In very simplistic terms, the concept is that we have a range of - valid - needs, and that it is necessary to satisfy the more basic needs before being able to address the needs further up the hierarchy.That is a very useful device in the overwhelming majority of circumstances, but I argue that it is not universal: there are some circumstances where "higher" needs are addressed first. As an example of that, consider a - literally (i.e., someone in a famine situation) - starving parent who feeds their child before themself.
A couple of decades ago, while working on a book on rescue which I never finished, I did a few - light-hearted - sketches to help illustrate what I was writing about. The following sketch was meant to help illustrate the classic, hierarchical arrangement of needs - and I was using animals in an anthropomorphic way as a cartoon device (incidentally, I had intended to redraw these to be a bit more distinct, but as I haven't had time to do so over the last few decades, I've decided to post them now, as they are with a hope they may be of some use or lead to someone doing something better):
(the self esteem sketch is meant to be a before and after sketch)
PS - Having written all that some time ago, I have just come across an interesting alternative approach to needs: see https://medium.com/@dinamin84/why-i-want-to-tear-down-maslows-pyramid-42a2a0e063bf. See also:
- https://psyche.co/ideas/our-age-of-crises-needs-bollnows-philosophy-of-hope
- https://politicalmusingsofkayleen.blogspot.com/2019/10/a-hierarchy-of-needs-for-nations.html