How to prevent insults from unconsciously causing negative emotions? When someone is insulted, they can feel anxiety and shame, even though his/her conscious mind knows the insult isn't true and tries to be as logical and unemotional about it as possible.

Positive self-talk ("I am relaxed", "The insult is false" or similar) isn't always effective for those experiencing this. 

It may be natural to feel that way (social self-preservation), but it seems to me that there should be effective methods to control the unconscious mind in these situations. 

How can an individual prevent insults from unconsciously causing negative emotions?
Mindfulness meditation can help reduce the intensity of emotional pain. This study explores this further. Even listening to music may help reduce the intensity of pain.

Source

Christopher A. Brown, Anthony K.P. Jones. Meditation experience predicts less negative appraisal of pain: Electrophysiological evidence for the involvement of anticipatory neural responses. Pain, 2010.  doi:10.1016/j.pain.2010.04.017

David H. Bradshaw, Gary W. Donaldson, Robert C. Jacobson, Yoshio Nakamura, C. Richard Chapman. Individual Differences in the Effects of Music Engagement on Responses to Painful Stimulation. The Journal of Pain, 2011; 12 (12): 1262. doi:10.1016/j.jpain.2011.08.010