Using the "Search Image"

Petrified Wood, Alki Point

When I patrol the beaches near my home, looking for colorful or unusual rocks, I try to keep a mental image of what I am looking for, what scientists call a "search image." This refers to having a visual sense of what you're after when you set out, which can give you an advantage in spotting one specific kind of rock among thousands. Normally, I look for bold patterns, or bright colors - the easiest things to see. But today I made an effort to look at black rocks. My goal? To find specimens of petrified wood.

As I have mentioned in earlier posts, there is a form of black petrified wood that I have found many times on local beaches, though normally as small cobbles that reveal their patterns only after polished. I have no idea where the rock originates, but I am guessing it is somewhere relatively nearby, simply judging by the relative abundance of the stuff.

So I set out today with the idea of concentrating on finding these pieces of dark wood. This may be why I found this piece within 15 minutes of searching the beach, by far the largest piece of petrified wood I have ever found along the shore.  Did my "search image" make the difference, making this rather drab piece of rock stand out?  I think it did.

Though this piece looks drab now in its unpolished state, I will try and post a picture of it after polishing - look for it a few weeks from now. Until then, I will probably be back looking for other pieces of streaky black rock...