|Alderfer's ERG theory differs from Maslow's Need Hierarchy insofar as ERG theory demonstrates that more than one need may be operative at the
same time. ERG theory does not assume a rigid hierarchy where a lower need must be substantially satisfied before
one can move on.
Alderfer also deals with frustration-regression. That is, if
a higher-order need is frustrated, an individual then seeks to increase the satisfaction of a lower-order need.
This is consistent with Douglas MacGregor's observations in explaining his Theory X/Theory Y dichotomy: the inability to satisfy a need for
social interaction might increase the desire for more money or better working conditions. ERG theory also accounts for
differences in need preferences between cultures better than Maslow's Need Hierarchy.