Anne Treisman

Born: 27 February 1935 Wakefield, Yorkshire, England
Residence: New York City, United States
Known for: Feature integration theory, Attenuation theory
Notable awards: National Medal of Science (2011)

Anne Marie Treisman is a psychologist currently at Princeton University's Department of Psychology. She researches visual attention, object perception, and memory. One of her most influential ideas is the feature integration theory of attention, first published with G. Gelade in 1980. Treisman has taught at Oxford, University of British Columbia, University of California, Berkeley and Princeton. In 2013, Treisman received the National Medal of Science from President Barack Obama for her pioneering work in the study of attention. During her long career, Treisman has experimentally and theoretically defined the issue of how information is selected and integrated to form meaningful objects that guide human thought and action.

Feature Integration Theory

Treisman's Feature Integration Theory proposes a two-stage model of object perception:

Pre-Attentive Stage

The first stage is called “pre-attentive” because it happens automatically, or without effort or attention by the perceiver. In this stage, an object is broken down into its elementary features for processing (i.e., color, texture, shape, etc.). Treisman posits we are unaware of this stage of attention because it occurs quickly and early in perceptual processes (before conscious awareness). Evidence for the pre-attentive state comes from Treisman's own studies. Treisman created a display of four objects flanked by two black numbers. The display flashed on a computer screen for 1/5 of a second and followed by a random-dot masking field to eliminate residual perception of the stimuli after the stimuli were turned off. Participants were asked to first report on the black numbers, followed by what they saw at each of the four locations where the shapes had been. Under these conditions, participants reported seeing illusory conjunctions in 18% of trials. That is, participants reported seeing objects that consisted of a combination of features from two different stimuli. For example, after seeing a big yellow circle, a big blue triangle, a small red triangle, and a small green circle, a person might report seeing a small red circle and a small green triangle. The reason illusory conjunctions occurred is that stimuli were presented rapidly and the observers' attention was distracted from the target object by having them focus on the black numbers; thus, elementary features had not yet been grouped or bound to an object. Having participants attend to the target objects eliminated the illusory conjunction

Focused Attention Stage

The second stage of processing depends on attention. In this stage, the features are recombined, so we perceive the whole object rather than individual features.
Treisman links the process of binding that occurs in the focused attention stage to physiology by noting that an object causes activity in both the '’what'’ and '’where'’ streams of the cortex (see Two-streams hypothesis). Activity in the '’what'’ stream would include information about color and form, while activity in the '’where'’ stream would include information about location and motion. According to Treisman, attention is the "glue" that combines the information from both streams and causes us to perceive all the features of an object as combined at one specific location. It is easy to consider perceiving one object in isolation, but when we consider multiple objects, numerous features exist at many locations. The perceptual system's task is to associate each of these features with the object to which it belongs. Feature integration theory proposes that in order for this to occur, we need to focus our attention on each object in turn. Once we attend to a particular location, the features at that location are bound together and are associated with the object at that location.
Treisman repeated the illusory conjunction experiment, but now instructed participants to ignore the flanking numbers and focus their attention on the four target objects. Focused attention eliminated illusory conjunctions.
Treisman's FIT model now uses three different spatially selective mechanisms to solve the binding problem: selection by a spatial attention window, inhibition of locations from feature maps containing unwanted features, and top-down activation of the location containing the currently attended object.

Impact

William James discussed the connection between attention and mental processes, "Millions of items…are present to my senses which never properly enter my experience. Why? Because they have no interest for me. My experience is what I agree to attend to…Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought…It implies withdrawal from some things in order to deal effectively with others.^"
In the early 1980s, neuroscientists such as Torston Wiesel and David H. Hubel were discovering that different areas of the primate visual cortex were finely tuned to selective features, such as line orientation, luminance, color, movement, etc. These findings prompted the question of how these distinct features are connected into a unified whole, e.g., the binding problem. For example, when you see a red ball roll by, cells sensitive to movement fire in the medial temporal cortex, while cells sensitive to color, shape and location fire in other areas. Despite all this distinct neuronal firing, you don't perceive the ball as separated by shape, movement and color perceptions; you experience an integrated experience with all these components occurring together. The question of how these elements are combined is the essence of the binding problem and continued into the late 1990s. A number of possible mechanisms were envisaged, including grandmother cells responding to specific conjunctions of features that uniquely identify a particular object; local cell assemblies onto which the pathways from different feature maps converge, perhaps with adjustable connections allowing flexible routing of signals; a serial scan of different spatial areas selected by an adjustable attention window, conjoining the features that each contains and excluding features from adjacent areas;^[10] detection of temporal contiguity – parts and properties whose onset, offset or motion coincide probably belong to the same object synchronised firing of cells responding to features of the same object, perhaps assisted by oscillatory neural activity. Treisman used failures of binding to shed light on its underlying mechanisms. Specifically, she found that left-brain-damaged patients have increasing illusory conjunctions and decreased performance in a spatially cued attention task, which suggests a link between attentional binding and the parietal lobes. Treisman also cited corroborating evidence from positron emission tomography and event-related potential studies which were consistent with the spatial attention account of feature integration.
Treisman's work has formed the basis for thousands of experiments in cognitive psychology, vision sciences, cognitive science, neuropsychology and cognitive neuroscience.

Honors

Treisman was elected to the Royal Society of London in 1989, the US National Academy of Sciences in 1994, and the American Academy of Arts and Sciences in 1995, as well as a William James Fellow of the American Psychological Society in 2002. Treisman was the recipient of the 2009 University of Louisville Grawemeyer Award in Psychology for her explanation of how our brains build meaningful images from what we see.