A review of implementation intentions as a tool to benefit high-need patients and healthcare systems: U.S. veterans affairs as an exemplar.

Implementation intentions (if-then plans) are an evidence-based behavior change strategy designed to translate behavioral intentions into habits [1]. Despite extensive evidence of its potential utility, this behavior change strategy is underutilized and under-researched in high-need healthcare contexts within the United States (U.S.) which face high rates of chronic conditions and barriers to care such as rurality, lack of resources, and cognitive strain from mental health and neurological conditions [2,3]. Implementation intentions have demonstrated efficacy in promoting many health behaviors proven to mitigate chronic conditions, namely physical activity, healthy diet, and substance use reduction [4-6]. In addition, the accessible, adaptable, and self-driven nature of implementation intentions allow the technique to meet many of the individual and system-level priorities of these high-need care contexts. By being patient-driven, proactive, and personalized, implementation intentions can help these patients cultivate healthy habits as part of their everyday lives. At the systems-level, implementation intentions' inexpensiveness, scalability, and compatibility with telemedicine platforms allow them to be integrated easily into existing healthcare system infrastructure [7,8]. This review describes these concepts in detail, and uses the Veterans Affairs (VA) healthcare system as an exemplar to provide concrete examples of how and where implementation intentions could be integrated in a healthcare system, within some existing programs, to benefit both the system and individual patients.

Which Intervention Strategies Promote the Adoption and Maintenance of Physical Activity? Evidence From Behavioral Trials With Cancer Survivors.

BACKGROUND/PURPOSE: We address four questions about interventions to promote physical activity in cancer survivors: (a) How often is both the adoption and maintenance of behavior change tested in trials? (b) How often do interventions generate adoption-plus-maintenance of behavior change? (c) Are intervention strategies specifically geared at promoting maintenance of behavior change deployed in trials? and (d) Which intervention strategies distinguish trials that promote both the adoption and maintenance of physical activity from trials that promote adoption-only or generate no behavioral changes? METHODS: Computerized literature searches identified 206 reports of randomized trials that measured physical activity in the wake of the intervention. RESULTS: Only 51 reports (24%) measured both behavioral adoption (postintervention) and behavioral maintenance (≥3 months follow-up). The 51 reports included 58 tests of interventions; 22% of tests observed both adoption and maintenance of physical activity, 26% reported adoption-only, and 52% found no change in behavior. Change techniques designed to promote behavioral maintenance were used much less frequently than adoption techniques or adoption and maintenance techniques. Interventions that aimed to improve quality of life, used supervised exercise sessions, were undertaken in community centers, and deployed fewer behavior change techniques were associated with adoption-plus-maintenance of physical activity in cancer survivors. CONCLUSIONS: The present findings offer new insights into the adoption and maintenance of physical activity and highlight the need to routinely assess these forms of behavior change in future trials. More extensive testing of intervention strategies specifically geared at maintenance of behavior change is warranted.

Cancer survivors need to not only adopt, but also maintain, physical activity to benefit their health and wellbeing. We undertook a systematic review of interventions to promote the adoption and maintenance of physical activity in cancer survivors. Out of 206 physical activity interventions for cancer survivors that we identified, only 51 (24%) measured both the adoption and maintenance of behavior change. Of these 51 intervention studies, only 22% were effective in promoting both the adoption and maintenance of physical activity. We developed a new classification of behavior change techniques used in interventions and discovered that techniques specifically designed to promote behavioral maintenance were used only rarely. We found that interventions that aimed to improve quality of life, used supervised exercise sessions, and were undertaken in community centers predicted adoption-plus-maintenance of physical activity in cancer survivors. These findings underscore the need for more trials that assess the adoption and maintenance of physical activity and for new research programs focused on evaluating the efficacy of maintenance techniques.

How Does Self-Control Promote Health Behaviors? A Multi-Behavior Test of Five Potential Pathways.

