The official Yale copyright policy:
https://ventures.yale.edu/yale-university-copyright-policy
Here is an excerpt:
The University will own the copyright to works created (i) by staff members or postdoctoral fellows or postdoctoral associates in the course of their assigned duties of employment, (ii) by student employees in the course of their assigned duties of employment, including duties as teaching or research assistance, or (iii) by faculty members as part of an assigned task where the assignment explicitly states that the work will be owned by the University.