131 Attentive Vision

Attention can be deployed several ways and is required for conjunction search tasks.

Not everything just jumps out at you.

• Basic features, like color, orientation, direction of motion serve as natural segmentation cues.
• More complex tasks, such as “find the T in with the L’s”, require attention.
• The parietal cortex appears to be necessary for this.

Loads of psychophysical and electrophysiological experiments demonstrate three strategies:

1. Feature-based attention: you can look for a particular feature anywhere.
   – Ex. Look for something that is black, metal, and has a diamond design.
2. Spatial attention: you can look in a particular place for anything.
   – Ex. Look at the top right of the photo.
3. Object-based attention: you can deploy attention along an object, even if it’s partially occluded.
   – Ex. Look at the street lamps on the bridge in the photo.