&gt; I think a 5 year old with no preconceived notions of a user interface is probably the best validation of whether a device is &quot;usable.&quot;<p>But Western 5-year-olds have already had 5 years to watch their parents use contemporary technology.  I&#x27;m not sure there&#x27;s such thing as a &quot;blank slate&quot; here.  And I doubt the average 5-year-old from a rural town in a third-world country is going to pick up an iPhone as easily as an American one.  You&#x27;re picking like 1% of the world population and making them the benchmark for universal design.  I suppose the ultimate end to this line of reasoning is that there is no such thing as perfectly universal design, and I&#x27;m OK with that.<p>&gt; I have actually never even heard of a single person picking up and iPhone and saying &quot;I can&#x27;t figure this out - it&#x27;s unusable!&quot; until your post.<p>When did I say that?  You might have me confused with the GP poster.<p>&gt; Perhaps you feel Apple should have designed a beautiful rotary phone?<p>Why not?  Many 5-year-olds probably could use rotary phones just fine back in the day.  Maybe Apple doesn&#x27;t actually have a monopoly on making it possible for 5-year-olds to use technology.