Guidelines for interviewers frequently include instructions to read question texts exactly as they are worded. Deviations from these guidelines on standardized interviewing might affect the comparability of survey answers and impair the quality of data. This paper contributes to the literature on interviewer behavior by analyzing how interviewers change their reading behavior during fieldwork and whether this behavioral change influences the response behavior of survey respondents. We use item-level paradata from the Survey of Health, Ageing and Retirement in Europe (SHARE) to measure interviewers' reading times and focus our analyses on introductory questions that do not require an immediate response by the respondent. In contrast to prior research, this focus enables us to disentangle the reading times of interviewers from the response times of respondents. Based on fixed effects regression, our results show systematic changes in interviewers' reading times of introductory items: First, reading times significantly decrease over the survey's field period, even after controlling for relevant respondent characteristics and specific aspects of the interview situation. Second, a cross-national comparison, including fourteen European countries plus Israel, reveals that the decrease is uniform in almost all countries, suggesting its generalizability across different cultural contexts. Third, the decrease in reading times influences response behavior to varying degrees. Response behavior is affected if introductions contain relevant information for understanding or fulfilling the required task and especially if the response refers to within-survey requests. On the basis of these findings, we discuss the possible consequences for questionnaire design, interviewer training, and fieldwork monitoring.