Objective: To examine anchoring and adjustment processes in patients with ventromedial prefrontal cortex (vmPFC) lesions. When provided a question such as, “The top speed of the fastest man in the world is greater than 11 miles per hour.  What is the speed of this man?” people tend to heavily rely on the first piece of information provided (i.e., 11 mph)—this is referred to as anchoring.  Adjustment is the ability to adjust one’s answer away from this initial piece of information. Damage to the vmPFC produces impairments in judgment and poor and erratic estimations. Using the False Tagging Theory (FTT), we hypothesized that vmPFC patients’ responses to cognitive estimation-type questions (no anchor condition) will be more variable; and for high and low anchor estimation questions, prefrontal patients will show an increased anchoring effect. Method: Participants with vmPFC damage, brain-damaged comparison (BDC) and healthy adults (HA) participated in a neuropsychological test, the Knowledge Estimation Task (KET). The test consists of 15 trials per each of the 3 conditions: no anchor, high anchor with directional guide and low anchor with directional guide. Results: Preliminarily, vmPFC patients had more variability in their responses in the no anchor condition than HAs and BDCs. Moreover, the vmPFCs and BDCs showed an increased anchoring effect for high and low anchors than HAs. Conclusion: These preliminary results are consistent with our hypotheses, and suggest that the vmPFC might be crucial for normally adjusting from anchors during estimations. These findings extend understanding of neural mechanisms for complex judgment and decision making, and add to the intriguing roster of cognitive operations associated with vmPFC.