I'm a trained graphic designer, let me take a crack at explaining it:
Serifs make it easier to identify individual letters. When you are new to an alphabet (ESL, learning latin-based lettering, or a child) having the serifs makes it easier to identify letters.
Serifs are also better than sans-serifs for reading in low lighting situations, or the holy grail of legibility: when the page you're reading is moving as much as you are (e.g. reading a newspaper on a bus/subway, reading a book on a train, etc)
Sans-serifs USED to be recommended for digital displays because digital displays had a much much lower resolution than print (72-96 dots per inch, compared to print resolution of 300 dots per inch) so that meant that on old personal computers serifs looked chunky and heavy. They weren't thin and elegant, and because of this the sans-serif fonts just looked 'cleaner'.
Fast forward to 2014 when the screens most people have in their pockets have 324+ dots per inch and are actually a higher resolution than much printed material. Does the rule still apply? I'm not so sure anymore…
"Sans serif is better for children learning to read"
Books produced for children are often printed with sans serif text as teachers claim that the simplicity of the letter shapes makes them more recognisable ( Coghill, 1980) , Walker, 2001 ). But studies with child participants have found no difference in their ability to read either style of typeface. ( Coghill, 1980) ; Zachrisson, 1965 , Walker, 2001 )
Serifs make it easier to identify individual letters. When you are new to an alphabet (ESL, learning latin-based lettering, or a child) having the serifs makes it easier to identify letters.
Serifs are also better than sans-serifs for reading in low lighting situations, or the holy grail of legibility: when the page you're reading is moving as much as you are (e.g. reading a newspaper on a bus/subway, reading a book on a train, etc)
Sans-serifs USED to be recommended for digital displays because digital displays had a much much lower resolution than print (72-96 dots per inch, compared to print resolution of 300 dots per inch) so that meant that on old personal computers serifs looked chunky and heavy. They weren't thin and elegant, and because of this the sans-serif fonts just looked 'cleaner'.
Fast forward to 2014 when the screens most people have in their pockets have 324+ dots per inch and are actually a higher resolution than much printed material. Does the rule still apply? I'm not so sure anymore…