Anomalous global effects induced by ‘blind’ distractors in visual hemifield defects

Previous research has revealed that a stimulus presented in the blind visual field of participants with visual hemifield defects can evoke oculomotor competition, in the absence of awareness. Here we studied three cases to determine whether a distractor in a blind hemifield would be capable of inducing a global effect, a shift of saccade endpoint when target and distractor are close to each other, in participants with lesions of the optic radiations or striate cortex. We found that blind field distractors significantly shifted saccadic endpoints in two of three participants with lesions of either the striate cortex or distal optic radiations. The direction of the effect was paradoxical, however, in that saccadic endpoints shifted away from blind field distractors, whereas endpoints shifted towards distractors in the visible hemifields, which is the normal global effect. These results provide further evidence that elements presented in the blind visual field can generate modulatory interactions in the oculomotor system, which may differ from interactions in normal vision.     

Primary shame,mortal wound and tragic circularity: Some new reflections on shame and shame conflicts

Invited to contribute some thoughts on recent developments in psychoanalytic thinking about shame, the author starts off with Aristotle's prescient analysis of shame and then focuses on accumulating experiences in the psychoanalytic treatment of patients with severe neuroses, in particular the close relationship of severe traumatization and chronic states of shame, and how this is reflected in shelfdestructive repetitions. Reminiscent of what we know from tragedy and the tragic dimension of human existence, this repetition compulsion shows a built‐in circularity. These circular dynamics have at their core struggles with deep woundedness that can variably be conceived of as primary pain, primary shame and primary anxiety. Consequently, throughout the experiences with these patients goes the absoluteness both of their conscience and of their ideal, what we know as the “archaic superego:”     

Space-based and object-based capacity limitations in visual search

Space-based accounts of visual attention assume that we select a limited spatial region independent of the number of objects it contains. In contrast, object-based accounts suggest that we select objects independent of their location. We investigated the boundary conditions on the selection modes of attention in a series of tachistoscopic visual search tasks, where the nature of capacity limitations on search was examined. Observers had to search for a horizontally oriented target ellipse among differently oriented distractor ellipses. Across four experiments, we orthogonally manipulated target-distractor (TD) similarity and distractor-distractor (DD) similarity. Each experiment consisted of a two-way design: Firstly, with a central cue, we indicated the spatial extent of the relevant search area. Secondly, we varied the number and spatial proximity of items in the display. Performance could be accounted for in terms of capacity limited object-based attention, assuming also that the spatial proximity of items enhances performance when there is high DD-similarity (and grouping). In addition, the cueing effect interacted with spatial proximity when DD-similarity was high, suggesting that grouping was influenced by attention. We propose that any capacity limits on visual search are due to object-based attention, and that the formation of perceptual objects and object groups is also subject to attentional modulation.     

Sustained attention can create an (illusory) experience of seeing dynamic change

Recent studies speculated that two types of change detection exist, one involving the experience of seeing dynamic change (change over brief interval), the other involving detecting a completed change (change over long interval), with only the former requiring sustained attention. To examine this supposition, a flicker change detection task was conducted in which the spatial location of objects was manipulated (shift, no-shift). In shift conditions, changed image display appeared in different locations than they did in the original display. The time interval separating images was manipulated (200 or 1000 ms). Results showed that a shift led to poor change detection only in the short interval condition. The performance decline by the image shift was not attenuated even when participants knew beforehand whether or not a shift would occur. Results indicate that sustained attention, which is sustained for a brief time, is related to the experience of seeing dynamic change.     

Visual distraction increases the detection of an unexpected object in inattentional blindness

Distraction is typically thought to be detrimental to performance and concentration, and stimuli are classified as “distractions” if they take attention away from a primary task. However it has been shown that, under certain circumstances, distractors can also improve task performance. The current study extends this literature by exploring the role of a single discrete transient visual distracting event in increasing attention to an unexpected visual object in an inattentional blindness (IB) paradigm. Experiment 1 investigated the impact of a 48 ms visual distraction stimulus on rates of IB; a second experiment used a shortened, 16 ms visual distracting event. Both the long 48 ms and brief 16 ms distractors significantly reduced overall IB rates, by approximately 50% compared to a no distractor condition. Moreover, this reduction in IB is obtained independent of whether the visual distracting event was noted by the observer. Our findings demonstrate that a single discrete visual distraction can improve the detectability of an unexpected object in an IB task. Implications for theories of distributed attention in such tasks are discussed.     