BACKGROUND: Self-control is generally defined as the capacity to override impulses and is a robust predictor of health behaviors. This paper integrates trait, reasoned action, and habit approaches to develop and test a mechanistic account of how self-control influences health actions. PURPOSE: We tested five potential pathways from self-control to behavior, termed the valuation, prioritization, habituation, translation, and inhibition routes. METHODS: At baseline, participants (N = 663 adults) completed survey measures of reasoned action approach variables and habits in relation to eight health behaviors and the Brief Self-Control Scale. Three months later, participants reported their behavior. Multi-level modeling was used to test pathways across behaviors. RESULTS: Supporting the valuation route, affective attitude, cognitive attitude, descriptive norms, and perceived behavioral control mediated the self-control-intention relation, and intentions and perceived behavioral control mediated the relationship between self-control and health behaviors. Self-control also predicted the priority accorded to different considerations during intention formation. Higher self-control was associated with stronger prediction by cognitive attitudes and perceived behavioral control and weaker prediction by habits and injunctive norms. Self-control predicted habit formation, and habits mediated the self-control-behavior relation. Finally, self-control was associated with the improved translation of intentions into health behaviors and with greater inhibition of affective and habitual influences. Findings for the different pathways were not moderated by whether approach (health-protective behaviors) or avoidance responses (health-risk behaviors) were at issue. CONCLUSIONS: The present research offers new insights into why self-control promotes health behavior performance, and how deficits in self-control might be offset in future behavior-change interventions.

Self-control is the capacity to override impulses and is known to predict engagement in health behaviors. This article tests five hypotheses about how self-control drives health actions. We find that high self-control not only helps to override impulses (feelings and habits), it also influences (a) how favorable are people's thoughts, feelings, and intentions about health behaviors, (b) what considerations determine the intention to act (e.g., high self-control means people give higher priority to the perceived healthiness of the behavior and how much control they have over its performance), (c) whether people form habits that make it less effortful to perform health behaviors, and (d) how effectively people translate their "good" intentions into health behaviors. Thus, we find support for five different routes from self-control to engagement in health behaviors.

Reduction in Hospital Transfers at a US COVID-19 Alternate Care Site: Maintaining Surge Capacity Support in Imperial County, California.

OBJECTIVE: The transfer rate for patients from an Alternate Care Site (ACS) back to a hospital may serve as a metric of appropriate patient selection and the ability of an ACS to treat moderate to severely ill patients accepted from overwhelmed health-care systems. During the coronavirus infectious disease 2019 (COVID-19) pandemic, hospitals worldwide experienced acute surges of patients presenting with acute respiratory failure. METHODS: An ACS in Imperial County, California was re-established in November 2020 to help decompress 2 local hospitals experiencing surges of COVID-19 cases. The patients treated often had multiple comorbid illnesses and required a median supplemental oxygen of 3 L/min (LPM) on admission. Numerous interventions were initiated during a 2-wk period to improve clinical care delivery. RESULTS: The objectives of this retrospective observational study are to evaluate the impact of these clinical and staff interventions at an ACS on the transfer rate and to provide issues to consider for future ACS sites managing COVID-19 patients. CONCLUSIONS: The data suggest that continuous, real-time process-improvement interventions helped reduce the transfer rate back to hospitals from 36.7% to 14.5% and that an ACS is a viable option for managing symptomatic COVID-19 positive patients requiring hospital-level care when hospitals are overburdened.

Color scrambles reveal red and green half-wave linear mechanisms plus a mechanism selective for low chromatic contrast.

