  The two-particle differential transverse momentum correlator $G_{2}$ recently
measured in Pb$-$Pb collisions, emerged as a powerful tool to gain insight into
particle production mechanisms and to infer transport properties such as the
ratio of shear viscosity to entropy density of the medium created in Pb$-$Pb
collisions. In this poster, recent ALICE measurements of this correlator in pp
collisions at $\sqrt{s}=7$ and p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$
TeV are presented to search, in particular, for viscous effects expected to
arise in fluid-like systems produced in these collisions. The strength and
shape of the correlator are studied as a function of produced particle
multiplicity to look for longitudinal broadening that might reveal the presence
of viscous effects in these smaller systems. The measured correlators and their
evolution from pp and p$-$Pb to Pb$-$Pb are additionally compared to
predictions from Monte Carlo models, and the potential presence of viscous
effects is discussed.
