There is a famous thought experiment proposed by Schrodinger which investigates the effect observation has on a system. He proposed that a system, in this case the cat in a box, can exist in two states simultaneously as long as it is not observed. The cat can be both alive and dead at the same time, but if the box is opened and the cat observed the quantum superposition of the two states collapses and the cat is observed as either alive or dead.
Two recently published experiments shed light (!) on this and confirm that quantum effects at very small scales can influence macroscopic objects ( perhaps a kitten rather than a cat).
The ability to bridge the gap between the very small scales where quantum effects determine events and the scales we are used to dealing with in everyday life has major implications, for example computing, materials science, artificial intelligence and developing an understanding of biological systems.