Antidepressant drug administration modulates emotional processing in depressed patients very early in treatment, before changes occur in mood and symptoms. This effect may ameliorate the negative biases in information processing that characterize mood and anxiety disorders. It also suggests a mechanism of action compatible with cognitive theories of depression.

Anxiety patients exhibit attentional biases toward threat, which have often been demonstrated as increased distractibility by threatening stimuli. In contrast, speeded detection of threat has rarely been shown. Therefore, the authors studied both phenomena in 3 versions of a visual search task while eye movements were recorded continuously. Spider-fearful individuals and nonanxious control participants participated in a target search task, an odd-one-out search task, and a category search task. Evidence for disorder-specific increased distraction by threat was found in all tasks, whereas speeded threat detection did not occur in the target search task. The implications of these findings for cognitive theories of anxiety are discussed, particularly in relation to the concept of disengagement from threat.

Seven experiments explore the role of bottlenecks in selective attention and access to visual shortterm memory in the failure of observers to identify clearly visible changes in otherwise stable visual displays. Experiment One shows that observers fail to register a color change in an object even if they are cued to the location of the object by a transient at that location as the change is occurring. Experiment Two shows the same for orientation change. In Experiments Three and Four, attention is directed to specific objects prior to making changes in those objects. Observers have only a very limited memory for the status of recently attended items. Experiment Five reveals that observers have no ability to detect changes that happen after attention has been directed to an object and before attention returns to that object. In Experiment Six, attention is cued at rates that more closely resemble natural rates and Experiment Seven uses natural images. Memory capacity remains very small (<4 items).If you ask typical observers, outside of a vision research laboratory, what they are seeing right now, they will probably tell you that they are seeing a large number of objects placed in a spatially continuous scene. If you ask them if they are seeing all of that at the same time, they will look at you quizzically but they will agree that all of the objects seem to be visually present in the present instant of time. It hardly seems like much of a question. However, if you ask atypical observers, those who have been studying the question over the past 20 years or so, the answers may be quite different. A range of phenomena suggest that human observers are unable to perform tasks that would seem to be quite trivial if we could see what was in front of our eyes in the uncomplicated manner suggested by naïve introspection.Change blindness is one of the most striking of these phenomena. In a typical change blindness paradigm, the observer is told to monitor an image for a change. As long as transients are masked and as long as the observer is not attending to the object that is changing, observers will be very poor at detecting quite substantial changes. These can range from changes to significant objects in natural scenes to changes in "basic features" like color (Phillips, 1974;Rensink, O'Regan, & Clark, 1997;Simons, 2000;Simons & Levin, 1997).Similar failures to report what is in front of the eyes occur when observers are attending to one aspect of a display and subsequently queried about another. Thus, Mack and Rock (1998) found that observers who were answering a question about a pair of lines would fail to report salient stimuli presented at fixation ("inattentional blindness"). Simons Neisser & Becklen, 1975) have shown that observers who were monitoring one set of actors would fail to notice other actors (e.g. a woman in a gorilla suit) as they entered and left a scene (Simons & Chabris, 1999).Some have argued that these results demonstrate that we only "see" the current object of attention and that the re...

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These results suggest that 7 days of SSRI administration can increase neural markers of fear reactivity in subjects at the high end of the N dimension and may be related to early increases in anxiety and agitation seen early in treatment. Such processes may be involved in the later therapeutic effects through decreased avoidance and increased learning about social 'threat' cues.