THE ROUGH GUIDE TO PSYCHOLOGYAnatomy of a psychology experiment
An important experiment by Harvard University psychologist Ellen
Langer and her colleague Judith Rodin conducted in the 1970s found
that elderly nursing home residents given more responsibilities and
choices went on to live longer and enjoyed better health. This study
provides a useful way of exploring the basic anatomy of a typical
psychology experiment. The residents who were given the chance to
care for a houseplant, to choose where to receive visitors, and which
films to watch were the experimental group. The residents who didn’t
receive these benefits (they were given a houseplant but told the staff
would care for it) became the control group, with which the experi-
mental group could be compared.
The residents who took part in the study were known as partici-
pants, referred to collectively as the study sample. Ideally, the residents
should have been selected at random (to avoid experimenter bias) and
if the findings were to generalize to all nursing home residents (the
population of interest), they should have been representative of that
broader group.
Psychology experiments usually involve measuring something and
in this case both groups of residents completed tests of their health,