This paper introduces a new method to determine how subjects make discriminations among red-green texture stimuli. More specifically, the method determines (1) the number of mechanisms in human vision sensitive to lights that vary along the constant-S cardinal axis (cSCA) of DKL space and (2) the sensitivity of each mechanism to cSCA lights. Each of five subjects was tested in four, separately-blocked tasks. In each task, the subject strove to detect the location of a patch of cSCA-scramble (a spatially random mixture of cSCA lights) in a large, annular background of cSCA-scramble with a different histogram. In different tasks the target patch was (1) redder, (2) greener, (3) higher in red-green contrast, and (4) lower in red-green contrast than the background. For each subject in each task, we measure how target salience is influenced by different cSCA lights. By assuming that in each task each subject uses a weighted sum of his-or-her available mechanisms to construct a "tool" that is optimal for detecting the target, we can derive the sensitivity functions of the mechanisms underlying performance. Results suggest that human vision possesses three mechanisms sensitive to cSCA lights: a red half-wave linear mechanism, a complementary green half-wave linear mechanism, and a third mechanism that is activated by color-scrambles with low chromatic contrast in high-chromatic-contrast backgrounds.

Benchmarking the effectiveness of interventions to promote physical activity: A metasynthesis.

OBJECTIVE: The effectiveness of physical activity interventions is typically evaluated using null hypothesis significance testing or conventional interpretations of effect size (i.e., "small," "medium," or "large"). As these criteria have recently attracted criticism, we conducted a quantitative integration of meta-analyses (a metasynthesis) in order to provide precise, numerical estimates of intervention effectiveness. The research aimed to specify the percentile distribution of effect sizes in meta-analyses of physical activity trials, and their corresponding values for different types of activity (i.e., steps per day, minutes of moderate/vigorous physical activity [MVPA], meeting World Health Organization (WHO) physical activity guidelines). METHOD: Computerized searches identified 104 meta-analyses incorporating findings from 2,762 trials that met the inclusion criteria for the metasynthesis. RESULTS: The median effect size across all meta-analyses was d+ = .21, equivalent to an increase of 1,320 steps per day, 15.6 additional minutes of daily MVPA, and a 4.3% increase in the proportion of participants meeting WHO guidelines. Separate percentile distributions were computed for different samples (e.g., children, older adults, cancer survivors), measures of physical activity (i.e., objective vs. self-report), settings (e.g., schools, workplace), and follow-up periods (3+, 6+, and 12+ months). CONCLUSIONS: Conventional interpretations of effect size gravely misrepresent the effectiveness of interventions to promote physical activity. The percentile values for effect sizes, steps per days, minutes of MVPA, and percentage meeting guidelines reported here can be used to benchmark the effectiveness of future trials and should enable more informed judgments about trade-offs between effectiveness and considerations such as reach, burden, and cost. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Does increasing autonomous motivation or perceived competence lead to health behavior change? A meta-analysis.

OBJECTIVE: Despite abundant observational and experimental tests, it is not yet clear whether enhancing autonomous motivation or perceived competence leads to health behavior change. We identified interventions that aimed to change these constructs and quantified the magnitude of changes in behavior observed when interventions generated increases in autonomous motivation, perceived competence, or both. METHOD: Computerized searches and additional strategies identified 67 articles that yielded 135 effect sizes relevant to our research questions. Random effects meta-analyses were conducted via STATA. RESULTS: Interventions increased autonomous motivation and perceived competence in 31% and 38% of tests, respectively. Increasing autonomous motivation led to a medium change in health behaviors (d+ = .47, 95% CI [.44, .83]) and increasing perceived competence generated a small-to-medium change (d+ = .34, 95% CI [.22, .47]). Interventions that failed to generate significant improvements in autonomous motivation and perceived competence had much smaller effects on behavior change (d+ = .13 and .10, respectively). There was little evidence of synergistic effects. Changing both autonomous motivation and perceived competence (d+ = .42) did not lead to a larger effect on behavior compared with changing autonomous motivation on its own (d+ = .61), but had a larger effect compared with changing perceived competence on its own (d+ = .21). CONCLUSION: The present review suggests that autonomous motivation and perceived competence are valid targets for interventions to promote health behavior change but also indicates that research is warranted to ensure that interventions more effectively engage these targets. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Self-determination theory interventions for health behavior change: Meta-analysis and meta-analytic structural equation modeling of randomized controlled trials.

