Guided search for triple conjunctions

A key tenet of feature integration theory and of related theories such as guided search (GS) is that the binding of basic features requires attention. This would seem to predict that conjunctions of features of objects that have not been attended should not influence search. However, Found (1998) reported that an irrelevant feature (size) improved the efficiency of search for a Color × Orientation conjunction if it was correlated with the other two features across the display, as compared to the case in which size was not correlated with color and orientation features. We examined this issue with somewhat different stimuli. We used triple conjunctions of color, orientation, and shape (e.g., search for a red, vertical, oval-shaped item). This allowed us to manipulate the number of features that each distractor shared with the target (sharing) and it allowed us to vary the total number of distractor types (and, thus, the number of groups of identical items: grouping). We found that these triple conjunction searches were generally very efficient—producing very shallow Reaction Time × Set Size slopes, consistent with strong guidance by basic features. Nevertheless, both of the variables, sharing and grouping, modulated performance. These influences were not predicted by previous accounts of GS; however, both can be accommodated in a GS framework. Alternatively, it is possible, though not necessary, to see these effects as evidence for “preattentive binding” of conjunctions.     

Visual motion shifts saccade targets

Saccades are made thousands of times a day and are the principal means of localizing objects in our environment. However, the saccade system faces the challenge of accurately localizing objects as they are constantly moving relative to the eye and head. Any delays in processing could cause errors in saccadic localization. To compensate for these delays, the saccade system might use one or more sources of information to predict future target locations, including changes in position of the object over time, or its motion. Another possibility is that motion influences the represented position of the object for saccadic targeting, without requiring an actual change in target position. We tested whether the saccade system can use motion-induced position shifts to update the represented spatial location of a saccade target, by using static drifting Gabor patches with either a soft or a hard aperture as saccade targets. In both conditions, the aperture always remained at a fixed retinal location. The soft aperture Gabor patch resulted in an illusory position shift, whereas the hard aperture stimulus maintained the motion signals but resulted in a smaller illusory position shift. Thus, motion energy and target location were equated, but a position shift was generated in only one condition. We measured saccadic localization of these targets and found that saccades were indeed shifted, but only with a soft-aperture Gabor patch. Our results suggest that motion shifts the programmed locations of saccade targets, and this remapped location guides saccadic localization.     

Introduction to the special issue on visual working memory

Visual working memory is a volatile, limited-capacity memory that appears to play an important role in our impression of a visual world that is continuous in time. It also mediates between the contents of the mind and the contents of that visual world. Research on visual working memory has become increasingly prominent in recent years. The articles in this special issue of Attention, Perception, & Psychophysics describe new empirical findings and theoretical understandings of the topic.     

Searching while loaded: Visual working memory does not interfere with hybrid search efficiency but hybrid search uses working memory capacity

In “hybrid search” tasks, such as finding items on a grocery list, one must search the scene for targets while also searching the list in memory. How is the representation of a visual item compared with the representations of items in the memory set? Predominant theories would propose a role for visual working memory (VWM) either as the site of the comparison or as a conduit between visual and memory systems. In seven experiments, we loaded VWM in different ways and found little or no effect on hybrid search performance. However, the presence of a hybrid search task did reduce the measured capacity of VWM by a constant amount regardless of the size of the memory or visual sets. These data are broadly consistent with an account in which VWM must dedicate a fixed amount of its capacity to passing visual representations to long-term memory for comparison to the items in the memory set. The data cast doubt on models in which the search template resides in VWM or where memory set item representations are moved from LTM through VWM to earlier areas for comparison to visual items.     

Training Young Adult Peers in a Mobile Motivational Interviewing‐Based Mentoring Approach to Upstream HIV Prevention

Mentoring relationships are characterized by a sustained, high quality, and skill‐building relationship between a protégé and mentor (Handbook of Youth Mentoring, Los Angeles, SAGE, 2014). Within prevention science, youth mentoring programs emphasize creating a specific context that benefits a young person. Program‐sponsored relationships between youth and adults allow for creating a mentor–mentee partnership, but do not require the establishment of a strong bond in order to deliver prevention‐focused activities and experiences (Handbook of Youth Mentoring, Los Angeles, SAGE, 2014). Motivational Interviewing (MI) is a counseling style used widely to promote health behavior change and in prevention interventions. As part of an upstream approach to HIV prevention, we combined mentoring and MI by training peer mentors to use MI skills in their interactions as part of a large RCT of a mobile life skills intervention for adolescent men who have sex with men (AMSM). Our training model developed for training peer mentors in MI skills resulted in peers reaching and exceeding established MI fidelity thresholds (e.g., mean percentage of complex reflections = 80%, mean reflection to question ratio = 2.2:1). We offer reflections on lessons learned and future directions for those researchers and practitioners who may benefit from adapting this blended approach for mentoring AMSM.     

