How do respondents construe ambiguous response formats of affect items?

Ambiguous response formats predict correlations from -.467 to -1 between opposite items, depending on whether the respondent's interpretation of the format is unipolar or bipolar. The authors present a procedure to investigate the proper interpretation in each case. It consists of applying nonparametric and parametric item response theory models (the Mokken and the graded response models) to pairs of opposite items in order to find the locations of the response options along the latent scale and, therefore, identify the response format construction. The authors tested this procedure on 4 samples (Ns=142-1,150) and 2 item pairs ("relaxed"-"tense" and "optimistic"-"pessimistic"). The results revealed that respondents constructed the formats as bipolar and supported the bipolarity of the item pairs.