OBJECTIVE: We conducted a meta-analysis of randomized controlled trials (RCTs) to promote health behavior change based on self-determination theory (SDT). The review aimed to (a) quantify the impact of SDT interventions on health behaviors, (b) test mediation by theoretically specified variables (autonomous motivation and perceived competence), and (c) identify moderators of intervention effectiveness. METHOD: Computerized searches and additional strategies identified 56 articles that yielded 65 independent tests of SDT interventions. Random effects meta-analysis and metaregressions were conducted via STATA; meta-analytic structural equation modeling (MASEM) was used to test mediation. RESULTS: The sample-weighted average effect size for SDT interventions was d+ = .23, and there were significant effects for physical activity, sedentary behavior, diet, alcohol consumption, and smoking cessation (.16 ≥ d+ ≥ .29). Effect sizes exhibited both publication bias and small sample bias but remained significantly different from zero, albeit of smaller magnitude, after correction for bias (d+ ≥ .15). MASEM indicated that autonomous motivation and perceived competence mediated intervention effects on behavior. Metaregression analyses indicated that features of the sample, intervention, or methodology generally did not moderate effect sizes. CONCLUSION: The present review indicates that SDT interventions have a significant but small effect on health behavior change and suggests several directions for future research. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Reducing exposure to ultraviolet radiation from the sun and indoor tanning: A meta-analysis.

Objective: Skin cancer is the most frequently diagnosed cancer and rates are increasing because of global warming. This article reports a meta-analysis of randomized controlled trials of behavioral interventions to reduce exposure to ultraviolet radiation (UVR). The review aimed to (a) quantify the magnitude of intervention effects on indoor tanning, sun exposure, and sunscreen use, and (b) determine which intervention strategies maximize behavior change. Method: Out of 17,437 records identified via literature searches, 190 independent tests (N = 89,365) met the inclusion criteria. Sample, intervention, and methodological characteristics, and change techniques were coded, and random effects meta-analyses and metaregressions were conducted. Results: The sample-weighted average effect size across all studies was d+ = .193 (95% confidence interval, CI [.161, .226]), and there were significant effects on indoor tanning, sun exposure, and sunscreen use (d+ = .080, .149, and .196, respectively). However, there was evidence of publication bias, and trim and fill analyses indicated that the corrected effects for sun exposure and sunscreen use were of very small magnitude (d+ ~ .06) and were not significantly different from zero for indoor tanning (d+ = -.011, 95% CI [-.096, .074]). Metaregression analyses identified several intervention strategies that predicted effect sizes. For instance, interventions delivered individually that promoted alternatives to tanning were associated with larger effect sizes for indoor tanning. Conclusion: Interventions to date have had only a modest impact on behavioral exposure to UVR. The present findings offer new insights into how the effectiveness of future interventions can be improved. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Analysis of the visual spatiotemporal properties of American Sign Language.

Careful measurements of the temporal dynamics of speech have provided important insights into phonetic properties of spoken languages, which are important for understanding auditory perception. By contrast, analytic quantification of the visual properties of signed languages is still largely uncharted. Exposure to sign language is a unique experience that could shape and modify low-level visual processing for those who use it regularly (i.e., what we refer to as the Enhanced Exposure Hypothesis). The purpose of the current study was to characterize the visual spatiotemporal properties of American Sign Language (ASL) so that future studies can test the enhanced exposure hypothesis in signers, with the prediction that altered vision should be observed within, more so than outside, the range of properties found in ASL. Using an ultrasonic motion tracking system, we recorded the hand position in 3-dimensional space over time during sign language production of signs, sentences, and narratives. From these data, we calculated several metrics: hand position and eccentricity in space and hand motion speed. For individual signs, we also measured total distance travelled by the dominant hand and total duration of each sign. These metrics were found to fall within a selective range, suggesting that exposure to signs is a specific and unique visual experience, which might alter visual perceptual abilities in signers for visual information within the experienced range, even for non-language stimuli.

