To examine the effect of extensive life science applications on student attitudes to learning physics, we analyzed CLASS data from life science students in introductory physics. We compare the same students' responses from the first semester, taught with a standard syllabus, to the second semester, taught with extensive life science applications (IPLS). Although first semester responses become less favorable (pre to post), IPLS responses show an increase in favorable and a decrease in unfavorable responses. This is noteworthy because improvement is rarely observed without direct attention to attitudes/beliefs, and suggests IPLS courses are one possible approach to improving attitudes. Finally, we analyzed CLASS responses by gender, major, students' stated goals in taking physics, and initial interest in physics; initial interest was determined from CLASS items chosen based on the Four-Phase Model of Interest Development. Most notably, we find that in the IPLS course, students identified as having low interest initially had the greatest gains.