IMC (Instructional Manipulation Check) and DQS (Directed Question Scales) are trap questions designed to identify careless and insufficient effort responding. These measures are widely implemented by researchers and practitioners in contemporary survey methodologies. Additionally, these trap questions may exert a spillover effect, encouraging respondents exposed to them early in a survey to approach subsequent questions with increased attentiveness. Although this effect has been observed in prior studies, consistent empirical evidence remains scarce. This study re-examines the phenomenon using a novel response accuracy evaluation method that contrasts survey responses with actual behavior, employing a single-source dataset integrating behavioral log data and survey responses. We conducted survey field experiments to collect four conditions data in a 2×2 design by placing IMC or DQS at the beginning or the end of the survey and evaluated the survey response accuracy. The findings reveal that IMC functions to enhance respondent attentiveness, whereas DQS exhibits no comparable effect. These results offer practical insights for improving survey quality.

Many consumers, especially restrained eaters, believe that individually packaged food helps them control how much they eat. However, some studies have found that when the same total amount of food is offered either in multiple small packages or in one large package, restrained eaters sometimes eat less from the large package. This study explored why this happens. In a lab experiment, participants received the same amount of food in either a bulk or segmented format. We measured how the packaging format influenced how much they thought “consumption limit” and how much they ate. We also compared restrained and unrestrained eaters.

The results showed that restrained eaters set smaller consumption limits and ate less when the food was in one large package. This pattern was not observed among unrestrained eaters. These findings suggest that bulk packaging may make restrained eaters more cautious about overeating, leading them to apply stricter self-control. This study helps explain how packaging format influences eating behavior and offers useful insights for food marketing and health promotion.