Calorie estimates from Study 1.

<p>Participants were asked to estimate to the calorie content of two mains presented alone, or the same two mains presented with a green healthy side, or the same two mains presented with a red healthy side. Histograms show the distribution of the calorie estimates for all three conditions combined. Since calorie estimates follow a positively skewed distribution, the natural log is taken, and the data re-plotted. Error bars indicate SEM.</p

Mean number of draws to decision. Error bars are 95% confidence intervals.

<p>Mean number of draws to decision. Error bars are 95% confidence intervals.</p

Competing hypotheses of how calories estimates are made.

<p>Left: Chernev proposes that individuals assess the vice or virtue nature of foods, and use this to estimate the healthiness of the combination of foods, which is then used to determine a calorie estimate <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071475#pone.0071475-Chernev2" target="_blank">[2]</a>. Right: An anchoring and adjustment account <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071475#pone.0071475-Tversky1" target="_blank">[9]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071475#pone.0071475-Tversky2" target="_blank">[10]</a> proposes that individuals use the calories in the reference food as an anchor, adjusting this to capture the difference between the reference food and the target food.</p

Calorie estimates and healthiness scores from Study 3.

<p>Participants were asked to estimate the calorie content of a main dish presented alone, or with a small portion of a healthy side. In addition, before making their calories estimate, participants were shown a reference food labeled as 500 calories. This was either a main dish alone or a main dish with a healthy side. They were then asked to estimate the healthiness on a 5 point scale for the same two food images. Error bars indicate SEM.</p

a,b. Draws to decisions of the individual participants in two experimental conditions during their 3 visits.

<p>a,b. Draws to decisions of the individual participants in two experimental conditions during their 3 visits.</p

a,b. Mean confidence estimates for the two sequences in which participants were asked to rate the confidence of their decision.

<p>The red line represents the methamphetamine condition; blue represents the placebo condition, and green represents the combined amisulpride and methamphetamine condition.</p

Mean number of draws to decision.

<p>Mean number of draws to decision.</p

Competing predictions of the conditions under which a negative calorie illusion (NCI) will occur.

<p>The letters A, B, x and y represent food. Main meals vice items, such as a cheeseburger, are represented by capital letters A and B. Healthy side dishes, such as celery sticks, are represented by lower-case letters x and y.</p

Relating Cue Responses to Aberrant PE During Blocking.

<p>The degree to which subjects inappropriately engage DLPFC during blocking trials correlated positively with their tendency to stronger GSR responses to ketamine-reactivated cues. This result is internally consistent with the Stage 3 finding – excessive responses during blocking and attenuated responses during its violation portend further memory strengthening in the context of ketamine. Plot features the difference in GSR response to the cue reactivated under ketamine from the cue reactivated under placebo on x-axis, rDLPFC responses during blocking trials (compared with control trials) on the y-axis.</p

Blocking Behavior and its Relation to Brain Responses.

<p><i>A. Behavioral Predictions For Blocked and Control Cues.</i> Subjects predicted with low confidence about the blocked cue, when exposed to it at Stage 3; confirming that blocking had taken place. Error bars represent SEM. Y-axis represents subjects' predictive strength; their degree of confidence (duration of predictive button push response) multiplied by correctness of their prediction. Hence lower scores reflect uncertain and unstable predictions, which we observed to blocked cues when compared with blocking control cues (whose causal association with the allergy is more robust). <i>B. Relating Predictions about the Blocked Cue (Stage 3) to Blocking Responses.</i> Subjects who showed the lowest confidence when predicting what would happen following the blocked cue had the most attenuated right DLPFC response during blocking trials. X-axis represents the right DLPFC parameter estimates extracted from a contrast image comparing blocking trials with blocking control trials. Y-axis represents subjects' behavioral predictions about the blocked cues prior to seeing their predictive outcomes at the first trials of Stage 3. <i>C. Relating Brain Responses During Blocking to those during Violation.</i> Subjects with the most attenuated DLPFC response during blocking showed the greatest right DLPFC response when that blocking contingency was subsequently violated. X-axis represents the right DLPFC response to observing the blocked cue causing the allergic response during Violation (Stage 3), compared with control event. Y-axis represents right DLPFC response to blocking trials compared with blocking-control trials.</p