Abstract
Researchers who use undergraduate participants may be concerned about variation in data quality at different times of the semester. For instance, students who are more self-controlled may get their course credit earlier in the semester whereas those who procrastinate may wait until the end. Therefore, a potential time-of-semester effect may influence research data. This study sought to examine the relation between time of semester and delay discounting (DD)—a process that refers to an individual’s sensitivity to delayed rewards. DD may also directly relate to the decision to participate in research. Undergraduate participants completed money (n = 149) and food (n = 150) DD measures. Patterns in DD were examined across the semester. The number of systematic responders (i.e., those that follow a hyperbolic discounting curve) was also examined to determine the extent to which inattentive or random responding might be related to time of semester. Regression analyses revealed that money DD was consistent and stable across the semester. Food DD, controlling for subjective hunger as a co-variate increased slightly, though significantly, at the end of the semester. The percentage of participants with systematic discounting remained high throughout the semester for money and food DD, however, food DD had more variability, particularly towards the middle of the semester. Therefore, for college students, monetary DD is consistent across time of semester, but food DD slightly increases as the semester ends.