The main reasons for problems in opening packages are the
large forces required, tear tabs that are too small, and the poor
visibility of the opening mechanisms (Dittrich and Spanner-Ulmer,
2010; Marks et al., 2012). In our study, too, the factors listed above
(force required, too small a tear tab) and, in addition, the poor
palpability of the tear tab (i.e. poor separation of the upper and
lower tab), reflect the difficulties experienced in the opening process
and the decisive differences between the two packages tested.