Examining the Link Between the Human Microbiome and Antisocial Behavior: Why Criminologists Should Care About Biochemistry,Too

Objective: The expansion of technology enables closer examination of human biological functioning which has exponentially increased knowledge about how the human organism interacts with surrounding environs to produce certain behaviors. The contemporary biosocial model pushes crime theorists and researchers alike to consider the many biological factors that may be implicated in violent behavior and how those factors are ameliorated or exacerbated by environmental influences (and vice versa). This paper describes the human microbiome and discusses why and how the human microbiome should be incorporated into biosocial investigations of violent behavior.

Method: To date, a fairly significant knowledge-base has accumulated regarding the evolutionary, genetic, and sociological bases of violent behavior but has not yet carefully considered other factors related to biochemistry: namely, the microbiome. We review the emerging literature on the role of the microbiome on phenotypes––particularly antisocial behavior––and synthesize the contribution of this literature to the study of antisocial behavior.

Results: The microbiome is likely an important contributor to animal and human behavior. Recent studies show that the microbiome holds promise in explaining antisocial behavior among a wide range of species including humans.

Conclusion: Criminological theory and public policy can incorporate knowledge about the microbiome in the explanation of violent behavior, and prevention and intervention efforts.     

On Judgments of Approximately Equal

Although precision is often important in quantitative judgment, sometimes, it is valuable to recognize that two quantities are roughly the same. Fuzzy‐trace theory suggests that approximately equal judgments rely on gist representations (i.e., meaningful fuzzy categories of quantity). We conducted three experiments to investigate approximately equal judgments with number pairs presented in different formats, both with and without semantic content (breast cancer statistics). In each study, the ratio of the smaller divided by larger number predicted approximately equal judgments. Experiment 1 also examined how knowledge of breast cancer, presentation format (frequencies vs. percentages), and differences in gist comprehension of breast cancer information influence fuzzy equality judgments. As predicted by the fuzzy‐trace theory concept of denominator neglect, approximately equal judgments were more sensitive, as measured by signal detection theory (SDT) analyses, when presented as percentages. In both experiments with breast cancer statistics, people were more likely to judge number pairs approximately equal when they were embedded in sentences about breast cancer, and breast cancer knowledge predicted increased perception of equality, when appropriately consistent with reliable sources, and increased judgment sensitivity. In Experiment 2, a simple intervention focusing on gist meaning increased source‐consistent approximately equal judgments, increased SDT judgment sensitivity, and decreased SDT response bias. In Experiment 3, using number pairs devoid of semantic context spanning four orders of magnitude, we further examined ratio similarity. Overall, more knowledgeable judges and those who better understood the gist of meaningful numbers were more likely to judge literally different numbers as “approximately equal” rather than make precise discriminations that were meaningless. Copyright © 2017 John Wiley & Sons, Ltd.     

Moving towards solutions to some enduring controversies in visual search

How do we find a target item in a visual world filled with distractors? A quarter of a century ago, in her influential 'Feature Integration Theory (FIT)', Treisman proposed a two-stage solution to the problem of visual search: a preattentive stage that could process a limited number of basic features in parallel and an attentive stage that could perform more complex acts of recognition, one object at a time. The theory posed a series of problems. What is the nature of that preattentive stage? How do serial and parallel processes interact? How does a search unfold over time? Recent work has shed new light on these issues.     

Saved by a log: how do humans perform hybrid visual and memory search?

Could you find 1 of your 1,000 Facebook friends in a crowd of 100? Even at a rate of 25 ms per comparison, determining that no friends were in the crowd would take more than 40 min if memory and visual search interacted linearly. In the experiment reported here, observers memorized pictures of 1 to 100 targets and then searched for any of these targets in visual displays of 1 to 16 objects. Response times varied linearly with visual set size but logarithmically with memory set size. Data from memory set sizes of 1 through 16 accurately predicted response times for different observers holding 100 objects in memory. The results would be consistent with a binary coding of visual objects in memory and are relevant to applied searches in which experts look for any of many items of interest (e.g., a radiologist running through a mental checklist of what might be wrong in a car-crash victim or an airport screener looking for any of a list of prohibited items in a carry-on bag).