Visual symmetry perception in early onset monocular blindness

Symmetry detection is impaired by abnormal binocular vision development such as in amblyopia. However, the detection of symmetry has never been investigated in cases where input from one eye is profoundly compromised. Testing monocularly blind (MB) individuals represents a unique opportunity to investigate whether symmetry salience relies on a normally developed binocular visual system. In a visual symmetry detection task using dot patterns, congenitally MB showed comparable accuracy to normally sighted individuals viewing monocularly. This included better detection of vertically than horizontally symmetric patterns. However, the MB were slower than controls in detecting a symmetrical pattern. In a control target-detection task, no significant differences in performance were observed between these groups. Overall, normal developing binocular vision does not appear necessary for the visual system to detect the presence of visual symmetry. However, optimal detection mechanisms may be dependent on binocular summation or other processes dependent on input from both eyes.     

Change Blindness and Eyewitness Testimony

The authors explored the relevance of research on change blindness to eyewitness identification and testimony under intentional and incidental memory conditions. Participants (N = 80, 40 men and 40 women) viewed a video enactment of a burglary in which the identity of the burglar changed at the halfway point of the film. Half of participants were briefed to remember the content, and the other half were not. All were tested for the recall of the content, awareness of the change, and ability to identify either or both of the burglars. Some 61% of participants did not notice the identity change. Rates of detection were significantly higher in participants in the intentional condition, who also recalled significantly more detail from the film. Awareness of change was also significantly related to content recall scores and accuracy of identification of both burglars. The results illustrate the interrelation between the eyewitness and change blindness literatures.     

Preferential processing of threatening facial expressions using the repetition blindness paradigm

Background: Neuroanatomical evidence suggests that the human brain has dedicated pathways to rapidly process threatening stimuli. This processing bias for threat was examined using the repetition blindness (RB) paradigm. RB (i.e., failure to report the second instance of an identical stimulus rapidly following the first) has been established for words, objects and faces but not, to date, facial expressions. Methods: 78 (Study 1) and 62 (Study 2) participants identified repeated and different, threatening and non-threatening emotional facial expressions in rapid serial visual presentation (RSVP) streams. Results: In Study 1, repeated facial expressions produced more RB than different expressions. RB was attenuated for threatening expressions. In Study 2, attenuation of RB for threatening expressions was replicated. Additionally, semantically related but non-identical threatening expressions reduced RB relative to non-threatening stimuli. Conclusions: These findings suggest that the threat bias is apparent in the temporal processing of facial expressions, and expands the RB paradigm by demonstrating that identical facial expressions are susceptible to the effect.     

Dissociation of processing time and awareness by the inattentional blindness paradigm

Consciousness researchers are interested in distinguishing between mental activity that occurs with and without awareness (i.e., explicit versus implicit processes). The inattentional blindness (IB) paradigm is an excellent tool for this question because it permits the independent manipulation of processing time and awareness. In the present study, we show that implicit texture segregation can occur during inattentional blindness, provided that the texture is exposed for a sufficient duration. In contrast, a Simon effect does not occur during inattentional blindness, even with similar exposure duration of the critical stimulus. This reveals a dissociation between processing time and awareness, consistent with the possibility of separate processing streams for explicit and implicit visual perception.     

Scene structure enhances change detection

Theories of objects recognition, scene perception, and neural representation of scenes imply that jumbling a coherent scene should reduce change detection. However, evidence from the change detection literature questions whether jumbling affects change detection. The experiments reported here demonstrate that jumbling does, in fact, reduce change detection. In Experiments 1 and 2, change detection was better for normal scenes than for jumbled scenes. In Experiment 3, inversion failed to interfere with change detection, demonstrating that the disruption of surface and object continuity inherent to jumbling is responsible for reduced change detection. These findings provide a crucial commonality between change detection research and theories of scene perception and neural representation. We also discuss why previous research may have failed to find effects of jumbling.