Is The magical number 7 still valid? George A. Miller published "The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information" in 1956 and is one of the most highly cited papers in psychology.  It supposedly argues that the number of objects an average human can hold in working memory is 7 ± 2. This is frequently referred to as Miller's Law.[1]

I've learned this in school as well, and I often use the magic number seven when it comes to grouping of elements in more logical units. However recent research question Miller's Law stating that the correct number a human being can hold in working memory is three or four[2]. In my daily life, I can see that this is more likely. When I go shopping, I need to write a shopping list if there are more than four things I need to buy and by this not forget what it was I'm supposed to buy. One could argue that my working memory is worse than average, but I would never agree to such a statement. 

But the question remains and is puzzling my mind... 
Is The magical number 7 still valid? 



[1] Wikipedia article on Miller's Law

[2] Jeanne Farrington EdD, "Seven plus or minus two"
As far as I recall, the &quot;magic&quot; of the number seven is that George Miller had to give a 1h-presentation while not having enough research on one particular topic to talk about this long. So he tried to connect unrelated lines of research, with the only connection between them being that they show cognitive limitations of similar magnitude (&quot;7+/-2 items&quot;). However, the comparison was not very serious and mostly rhetorical.
So I guess the short answer is: No it is not valid, and it has never really been.
Here is an short article that answers your question in more detail:

Cowan, N., Morey, C.C., &amp; Chen, Z. (2007). The legend of the magical number seven. In S. Della Sala (Ed.), Tall tales about the mind &amp; brain: Separating fact from fiction (pp. 45-59). Oxford, U.K.: Oxford University Press.

And here is Millers original article, it's actually fun to read:

Miller, G. A. (1956). &quot;The magical number seven, plus or minus two: Some limits on our capacity for processing information&quot;. Psychological Review 63 (2): 81–97.