Smoking behavior among low-income black adults: patterns and correlates of smoking trajectories

INTRODUCTION

Limited research has focused on identifying smoking patterns and correlates of cigarette use among low-income Blacks. Identifying smoking patterns and correlates of use would assist health providers to develop more culturally sensitive interventions.

METHODS

A semiparametric group-based trajectory modeling strategy was used to empirically identify patterns of cigarette use among 947 low-income Black adults (47% women) enrolled in a sexual risk reduction intervention at a sexually transmitted disease clinic. Patients' cigarette use was assessed 4 times over a 12-month period; correlates of cigarette use were examined.

RESULTS

Six smoking trajectories were empirically identified: none/rare smokers (n = 536), decreasing light smokers (n = 69), increasing light smokers (n = 51), low light smokers (n = 112), upper light smokers (n = 142), and moderate smokers (n = 33). Smoking trajectories were predicted by alcohol use, prior substance use treatment, marijuana use, and other illegal drug use, but the patterns varied by trajectory.

DISCUSSION

Results from this study show that Blacks' smoking patterns are associated with several risk factors. These findings suggest that development of prevention and cessation programs should be targeted to the specific needs of Blacks' smoking trajectories.

Patients with chronic hepatitis C undergoing watchful waiting: Exploring trajectories of illness uncertainty and fatigue

We identified trajectories of illness uncertainty in chronic hepatitis C patients and examined their association with fatigue levels during 12 months of disease monitoring without treatment (watchful waiting). Sixty-two men and 63 women completed uncertainty and fatigue measures. Groups were formed by uncertainty scores (high, medium, and low) at baseline. Baseline fatigue levels were higher in the high uncertainty group than in the medium and low groups. Over time, uncertainty levels did not change. Fatigue levels in the low uncertainty group remained constant, increased in the medium, and decreased in the high groups. Findings suggest that uncertainty and fatigue do not remit spontaneously. Being aware of this may help nurses identify those patients needing support for these two concerns.

Concept mapping of diet and physical activity: uncovering local stakeholders perception in the Quebec City region

Overweight and obesity are major public health concerns that are neither evenly distributed among the population nor between regions. Many studies suggest that beyond individual characteristics, the place where one lives influences lifestyle choices that underpin overweight and obesity. We observed such a situation in the province of Quebec (Canada), and because data availability from surveys was limited to a local level, the observed overweight disparities between local communities could not be entirely explained. Aiming to uncover local factors not captured by national survey data sets and in order to aid local level intervention, we investigated how the overweight problem was perceived by stakeholders through a concept mapping methodology. Concept mapping is a mixed method that relies upon stakeholders' perception as well as statistical techniques to draw a synthesis of the problem in the form of a conceptual map. A total of 45 stakeholders working in four areas with contrasting overweight prevalence in the Quebec City region were involved in the process. The map enables a global understanding of stakeholders' perception. This perception is not necessarily in line with public health knowledge however. For example, key concepts on the map suggest that physical activity is perceived to be much more important than diet with regards to population overweight and that urban design elements seem to be of low concern. Concept mapping is an innovative tool for planning and evaluation and can help stakeholders to develop adapted interventions to promote healthy lifestyle. It also provides relevant information to enhance the comprehension of local health disparities with a geographical perspective where data availability is limited.

Left-right coding of past and future in language: the mental timeline during sentence processing

The metaphoric mapping theory suggests that abstract concepts, like time, are represented in terms of concrete dimensions such as space. This theory receives support from several lines of research ranging from psychophysics to linguistics and cultural studies; especially strong support comes from recent response time studies. These studies have reported congruency effects between the dimensions of time and space indicating that time evokes spatial representations that may facilitate or impede responses to words with a temporal connotation. The present paper reports the results of three linguistic experiments that examined this congruency effect when participants processed past- and future-related sentences. Response time was shorter when past-related sentences required a left-hand response and future-related sentences a right-hand response than when this mapping of time onto response hand was reversed (Experiment 1). This result suggests that participants can form time-space associations during the processing of sentences and thus this result is consistent with the view that time is mentally represented from left to right. The activation of these time-space associations, however, appears to be non-automatic as shown by the results of Experiments 2 and 3 when participants were asked to perform a non-temporal meaning discrimination task.

