if ('constant' == $variable) vs. if ($variable == 'constant')

Question

Lately, I've been working a lot in PHP and specifically within the WordPress framework. I'm noticing a lot of code in the form of:

if ( 1 == $options['postlink'] )

Where I would have expected to see:

if ( $options['postlink'] == 1 )

Is this a convention found in certain languages / frameworks? Is there any reason the former approach is preferable to the latter (from a processing perspective, or a parsing perspective or even a human perspective?)

Or is it merely a matter of taste? I have always thought it better when performing a test, that the variable item being tested against some constant is on the left. It seems to map better to the way we would ask the question in natural language: "if the cake is chocolate" rather than "if chocolate is the cake".