What works in smoking cessation interventions for cancer survivors? A meta-analysis.

OBJECTIVE: We conducted a meta-analysis of randomized controlled trials designed to promote smoking cessation among cancer survivors to (a) assess how effective interventions are at increasing quit rates, and (b) determine which intervention strategies are associated with effect sizes. METHODS: Out of 10,848 records that were located using computerized searches and informal sources, 21 interventions met the inclusion criteria for the review. We developed a bespoke taxonomy of 36 categories of techniques designed to change smoking behavior, and coded sample, intervention, and methodological characteristics. Random effects meta-analysis and metaregressions were conducted. RESULTS: The sample-weighted average effect size for smoking cessation was d+ = .030, and was not significantly different from zero (95%CI = -.042 to .101). Effect sizes exhibited both publication bias and small sample bias. Metaregressions indicated that, out of the many potential moderators that were tested, just a single intervention feature was associated with effect sizes. Interventions delivered solely by nurses exhibited larger effects compared to interventions from other sources. CONCLUSION: The present review indicates that current smoking cessation interventions for cancer survivors are ineffective. High-quality and effective interventions are needed. We offer suggestions regarding promising intervention strategies. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

A model of the uncertainty effects in choice reaction time that includes a major contribution from effector selection.

Hick's law describes the relation between choice reaction time (RT) and the number of stimulus-response alternatives (NA). For over half a century, this uncertainty effect has been ascribed primarily to the time taken to map a stimulus to its associated response. Here, data from 2 experiments suggests that selection of the appropriate effector-the particular body part to make a response-also contributes substantially to the uncertainty effect. This insight is important both for our understanding of basic cognitive architecture and because many classic experiments studying stimulus-response mapping have confounded NA with the number of effectors. Our data also suggest that, when stimuli are spatial and linked to the responses in an intuitively simple layout, the time required for stimulus-response mapping depends minimally on the NA, independent of effector. Experiment 1 demonstrated that in order to account for the complex patterns of uncertainty effects observed when stimulus type (spatial vs. symbolic), response mode (typing, with multiple effectors vs. touching with a single, known effector), and participant population (skilled vs. novice typists) are all manipulated a model is required that includes effector selection, along with stimulus-response mapping, and a proper treatment of stimulus-response repetitions. Using spatial indicator stimuli that minimized the contributions of stimulus-response mapping, Experiment 2 compared 4 effector conditions-the factorial combination of 1 or 3 fingers on one or both hands. The results showed that the increase in the uncertainty effect associated with the number of effectors is negatively accelerated and possibly additive across the variation of hands and fingers. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Promoting physical activity among cancer survivors: Meta-analysis and meta-CART analysis of randomized controlled trials.

OBJECTIVE: We conducted a meta-analysis of physical activity interventions among cancer survivors to (a) quantify the magnitude of intervention effects on physical activity and (b) determine what combination of intervention strategies maximizes behavior change. METHOD: Out of 32,626 records that were located using computerized searches, 138 independent tests (N = 13,050) met the inclusion criteria for the review. We developed a bespoke taxonomy of 34 categories of techniques designed to promote psychological change, and categorized sample, intervention, and methodological characteristics. Random effects meta-analysis and metaregressions were conducted; effect size data were also submitted to meta-analysis with classification and regression trees (i.e., meta-CART). RESULTS: The sample-weighted average effect size for physical activity interventions was d+ = .35, equivalent to an increase of 1,149 steps per day. Effect sizes exhibited both publication bias and small sample bias but remained significantly different from zero, albeit of smaller magnitude (d+ ≥ .20), after correction for bias. Meta-CART indicated that the major difference in effectiveness was attributable to supervised versus unsupervised programs (d+ = .49 vs. .26). Greater contact time was associated with larger effects in supervised programs. For unsupervised programs, establishing outcome expectations, greater contact time, and targeting overweight or sedentary participants each predicted greater program effectiveness, whereas prompting barrier identification and providing workbooks were associated with smaller effect sizes. CONCLUSION: The present review indicates that interventions have a small but significant effect on physical activity among cancer survivors and offers insights into how the effectiveness of future interventions might be improved. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Variation in target and distractor heterogeneity impacts performance in the centroid task.

