Many are finding it hard to concentrate after television viewing of reports of the aftermath of hijackings of four U.S. airlines that killed thousands of Americans and destroyed foundations of the American landscape. Memories of the images of planes crashing into the World Trade Center, people leaping out of the WTC buildings and the pentagon on fire are staying with people. The reason people can't shift their attention back so easily to their normal routines, say experts on anxiety and visual attention, is that threatening images hold our attention much longer than non-threatening ones, especially for those who were feeling anxious before the attacks.

Humans have an adaptive element which keeps us focused on threatening images, say researchers from the University of Essex in England who conducted experiments to show the link between anxiety and attention bias of threatening stimuli. "A delay in disengagement to threatening stimuli allows animals and humans to conduct a more detailed cognitive processing of potential threats in their environment. This attention bias might have evolved to protect us from attack by other animals centuries ago," said lead author Elaine Fox, Ph.D., and colleagues.

According to their study on anxiety and visual attention, published in an American Psychological Association journal, appear people with heightened anxiety who are exposed to threatening stimuli may find it increasingly difficult to concentrate on anything but the threatening images. Attention is not only more quickly drawn to threatening stimuli for people who are anxious than for people who are not, but anxious people have trouble disengaging their attention from threatening visual images, explain the authors.

In five experiments, 282 college students and staff from the University of Essex aged 17 to 60 participated in the Stroop and dot-probe procedures to measure how threatening stimuli influence visual attention. Both methods, which are widely used, have participants view threat-related or negative stimuli and neutral visual stimuli at the same time. The participants are asked to attend to one while ignoring the other. All the participants included in these experiments were not experiencing clinical levels of anxiety, but some were experiencing subclinical levels of anxiety measured by an anxiety scale.

"These experiments are evidence that anxious people are not just shifting their attention toward the location of threat," said Fox. "They may be unable to disengage their attention to a noticed threat as quickly."

The experiments used in the study used a procedure developed by University of Washington psychologist Michael I. Posner, Ph.D., and colleagues, known as "exogenous cueing". The procedure provides a test of visual attention that - unlike other measures - distinguishes between two components of attention: attentional shift and attentional disengagement.

This "exogenous cueing" procedure involved several hundred trials of viewing a small circle briefly presented on either the left or right side of a computer screen. Participants were asked to indicate by pressing one of two keys which side of the screen the circle had appeared. On each trial, presentation of the circle was preceded by a "cue" stimulus, which sometimes appeared on the same side or opposite side of the screen. In some of the experiments, the cues were threatening, positive or neutral words, and in some of the experiments, the cues were angry, happy or neutral faces.

The participants' response speeds on the so-called "invalid" trials in which the target circle appeared on the opposite side of the screen from the cue was particularly telling about attention bias, said the authors. "It required the participants to withdraw their attention from the cue and transfer it to the opposite side of the screen. So if anxiety is associated with an impaired ability to disengage from threatening stimuli, then anxious participants would be slower to respond on invalid trials when they had been cued with threatening stimuli - fear provoking words or angry faces - than when they had been cued with neutral or positive stimuli. This is exactly what we found," said Fox.

Furthermore, we found that no such attention bias occurred for non-anxious participants, which supports our hypothesis that "those with anxiety at the subclinical levels and those with more intense anxiety have a decreased ability to disengage from threatening stimuli. We must now find out if this attention bias is associated with the chronic worrying and rumination that people with diagnosable anxiety disorders often experience," said the authors.

Our findings provide us with valuable information that could enable us to "train those suffering from anxiety to quickly shift their attention away from threatening stimuli, potentially reducing the attention bias and ultimately preventing the anxiety," said Fox.

Article: "Do Threatening Stimuli Draw of Hold Visual Attention in Subclinical Anxiety?" Elaine Fox, Ph.D., Riccardo Russo, Ph.D., Robert Bowles, Ph.D., and Kevin Dutton, Ph.D., University of Essex; Journal of Experimental Psychology: General, Vol 130, No. 4.

10/04/01

Elaine Fox, PhD can be reached by telephone at +44 1206 873783