Circadian rhythm in force tracking and in dual task costs

The present study determined a circadian rhythm in force control during a visually guided tracking task under single task conditions (i.e., tracking task presented alone) and dual task conditions (i.e., tracking task together with a memory task). Nine healthy young male subjects participated in a Constant Routine protocol involving a week of regular bedtimes, a baseline night of 8 h sleep, and subsequent wakefulness of 40 h. Subjects performed an eye-hand coordination task that required tracking an unpredictable target (presented on a computer screen) by using grip force to adjust a visual feedback to the changing target. Tracking performance (both in precision and delay) were time-of-day-specific with worst performance at around 04:00 h. The dual task costs, as an index of interference of two tasks performed simultaneously, only showed a significant effect of the memory task on tracking precision during the circadian minimum. In contrast, dual task costs were close to zero during midday and absent in tracking delay. Tracking precision descriptively revealed inter-individual differences: half of the subjects maintained fairly stable performance during the 40 h of wakefulness, whereas the other half showed a clear circadian rhythmicity in tracking precision. Thus, tracking precision seems to be a sensitive parameter for conditions of divided attention and inter-individual variability during the circadian minimum, whereas tracking delay revealed neither a dichotomy of task conditions nor inter-individual differences in performance-amplitude over sessions. Nonetheless, both tracking precision and delay showed a comparable circadian rhythmicity.

Body mass trajectories through adulthood: results from the National Longitudinal Survey of Youth 1979 Cohort (1981-2006)

BACKGROUND

Most studies describing change in body mass through adulthood model an 'average' trajectory bearing the same functional form in the underlying population. Latent-class growth modelling has revealed the presence of several underlying body mass/obesity trajectory groups among children and adolescents, but has not been applied to capture adult body mass trajectories. We apply the technique to identify adult body mass trajectory groups, risk factors for group membership and (time-varying) modifiers of trajectory level within each group, and assess association between group membership and important health outcomes in midlife.

METHODS

Body mass trajectory groups, from age 18 to 49 years, were identified using latent-class growth modelling based on the National Longitudinal Survey of Youth 1979 (n = 9681). Role of gender, race/ethnicity and age cohort as risk factors for group membership, and of highest grade of education completed, years of urban living, years in employment, years in poverty and years married as modifiers of trajectory level was evaluated.

RESULTS

Four trajectory groups, 'normal weight', 'overweight', 'late adulthood obesity' and 'early adulthood obesity' were identified. Males, Blacks and those born later had higher odds of being in the three latter groups. More education and years married lowered the trajectory within each group. The prevalence of most health outcomes was lowest in the 'normal weight' group, somewhat greater in the 'overweight' group, greater again in the 'late adult obesity group' and highest in the 'early adulthood obesity' group.

CONCLUSION

Regular body mass index screening and monitoring in early adult life may identify a person as belonging to one of these four groups early, and allow the individual and health-care providers opportunities to initiate behavioural or other interventions better tailored to the specific group.

Unattended musical beats enhance visual processing

The present study investigated whether and how a musical rhythm entrains a listener's visual attention. To this end, participants were presented with pictures of faces and houses and indicated whether picture orientation was upright or inverted. Participants performed this task in silence or with a musical rhythm playing in the background. In the latter condition, pictures could occur off-beat or on a rhythmically implied, silent beat. Pictures presented without the musical rhythm and off-beat were responded to more slowly than pictures presented on-beat. This effect was comparable for faces and houses. Together these results indicate that musical rhythm both synchronizes and facilitates concurrent stimulus processing.

