Idiot

The village of Wichad was home to a particularly celebrated idiot. He was well known throughout the region for always having the wrong idea about money. You see, whenever he was offered the choice between two coins, he would inevitably take the lower one and then go off, utterly delighted with his choice. One townsman in particular had trouble understanding why the fool behaved the way he did. He tried an entire range of combinations on that man, trying different coins of different sizes, ages and even shininess. Even Though the fool seemed to have no knowledge of the value he would always choose the option that would leave him worse off. In the end the townsman was able to rule out the coins weight, thickness, diameter, colour, cluster and even age as the factor that made the idiot invariably decent on the offering of lesser value. It certainly was not bad luck.

How come the fool always took the less valuable coin?