Visual coding and the deployment of attention
Attention can be set to select different aspects of the environment ranging from the global registration of scene properties to the focused analysis of the local conjunctions of features that distinguish individual objects. In the global processing mode, we suggest that people can access the gist of a scene, using the global layout and a parallel registration of some local features. They can also form a representation of the statistical properties of sets of similar objects. Studies of size judgments include tests for implicit priming of the mean and for illusory representations of the population variance. We are testing generalization to other dimensions such as color, motion and orientation Focused attention in feature binding is tested by varying the structural organization of the display, and testing the use of advance information in search. We are also exploring cross-modal binding of visual and auditory stimuli and the role of attention in forming integral representations, again using fMRI to localize the relevant brain areas. Within vision we are testing different aspects of the binding task, distinguishing spatial scanning, suppression of distractors and feature integration. A third series of experiments explores the maintenance of binding in visual working memory, looking at the retention of object representations for short periods after they disappear, comparing the retention of features and of their bindings and exploring capacity limits and vulnerability to interference. The last project analyzes different components of control in switching attention between different attributes of an object - what could be called an ”unbinding problem”. We use speeded classification paradigms to identify sources of interference and the components of control and to locate them in the brain through fMRI.
Replies to the question about visual attention and memory should help to determine the architecture of the systems underlying performance in many real world tasks. They may also provide some understanding of how they fail in normal people in conditions of overload, or in patients with brain injuries causing neglect or Balint’s syndrome.
Contact:
Anne Treisman