A bilateral advantage for storage in visual working memory

Various studies have demonstrated enhanced visual processing when information is presented across both visual hemifields rather than in a single hemifield (the bilateral advantage). For example, Alvarez and Cavanagh (2005) reported that observers were able to track twice as many moving visual stimuli when the tracked items were presented bilaterally rather than unilaterally, suggesting that independent resources enable tracking in the two visual fields. Motivated by similarities in the apparent capacity and neural substrates that mediate tracking and visual working memory (WM), the present work examined whether or not a bilateral advantage also arises during storage in visual WM. Using a recall procedure to assess working memory for orientation information, we found a reliable bilateral advantage; recall error was smaller with bilateral sample displays than with unilateral displays. To demonstrate that the bilateral advantage influenced storage per se rather than just encoding efficiency, we replicated the observed bilateral advantage using sequentially presented stimuli. Finally, to further characterize how bilateral presentations enhanced storage in working memory, we measured both the number and the resolution of the stored items and found that bilateral presentations lead to an increased probability of storage, rather than enhanced mnemonic resolution. Thus, the bilateral advantage extends beyond the initial selection and encoding of visual information to influence online maintenance in visual working memory.

Can human movement analysis contribute to usability understanding?

Nowadays human-machine interfaces are evaluated using different methodologies. These methodologies rarely consider the human movements involved in the interaction, and if so, the movements are considered in a simplistic manner. Another often neglected aspect is the relationship between the learning process and the use of the interface. Traditional approaches of cognitive modeling consider learning as just one continuous process. However there is some current evidence of concurrent processes on different time scales. This paper aims to answer, with experimental measurements, if learning actually implies a set of concurrent processes, if those processes are related to the coordinative aspects of hand movement, and how this can vary between young adult and elderly users. Two different interfaces, a washing machine and a domotic system, were analyzed with 23 and 20 people, respectively, classified as men or women and elderly (over 55) or adult (between 40 and 50). The results of the study provide support for the existence of different concurrent processes in learning, previously demonstrated for motor tasks. Moreover, the learning process is actually associated with changes in movement patterns. Finally, the results show that the progression of the learning process depends on age, although elderly people are equally capable of learning to use technological systems as young adults.

Errors of somatosensory localisation in a patient with right-hemisphere stroke

Following a right-hemisphere stroke, Patient NG could detect somatosensory stimulation that she was unable to localise. With vision precluded, NG systematically mislocalized touch on the little and ring finger of her affected left hand, and reported feeling this touch on the neighbouring rightward finger. This pattern of mislocalization occurred not only when the Examiner administered touch but also when touch was self-administered. We manipulated the relative position of NG's two hands during sensory assessment of the affected hand. When NG's right hand was positioned to the left of her affected hand, NG exhibited improved localisation. Theoretical and clinical implications are discussed.

A role for the insula in color-induced nasal thermal sensations

This article is the first step towards understanding the mechanisms underlying the intriguing, recently discovered lateralized color-induced nasal thermal sensations. In the presence of color cues and complete absence of thermal stimulus, larger sensitivity of the left nostril/right hemisphere (RH) for warming sensations and larger right nostril/left hemisphere (LH) for cooling sensations were replicated several times. It was suggested that engagement in a temperature judgment task and the development of specific expectancies due to the presence of color cues could alter and enhance processing in brain areas involved in thermosensory processing, such as the middle/posterior insula. The lateralized patterns could thus intimate hemispheric specialization for thermosensory processing. However, such lateralization may be due to either exclusive specialization of each hemisphere or specialization-through-reciprocal inhibition between the hemispheres. The two hypotheses predict different results following a unilateral insular stroke. Here, we present the results of a sample of healthy volunteers and patient MB, a young woman suffering from unilateral left-side damage of the posterior insula, in a task involving color-induced nasal thermal judgment. The expected lateralized pattern was found in the performance of the controls. In line with our previous suggestions that the LH is more involved in the processing of cooling sensations, patient MB exhibited changes only in the judgment of cooling sensations. Her results also clearly support the specialization-through-reciprocal inhibition account since she exhibited decreased cooling judgments contralaterally but increased cooling judgments ipsilaterally. Accordingly, we conclude that (a) the lateralized patterns arise because of hemispheric specialization; (b) the LH is seemingly more involved in the processing of cooling sensations; (c) this specialization is underlain by reciprocal interhemispheric inhibition; and (d) even in the absence of thermal stimulus, the development of expectancies suffices to activate modality-specific brain areas involved in the current task in such a way that damage to these areas disturbs the corresponding specific processes.

