Visual search for changes in scenes creates long-term,incidental memory traces

Humans are very good at remembering large numbers of scenes over substantial periods of time. But how good are they at remembering changes to scenes? In this study, we tested scene memory and change detection two weeks after initial scene learning. In Experiments 1–3, scenes were learned incidentally during visual search for change. In Experiment 4, observers explicitly memorized scenes. At test, after two weeks observers were asked to discriminate old from new scenes, to recall a change that they had detected in the study phase, or to detect a newly introduced change in the memorization experiment. Next, they performed a change detection task, usually looking for the same change as in the study period. Scene recognition memory was found to be similar in all experiments, regardless of the study task. In Experiment 1, more difficult change detection produced better scene memory. Experiments 2 and 3 supported a “depth-of-processing” account for the effects of initial search and change detection on incidental memory for scenes. Of most interest, change detection was faster during the test phase than during the study phase, even when the observer had no explicit memory of having found that change previously. This result was replicated in two of our three change detection experiments. We conclude that scenes can be encoded incidentally as well as explicitly and that changes in those scenes can leave measurable traces even if they are not explicitly recalled.     

Materialism and ‘the soft substance of the brain’: Diderot and plasticity

ABSTRACT

Materialism is the view that everything that is real is material or is the product of material processes. It tends to take either a ‘cosmological’ form, as a claim about the ultimate nature of the world, or a more specific ‘psychological’ form, detailing how mental processes are brain processes. I focus on the second, psychological or cerebral form of materialism. In the mid-to-late eighteenth century, the French materialist philosopher Denis Diderot was one of the first to notice that any self-respecting materialist had to address the question of the status and functional role of the brain, and its relation to our mental life. After this the topic grew stale, with knee-jerk reiterations of ‘psychophysical identity’ in the nineteenth-century, and equally rigid assertions of anti-materialism. In 1960s philosophy of mind, brain–mind materialism reemerged as ‘identity theory’, focusing on the identity between mental processes and cerebral processes. In contrast, Diderot’s cerebral materialism allows for a more culturally sedimented sense of the brain, which he described in his late Elements of Physiology as a ‘book – except it is a book which reads itself’. Diderot thus provides a lesson for materialism as it reflects on the status of the brain, science and culture.     

An evaluation of the agreement between the conservative dual‐criterion method and expert visual analysis

The conservative dual‐criterion (CDC) method was developed to standardize the analysis of single‐subject experimental designs data, but to date its accuracy has been evaluated only by comparing results to the statistical parameters of graphs. Our study investigated agreement between expert visual analysts and the CDC method on 66 AB tiers from published multiple baseline graphs. We found strong agreement between the two methods for certain types of graphs and discuss implications of the findings and areas for future research.     

Does contextual cuing guide the deployment of attention?

Contextual cuing experiments show that when displays are repeated, reaction times to find a target decrease over time even when observers are not aware of the repetition. It has been thought that the context of the display guides attention to the target. The authors tested this hypothesis by comparing the effects of guidance in a standard search task with the effects of contextual cuing. First, in standard search, an improvement in guidance causes search slopes (derived from Reaction Time x Set Size functions) to decrease. In contrast, the authors found that search slopes in contextual cuing did not become more efficient over time (Experiment 1). Second, when guidance was optimal (e.g., in easy feature search), they still found a small but reliable contextual cuing effect (Experiments 2a and 2b), suggesting that other factors, such as response selection, contribute to the effect. Experiment 3 supported this hypothesis by showing that the contextual cuing effect disappeared when the authors added interference to the response selection process. Overall, the data suggest that the relationship between guidance and contextual cuing is weak and that response selection can account for part of the effect.     

The integration of cognition and emotion during infancy and early childhood: regulatory processes associated with the development of working memory

This study was an attempt to integrate cognitive development (i.e., cognitive control) and emotional development (i.e., emotion regulation) in the first years of life. The construct of temperament was used to unify cognition and emotion because of its focus on attentional and regulatory behaviors. Children were seen at 8 months and 412-years of age in a study designed to examine the correlates of working memory development. Frontal brain electrical activity and temperament predicted working memory performance at 8 months. Similarly, frontal brain electrical activity, temperament, and language predicted working memory at age 412-years. Temperament in early childhood mediated the relation between infant temperament and early childhood working memory performance. These associated temperament characteristics highlight the value of early-learned regulatory and attentional behaviors and the impact of these early skills on later development.     

Visual search for type of motion is based on simple motion primitives

Can we search for items based on their type of motion? We consider here visual search based on three types of motion: (i) ballistic motion, in which objects move in a straight line until they encounter a display boundary; (ii) random-walk motion, in which objects change direction randomly; (iii) composite motion, in which objects move with random fluctuations around a generally ballistic trajectory. The asymmetric pattern of search efficiency can be explained by assuming that visual attention is guided by processes sensitive to the presence of linear motion and change in motion. The results do not reveal a more sophisticated ability to segregate items based on the nature of their motion.     

Fixational eye movements are not an index of covert attention

The debate about the nature of fixational eye movements has revived recently with the claim that microsaccades reflect the direction of attentional shifts. A number of studies have shown an association between the direction of attentional cues and the direction of microsaccades. We sought to determine whether microsaccades in attentional tasks are causally related to behavior. Is reaction time (RT) faster when microsaccades point toward the target than when they point in the opposite direction? We used a dual-Purkinje-image eyetracker to measure gaze position while 3 observers (2 of the authors, 1 naive observer) performed an attentional cuing task under three different response conditions: saccadic localization, manual localization, and manual detection. Critical trials were those on which microsaccades moved away from the cue. On these trials, RTs were slower when microsaccades were oriented toward the target than when they were oriented away from the target. We obtained similar results for direction of drift. Cues, not fixational eye movements, predicted behavior.     

Psychological distress associated with domestic violence in Northern Ireland

Several studies have noted an association between domestic violence and psychological distress. However, little empirical work has examined behavioral and psychological difficulties, especially with reference to dissociation and guilt, in victims of domestic violence in Northern Ireland. In addition, childhood abuse history has tended not to be assessed in studies conducted in the Province. Using measures designed to assess behavioral and psychological difficulties that are problematic to self and/or others (that is, Brief Symptoms Inventory, General Health Questionnaire, Guilt Inventory), dissociation (that is, Dissociative Experiences Scale, Peritraumatic Dissociative Experiences Questionnaire) and trauma (that is, Traumatic Experiences Checklist), the current study assessed Northern Irish victims of domestic violence from shelter-type accommodation (N=33) and a comparison sample of women from the general population (N=33). The domestic violence group displayed significantly more psychological difficulties, including higher depression, anxiety and dissociation scores. Dissociative episodes at the time of an assault were related to higher on-going dissociative experiences. Finally, the domestic violence sample reported more emotional, physical, and sexual abuse in childhood than the comparison group. Despite the difficulty generalizing from victims of domestic violence in shelter-type accommodation to all victims of spousal abuse, the current results highlight the increased levels of psychological distress in those exposed to abuse by their partner.