In a selective centroid task, the participant views a brief cloud of items of different types-some of which are targets, the others distractors-and strives to mouse-click the centroid of the target items, ignoring the distractors. Advantages of the centroid task are that multiple target types can appear in the same display and that influence functions, which estimate the weight of each stimulus type in the cloud on the perceived centroid for each participant, can be obtained easily and efficiently. Here we document the strong, negative impact on performance that results when the participant is instructed to attend to target dots that consist of two or more levels of a single feature dimension, even when those levels differ categorically from those of the distractor dots. The results also show a smaller, but still observable decrement in performance that results when there is heterogeneity in the distractor dots.

How can observers use perceived size? Centroid versus mean-size judgments.

statistical representations are aggregate properties of the environment that are presumed to be perceived automatically and preattentively. We investigated two tasks presumed to involve these representations: judgments of the centroid of a set of spatially arrayed items and judgments of the mean size of the items in the array. The question we ask is: When similar information is required for both tasks, do observers use it with equal postfilter efficiency (Sun, Chubb, Wright, & Sperling, 2016)? We find that, according to instructions, observers can either efficiently utilize item size in making centroid judgments or ignore it almost completely. Compared to centroid judgments, however, observers estimating mean size incorporate the size of individual items into the average with low efficiency.

High-capacity preconscious processing in concurrent groupings of colored dots.

Grouping is a perceptual process in which a subset of stimulus components (a group) is selected for a subsequent-typically implicit-perceptual computation. Grouping is a critical precursor to segmenting objects from the background and ultimately to object recognition. Here, we study grouping by color. We present subjects with 300-ms exposures of 12 dots colored with the same but unknown identical color interspersed among 14 dots of seven different colors. To indicate grouping, subjects point-click the remembered centroid ("center of gravity") of the set of homogeneous dots, of heterogeneous dots, or of all dots. Subjects accurately judge all of these centroids. Furthermore, after a single stimulus exposure, subjects can judge both the heterogeneous and homogeneous centroids, that is, subjects simultaneously group by similarity and by dissimilarity. The centroid paradigm reveals the relative weight of each dot among targets and distractors to the underlying grouping process, offering a more detailed, quantitative description of grouping than was previously possible. A change detection experiment reveals that conscious memory contains less than two dots and their locations, whereas an ideal detector would have to perfectly process at least 15 of 26 dots to match the subjects' centroid judgments-indicating an extraordinary capacity for preconscious grouping. A different color set yielded identical results. Grouping theories that rely on predefined feature maps would fail to explain these results. Rather, the results indicate that preconscious grouping is automatic, flexible, and rapid, and a far more complex process than previously believed.

Human attention filters for single colors.

The visual images in the eyes contain much more information than the brain can process. An important selection mechanism is feature-based attention (FBA). FBA is best described by attention filters that specify precisely the extent to which items containing attended features are selectively processed and the extent to which items that do not contain the attended features are attenuated. The centroid-judgment paradigm enables quick, precise measurements of such human perceptual attention filters, analogous to transmission measurements of photographic color filters. Subjects use a mouse to locate the centroid-the center of gravity-of a briefly displayed cloud of dots and receive precise feedback. A subset of dots is distinguished by some characteristic, such as a different color, and subjects judge the centroid of only the distinguished subset (e.g., dots of a particular color). The analysis efficiently determines the precise weight in the judged centroid of dots of every color in the display (i.e., the attention filter for the particular attended color in that context). We report 32 attention filters for single colors. Attention filters that discriminate one saturated hue from among seven other equiluminant distractor hues are extraordinarily selective, achieving attended/unattended weight ratios >20:1. Attention filters for selecting a color that differs in saturation or lightness from distractors are much less selective than attention filters for hue (given equal discriminability of the colors), and their filter selectivities are proportional to the discriminability distance of neighboring colors, whereas in the same range hue attention-filter selectivity is virtually independent of discriminabilty.

