Likert Scale 3 2 1 0 1 2 3 possible? In my questionnaire I want to ask people to score on a dimensional Likert-type scale their attitude toward a specific target group. 
E.g. 
People with .... are 
stupid.... intelligent. 
I want to use the Likert rating 
3 2 1 0 1 2 3
The reason for this is that I do not want to prime people in a certain direction. As well, zero is for me a neutral score. However, do you have an example where this type of Likert rating has been used before? 
 A: Anything is possible but it would seem to create all sorts of interpretation difficulties.
In any case, while “Likert scale” has taken a rather broad meaning nowadays, this has little to do with what Rensis Likert did or the most common uses of similar scales and questionnaires.
Incidentally, Likert himself did not present any numbers to his participants, instead using letter indexes like “(a)”, “(b)”, etc. or, most famously, labels like “Strongly approve” and writing that (emphasis mine)

These numbers [i.e. the values assigned during scoring] were, of course, not present upon the SURVEY OF OPINIONS when taken by the subject.

If anything, what you are considering seems closer to something called the “semantic differential”. Looking that up might provide you with more relevant material to explore the statistical issues involved.
A: This form of likert-type scale is not possible. A likert scale should show subjective rating of an attribute on an ordinal scale. If 0 means neutral, then the values to the left of 0should show a rating lower than zero. In your case you may assign negative values to ratings below 0. And ratings above 0 should be greater than zero. However, which values should show higher or lower magnitude of rating depends on how you want to rate the attribute. In any case, the ratings should be distinct. You cannot use a value to apply to two different ratings. So, in your case what is the difference between a rating of 3 to the left of 0 and a rating of 3 to the right of zero? Two people on two different ends of the spectrum are going to be given the same value which is not logical.
