Examining the Link between the ‘Middle Means Typical’ Heuristic and Answer Behavior

Question interpretation in web surveys may not only depend on the textual content but also on visual design aspects. Research has shown that respondents seem to make use of interpretative heuristics when answering questions potentially influencing their answer behavior. In this study, we investigate the implications of the ‘middle means typical’ (MMT) heuristic, which suggests that respondents perceive the middle option of a scale as the most typical one. For this purpose, we use data from a survey experiment embedded in the probability-based German Internet Panel (N = 4,679) varying the inclusion of a non-substantive “Don’t know” option (with or without separation from the substantive options) and scale polarity (unipolar or bipolar). The four questions under investigation were adopted from the Big5 inventory dealing with agreeableness and openness. The results suggest that the MMT heuristic has a minor impact on answer behavior, as the separation of non-substantive options did not affect answer distributions and response times (as a measure of response effort). However, scale polarity influenced answer behavior and response times. Similar to what has been observed in previous studies, unipolar scales elicited more middle answers and bipolar scales elicited more positive answers. Bipolar scales also resulted in longer response times. Although design violations against the MMT heuristic do not seem to impact answer behavior, we still recommend exercising caution when designing scales with non-substantive options. We also highlight the necessity of testing scales differing with respect to polarity.