Evidence against global attention filters selective for absolute bar-orientation in human vision.

The finding that an item of type A pops out from an array of distractors of type B typically is taken to support the inference that human vision contains a neural mechanism that is activated by items of type A but not by items of type B. Such a mechanism might be expected to yield a neural image in which items of type A produce high activation and items of type B low (or zero) activation. Access to such a neural image might further be expected to enable accurate estimation of the centroid of an ensemble of items of type A intermixed with to-be-ignored items of type B. Here, it is shown that as the number of items in stimulus displays is increased, performance in estimating the centroids of horizontal (vertical) items amid vertical (horizontal) distractors degrades much more quickly and dramatically than does performance in estimating the centroids of white (black) items among black (white) distractors. Together with previous findings, these results suggest that, although human vision does possess bottom-up neural mechanisms sensitive to abrupt local changes in bar-orientation, and although human vision does possess and utilize top-down global attention filters capable of selecting multiple items of one brightness or of one color from among others, it cannot use a top-down global attention filter capable of selecting multiple bars of a given absolute orientation and filtering bars of the opposite orientation in a centroid task.

The centroid paradigm: Quantifying feature-based attention in terms of attention filters.

This paper elaborates a recent conceptualization of feature-based attention in terms of attention filters (Drew et al., Journal of Vision, 10(10:20), 1-16, 2010) into a general purpose centroid-estimation paradigm for studying feature-based attention. An attention filter is a brain process, initiated by a participant in the context of a task requiring feature-based attention, which operates broadly across space to modulate the relative effectiveness with which different features in the retinal input influence performance. This paper describes an empirical method for quantitatively measuring attention filters. The method uses a "statistical summary representation" (SSR) task in which the participant strives to mouse-click the centroid of a briefly flashed cloud composed of items of different types (e.g., dots of different luminances or sizes), weighting some types of items more strongly than others. In different attention conditions, the target weights for different item types in the centroid task are varied. The actual weights exerted on the participant's responses by different item types in any given attention condition are derived by simple linear regression. Because, on each trial, the centroid paradigm obtains information about the relative effectiveness of all the features in the display, both target and distractor features, and because the participant's response is a continuous variable in each of two dimensions (versus a simple binary choice as in most previous paradigms), it is remarkably powerful. The number of trials required to estimate an attention filter is an order of magnitude fewer than the number required to investigate much simpler concepts in typical psychophysical attention paradigms.

Bimodal distribution of performance in discriminating major/minor modes.

This study investigated the abilities of listeners to classify various sorts of musical stimuli as major vs minor. All stimuli combined four pure tones: low and high tonics (G5 and G6), dominant (D), and either a major third (B) or a minor third (B[symbol: see text]). Especially interesting results were obtained using tone-scrambles, randomly ordered sequences of pure tones presented at ≈15 per second. All tone-scrambles tested comprised 16 G's (G5's + G6's), 8 D's, and either 8 B's or 8 B[symbol: see text]'s. The distribution of proportion correct across 275 listeners tested over the course of three experiments was strikingly bimodal, with one mode very close to chance performance, and the other very close to perfect performance. Testing with tone-scrambles thus sorts listeners fairly cleanly into two subpopulations. Listeners in subpopulation 1 are sufficiently sensitive to major vs minor to classify tone-scrambles nearly perfectly; listeners in subpopulation 2 (comprising roughly 70% of the population) have very little sensitivity to major vs minor. Skill in classifying major vs minor tone-scrambles shows a modest correlation of around 0.5 with years of musical training.