Perception of Objects in Natural Scenes: Is It Really Attention Free?

Studies have suggested attention-free semantic processing of natural scenes in which concurrent tasks leave category detection unimpaired (e.g., F. Li, R. VanRullen, C. Koch, & P. Perona, 2002). Could this ability reflect detection of disjunctive feature sets rather than high-level binding? Participants detected an animal target in a rapid serial visual presentation (RSVP) sequence and then reported its identity and location. They frequently failed to identify or to localize targets that they had correctly detected, suggesting that detection was based only on partial processing. Detection of targets was considerably worse in sequences that also contained humans, presumably because of shared features. When 2 targets were presented in RSVP, a prolonged attentional blink appeared that was almost eliminated when both targets were detected without being identified. The results suggest rapid feature analysis mediating detection, followed by attention-demanding binding for identification and localization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sertraline in the treatment of severe aggressiveness in Huntington''s disease

Sertraline, a selective serotonin reuptake inhibitor, was used to treat two consecutive cases of genetically confirmed Huntington's disease in which severe irritability and aggressiveness required inpatient admission. The complete cessation of aggressive behavior in both cases has been maintained on follow-up. This report adds to the literature implicating serotonergic mechanisms in irritability and aggressiveness in both neuropsychiatric and idiopathic psychiatric disorders.     

Relation between signal detectability theory and the traditional procedures for measuring thresholds: An addendum.

Replys to P. Isaac's (see record 1971-01479-001) criticism of the method of analysis used by M. Treisman and T. Watts (see PA, Vol. 41:1034) to support their conclusion that signal-detectability measures could be related to those given by the traditional psychophysical procedures. Reexamination of the data strengthens the original conclusion and reveals a further implication of the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feature binding, attention and object perception

The seemingly effortless ability to perceive meaningful objects in an integrated scene actually depends on complex visual processes. The 'binding problem' concerns the way in which we select and integrate the separate features of objects in the correct combinations. Experiments suggest that attention plays a central role in solving this problem. Some neurological patients show a dramatic breakdown in the ability to see several objects; their deficits suggest a role for the parietal cortex in the binding process. However, indirect measures of priming and interference suggest that more information may be implicitly available than we can consciously access.     

Visual attention and the perception of features and objects.

Feature integration theory (Treisman & Gelade, 1980) suggested that simple features are coded in parallel in a number of specialized feature maps, but that focussed attention is required to ensure the correct integration of features to specify objects. This is done by a serial scan through a master-map of locations, giving access to the features currently occupying the attended location. These are then integrated to form a representation of the object in the selected location. The present paper reviewed new evidence that has accrued since 1980 and elaborated the model to accommodate the recent findings. The proposal is that four different mechanisms may be involved in different conditions: selection of locations, directed by an externally controlled window of attention; selection by features through preattentive grouping; selection of objects; and selection for access to responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the stability of d .

In signal detection theory, the index d -sub(s) is commonly believed to be a more stable measure of discrimination than d ' when the slope of the receiver operating characteristic varies across conditions. The basis for this is examined, and a model is developed that appears to explain both the stability of d -sub(s) and the variation in the slope of the receiver operating characteristic, which may be found when the prior probability of the signal is varied. The model rests on the assumption that sequential influences may affect criterion variance. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)