Perceptual visual grouping under inattention: electrophysiological functional imaging

Two types of perceptual visual grouping, differing in complexity of shape formation, were examined under inattention. Fourteen participants performed a similarity judgment task concerning two successive briefly presented central targets surrounded by task-irrelevant simple and complex grouping patterns. Event-related potentials (ERPs) were recorded from 22 scalp electrodes and source current density estimations were conducted for the net response to the task-irrelevant background patterns, using low-resolution electromagnetic tomography (LORETA). Although participants’ subjective reports indicated that neither type of organization induced awareness, electrophysiological results showed they both evoked significant activation in occipital, parieto-temporal and frontal brain areas. Behavioral results demonstrated that only grouping of the simple pattern arose under inattention. In contrast to the complex pattern, the processing of the simple pattern was associated with an initially longer latency and higher activation beginning at 130 ms. These results support the distinction of grouping patterns differing in complexity of shape formation.     

The effects of perceptual load on semantic processing under inattention

Inattentional blindness refers to a failure to consciously detect an irrelevant object that appears without any expectation when attention is engaged with another task. The perceptual load theory predicts that task-irrelevant stimuli will reach awareness only when the primary task is of low load, which allows processing resources to spill over to processing task-irrelevant stimuli as well. We studied whether perceptual load has an effect on inattentional blindness for a task-irrelevant stimulus whose meaning is or is not relevant to the attentional goals of the observer. In the critical trial, a word appeared without any expectation in the center of a display of attended pictures. The results showed that, under both high and low load, unexpected words belonging to the attended semantic category were detected more often than semantically unrelated words. These results imply that task-irrelevant stimuli, whose meanings are relevant to the observer’s task, enter awareness irrespective of perceptual load.     

Forbidden fruit: inattention to attractive alternatives provokes implicit relationship reactance

Being inattentive to attractive relationship alternatives can enhance relationship well-being. The current investigation, however, demonstrates that implicitly preventing people from attending to desirable relationship alternatives may undermine, rather than bolster, the strength of that person's romantic relationship. Consistent with the notion of "forbidden fruit," we found that subtly limiting people's attention to attractive alternatives reduced relationship satisfaction and commitment and increased positive attitudes toward infidelity (Experiment 1), increased memory for attractive relationship alternatives (Experiment 2), and increased attention to attractive alternatives (Experiment 3). Findings suggest that although attention to attractive alternatives can harm one's relationship, situations that implicitly limit one's attention to alternatives can, rather ironically, increase the temptation of alternatives and undermine relationship well-being.     

Adaptation to optically-increased interocular separation under naturalistic viewing conditions

Mirror spectacles which enhance binocular disparity by optically doubling the normal separation between the eyes were used to create conditions of combined perceptual and oculomotor conflict. Apparent depth and distance, as well as tonic accommodation, tonic vergence, and accommodative-vergence gain (response AC/A ratio), were assessed immediately before and after a 30 min exposure period of naturalistic viewing with the spectacles. Wearing the spectacles produced an increase in tonic vergence, and perceptual aftereffects consisting of increased apparent distance and depth. The results indicate that oculomotor conflict associated with enhanced interocular separation may be resolved through adaptation of tonic vergence, rather than through alteration of accommodative-vergence gain. The results also demonstrate that perceptual conflict between disparity and multiple veridical depth cues does not necessarily produce adaptive modification of the relationship between binocular disparity and apparent depth.