented in cubic cen- timeters. *BDC patients were signiﬁcantly younger than vmPFC patients and normal par- ticipants. **The BDC group had a signiﬁcantly lower proportion of males relative to females than the vmPFC and normal groups. †VMPFC lesions were signiﬁcantly larger than BDC lesions. Table 2 | Neuropsychological data for the lesion groups. WAIS III – FSIQ (SD) WRAT – Read (SD) AVLT – 30 min recall (SD) CFT – 30 min recall (SD) TMT – Part B (SD) WCST – Pers. Errors (SD) vmPFC 108.5 (16.8) 99.4 (9.8) 8.5 (3.6) 20.0 (7.5) 76.7 (34.9) 22.1 (24.7) www.frontiersin.org July 2012 | Volume 6 | Article 100 | 5