In the study below, performed by psychologists at Tufts University, the brain’s “Event Related Potential Response” (ERP) was observed after varying patterns of statements the listener can easily determine are true or untrue.  Specifically, they found that negation does not appear to interfere with cognition or assessment when the material is presented in a straightforward sentence structure.

We interpret this to refute common assertion that negative terms interfere with cognition or are less effective in affirmations or self talk.  Clear, coherent, sentence structure, whether or not positive or negating terms are present, is sufficient to induce the brain’s apparent decision response.

Association for Psychological Science (2009, February 13). True Or False? How Our Brain Processes Negative Statements. ScienceDaily.­ /releases/2009/02/090211122147.htm