Thursday, May 17, 2007

High Arousal Evidence for DELCAM Model

One of my passions is studying attention. Most often I talk about paying attention to mediated messages, but the general principles also apply to non-mediated environments.

I have attempted to model real-time human attention and emotion in an artificial neural network, which I have called dynamic, embodied limited capacity attention and memory, or DELCAM. You can read about DELCAM in the current issue of the journal Media Psychology (also read more about DELCAM in this blog posting).

DELCAM was born in 2003 when I tried to formally model Annie Lang's limited capacity model of mediated message processing. Although Lang's model has been instrumental in my thinking, it was difficult to formally implement.

This failed implementation set me back, and I had to spend some quality time with the brain. I had seen enough evidence to believe that attention was limited-capacity, but I needed to spend some quality time with the brain attempting to figure out the nature of this limitation.

Eventually I settled upon the idea of physiological arousal forcing the brain to focus more closely on the central object at hand and less on the periphery. It's a simple idea, really, and it incorporates both common sense and the thinking of several of leading scholars.

Importantly, however, DELCAM correctly predicts that recall increases in arousing contexts, whereas recognition will suffer (again, you can read more about this here).

Because I study mediated messages; however, I do not work at the extreme ends of arousal. Although you get pretty scared watching a horror movie, it does not compare to the horror of having a villain with a knife actually chase you.

In those cases of extreme arousal -- when literally your life is on the line -- what happens to attention. Does it fit with the conceptualization of DELCAM?

I found a partial answer while reading Malcom Gladwell's book, Blink.

Although television shows police officers drawing their guns all of the time, the vast majority of police officers navigate an entire career without ever firing a gun ... ever. So when presented with the necessity to use deadly force, the police officer is in the rarest of circumstances. And afraid for her or his life.

The sympathetic nervous system surges, and the heart pounds as if it will tear through the chest.

Here's Gladwell quoting a police officer in David Klinger's book, Into the Kill Zone.

When he started toward us, it was almost like it was in slow motion and everything went into a tight focus ... When he made his move, my whole body just tensed up. I don't remember having any feeling from my chest down. Everything was focused forward to watch and react to my target. Talk about an adrenaline rush! Everything tightened up, and all my senses were directed forward at the man running at us with a gun. My vision was focused on his torso and the gun. I couldn't tell you what his left hand was doing. I have no idea. I was watching the gun. The gun was coming down in front of his chest area, and that's when I did my first shots.

I didn't hear a thing, not one thing. Alan had fired one round when I shot my first pair, but I didn't hear hm shoot. He shot two more rounds when I fired the second time, but I didn't hear any of those rounds, either. We stopped shooting when he hit the floor and slid into me. Then I was on my feet standing over the guy. I don't even remember pushing myself up. All I know is the next thing I knew I was standing on two feet looking down at the guy. I don't know how I got there, whether I pushed up with my hands, or whether I pulled my knees up underneath. I don't know, but once I was up, I was hearing things again because I could hear brass still clinking on the tile floor. Time had also returned to normal by then, because it had slowed down during the shooting. That started as soon as he started toward us. Even though I knew he was running at us, it looked like he was moving in slow motion. Damnedest thing I ever saw (Blink, pp. 223-224).

DELCAM suggests that limited-capacity cognition allocates attention toward the "target" as physiological arousal increases (an ironic choice in terminology, as it turns out). This police officer's recount suggests that this reallocation can continue along a continuum until superfluous channels -- in this case audio -- are altogether removed from conscious processing.

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