Why is $and not 1?

wtfphparray_reduce.php

<?php

if( !function_exists('es_preit') ) {
	function es_preit( $obj, $echo = true ) {
		if( $echo ) {
			echo '<pre>';
			print_r( $obj );
			echo '</pre>';
		} else {
			return '<pre>' . print_r( $obj, true ) . '</pre>';
		}
	}
}

$conds = array(1,1);

function reduce_and($a, $b) {
	$a *= $b;
	return $a;
}

$and = array_reduce($conds, 'reduce_and');
es_preit(array(
	'this is $conds' => $conds,
	'this is $and' => array(
		$and, gettype($and)
	)
));

/*
Prints: 
Array
(
    [this is $conds] => Array
        (
            [0] => 1
            [1] => 1
        )

    [this is $and] => Array
        (
            [0] => 0
            [1] => integer
        )

)
*/

The first time reduce_and is called, $a === NULL after looking at it with gettype. I'm lost as to why.

SOLVED.

For anyone wondering, array_reduce needs to work on arrays that have only one element, and it'd be grand if in those cases PHP wouldn't die. Thus the initial value is important. If not set, it's null, and null * 1 = null.