Second, the median amount of motion and movement is reported, as determined by
Cutting et al (2011b).Motion is the optical change created bymoving objects, people, and
shadows; movement is that change created by camera motion or gradual lens change (a
zoom; see Gibson 1954).We calculated their combination by correlating next-adjacent frames
along the length of each ﬁlm—frames 1&3,2&4,3&5, . . . ,40377&40379, . . . , and so forth.