Why do some people seem to disregard the choice of doing nothing (The Zero Choice)? In many areas of life we have a choice between multiple options: if we are hungry and we want to go out to eat, we have a number of places to choose from (McDonalds, etc).  However, we also still have the 'Zero Choice' (my terminology) of not eating out at all and getting food some other way.

In my personal life, I've noticed (perhaps falsly) that a fair number of people, once they've made a general choice (in the example: eating out), they disregard the 'Zero Choice' (not eating out) and become fixated on the sub-choices (where to eat out).

Is there a noticable difference in mental activity between people who don't consider the 'Zero Choice' and people who do?



Original Question: 


  In my life I've noticed that people rarely see the 'nothing' choice. 
  Rather than choosing this or that, there is also the choice of
  neither and both.  People I've interacted with often weigh their
  both, this, and that options fairly well, but many completely
  miss the neither/nothing option.
  
  More specifically, I've seen this in a couple girlfriends I've had and
  a couple guy friends also.  When trying to decide what to do, they'll
  settle on a type of activity (active/passive -> general category ->
  couple options) and then choose between a couple options.  However,
  rarely in these options do they include the idea of something
  completely different.  Meanwhile, this is something I do without
  thinking; other options are always present to me, and I have no
  difficulty in seeing, weighing, or choosing the neither option.
  
  These are poor examples and for that I apologize; but is this a
  recognized phenomenon? What neural differences are there between
  people who process the nothing option and people who don't?
  
  Has this even been researched at all?  Cursory Googling (the most
  available to me right now) has revealed nothing; I could be searching
  for the wrong thing though...
More generally, you are asking about a common tendency to substitute a sub-set of  alternative actions for the entire set without realizing it.

Beyond the contribution of pure habit, it seems to be related to several common decision making biases, including attentional bias and focusing effect, though it doesn't exactly match any.  I don't recall seeing this investigated directly.

"Zero choice" is a poor choice of terminology, it evokes the "null hypothesis" (as Ben Brocka alluded to in the comments), which in decision making usually means "do nothing", not a call to consider a broader set of alternatives.