jQuery function to toggle Magento layered navigation attributes. Change .slice(1) to how many lists you want displayed by default.

Magento jQuery function for accordion style layered navigation

jQuery(document).ready(function(){
// Adds open and close option for sidebar filters
	jQuery('#narrow-by-list > dt:first').addClass('expanded');
	jQuery('dl#narrow-by-list > dd').slice(1).hide();
	jQuery('dl#narrow-by-list > dt a').click(function(){
		jQuery(this).parent().next().slideToggle('slow');
		jQuery(this).parent().toggleClass('expanded');
		return false;
	});
	
});

for me is not working. Magento 1.9.2.3 + Extension SEO layered navigation
It works with:

jQuery(document).ready(function(){
        // Adds open and close option for sidebar filters
            jQuery('dl#narrow-by-list > dt:first').addClass('expanded');
            jQuery('dl#narrow-by-list > dd').slice(1).hide();
            jQuery('dl#narrow-by-list > dt').click(function(){
                jQuery(this).next().slideToggle('slow');
                jQuery(this).toggleClass('expanded');
                return false;
            });
        });

`<script>

var $j= jQuery.noConflict();// no conflict method

$j (document).ready(function(){

$j("#narrow-by-list > dt").click(function(){

if(false == $j(this).next().is(':visible')) {

$j('#narrow-by-list dd').slideUp(300);

}
$j(this).next().slideToggle(300);

});

$j('#narrow-by-list dd').hide();

$j('#narrow-by-list dd:eq(0)').show();

});

</script>`