Beyond the Grand Illusion: What Change Blindness Really Teaches Us About Vision

Experiments on scene perception and change blindness suggest that the visual system does not construct detailed internal models of a scene. These experiments therefore call into doubt the traditional view that vision is a process in which detailed representations of the environment must be constructed. The non-existence of such detailed representations, however, does not entail that we do not perceive the detailed environment. The “grand illusion hypothesis” that our visual world is an illusion rests on (1) a problematic “reconstructionist” conception of vision, and (2) a misconception about the character of perceptual experience.     

Motion influences gaze direction discrimination and disambiguates contradictory luminance cues

In two experiments, we investigated the role of apparent motion in discriminating left/right gaze deviation judgments. We demonstrated that discrimination accuracy and response confidence was significantly higher when the eyes were moved to the left or right, compared to when the eyes were presented in their final shifted position (static images). To dissociate the role of motion signals from luminance signals, gaze stimuli were also presented in reverse contrast. Replicating past studies polarity reversal had a profound and detrimental effect on gaze discrimination in static images, although, intriguingly, while response confidence remained low, participant performance improved as gaze angle increased. In striking contrast to these data, polarity reversal had no negative effect on performance when the eyes were moved. We discuss these findings in the context of a multiple-cue account of gaze perception.     

What is Essential About Indexicals?

Philosophical Studies -     

Secondary traumatic stress in emergency medicine clinicians

Previously called Secondary Traumatic Stress (STS), secondary exposure to trauma is now considered a valid DSM-5 Criterion A stressor for posttraumatic stress disorder (PTSD). Previous studies have found high rates of STS in clinicians who treat traumatically injured patients. However, little research has examined STS among Emergency Medicine (EM) physicians and advanced practice providers (APPs). The current study enrolled EM providers (N = 118) working in one of 10 hospitals to examine risk factors, protective factors, and the prevalence of STS in this understudied population. Most of the participants were physicians (72.9%), Caucasian (85.6%), and male (70.3%) with mean age of 39.7 (SD = 8.9). Overall, 12.7% of the sample screened positive for STS with clinical levels of intrusion, arousal, and avoidance symptom clusters, and 33.9% had at least one symptom cluster at clinical levels. Low resilience and a history of personal trauma were positively associated with positive STS screens and STS severity scores. Borderline significance suggested that female gender and spending ≥10% of one’s time with trauma patients could be additional risk factors. Findings suggest that resilience-building interventions may be beneficial.     

Turn left where you felt unhappy: how affect influences landmark-based wayfinding

The present work investigated the impact of affect in landmark-based wayfinding. We assumed that affect-laden landmarks improve wayfinding performance and have an impact on later landmark recognition. To investigate our hypotheses, we ran two experiments in a virtual maze. In Experiment 1, we investigated how affect-laden landmarks influence wayfinding and recognition in comparison with neutral landmarks. The aim of Experiment 2 was to focus on the affective valence of a landmark. The memory tasks of both experiments were repeated after 1 week in order to assess memory consolidation. Results showed that the best wayfinding and recognition performance occurs when negatively laden landmarks were used. In comparison with neutral and positively laden landmarks, recognition performance hardly decreased over time for the negatively laden landmarks. Our results not only support findings in the field of emotion research but also expand the concept of semantic landmark salience with respect to emotional responses.