Probing the face-space of individuals with prosopagnosia

A useful framework for understanding the mental representation of facial identity is face-space (Valentine, 1991), a multi-dimensional cognitive map in which individual faces are coded relative to the average of previously encountered faces, and in which the distance among faces represents their perceived similarity. We examined whether individuals with prosopagnosia, a disorder characterized by an inability to recognize familiar faces despite normal visual acuity and intellectual abilities, evince behavior consistent with this underlying representational schema. To do so, we compared the performance of 6 individuals with congenital prosopagnosia (CP), with a group of age- and gender-matched control participants in a series of experiments involving judgments of facial identity. We used digital images of male and female faces and morphed them to varying degrees relative to an average face, to create caricatures, anti-caricatures, and anti-faces (i.e. faces of the opposite identity). Across 5 behavioral tasks, CP individuals' performance was similar to that of the control group and consistent with the face-space framework. As a test of the sensitivity of our measures in revealing face processing abnormalities, we also tested a single acquired prosopagnosic (AP) individual, whose performance on the same tasks deviated significantly from the control and CP groups. The findings suggest that, despite an inability to recognize individual identities, CPs perceive faces in a manner consistent with norm-based coding of facial identity, although their representation is likely supported by a feature-based strategy. We suggest that the apparently normal posterior cortical regions, including the fusiform face area, serve as the neural substrate for at least a coarse, feature-based face-space map in CP and that their face recognition impairment arises from the disconnection between these regions and more anterior cortical sites.

Differential effects of prolonged work on performance measures in self-paced speed tests

Time-related changes in the speeded performance of complex cognitive tasks are considered to arise from the combined effects of practice and mental fatigue. Here we explored the differential contributions of practice and fatigue to performance changes in a self-paced speeded mental addition and comparison task of about 50 min duration, administered twice within one week’s time. Performance measures included average response speed, accuracy, and response speed variability. The results revealed differential effects of prolonged work on different performance indices: Practice effects, being more pronounced in the first session, were reflected in an improvement of average response speed, whereas mental fatigue, occurring in both sessions, was reflected in an increase of response speed variability. This demonstrates that effects of mental fatigue on average speed of performance may be masked by practice effects but still be detectable in the variability of performance. Therefore, besides experimental factors such as the length and complexity of tasks, indices of response speed variability should be taken into consideration when interpreting different aspects of performance in self-paced speed tests.

Energetic effects of stimulus intensity on prolonged simple reaction-time performance

The efficiency of cognition is modulated by energetic factors like effort, fatigue or circadian variation, which affect even the most basic cognitive operations. For instance, speeded detection in simple reaction-time (SRT) tasks usually slows down over time. The literature suggests that either mindlessness due to routinization or mental fatigue due to attentional resource depletion might underlie this decrement. We tested these assumptions in three 25-min visual SRT tasks using easy-to-detect high-intensity and hard-to-detect low-intensity stimuli presented in both blocked and mixed fashion. Mindlessness theory predicts that less monotonous stimulation (i.e. the mixed presentation) would mitigate the time-related decrement for high- and low-intensity stimuli alike, whereas resource-depletion theory predicts opposite effects of mixed presentation on high- versus low-intensity stimuli. Indeed, stimulus intensity and presentation mode cross-interacted significantly, indicating that the performance decline was steeper for high-intensity stimuli but less steep for low-intensity stimuli during mixed compared to blocked presentation, respectively. These results strongly suggest that the time-related efficiency decrement during prolonged SRT performance is related to accumulating mental fatigue. A conjecture is put forward that explains both resource depletion and mindlessness from the perspective of self-regulation. Our study underscores the need to incorporate energetic factors into models of cognition to facilitate their translation into real-world applications.

The effect of perceived motion-in-depth on time perception

The present study examined the effect of perceived motion-in-depth on temporal interval perception. We required subjects to estimate the length of a short empty interval starting from the offset of a first marker and ending with the onset of a second marker. The size of the markers was manipulated so that the subjects perceived a visual object as approaching or receding. We demonstrated that the empty intervals between markers was perceived as taking shorter to view when the object was perceived as approaching than when it was perceived as receding. We found in addition that the motion-in-depth effect disappeared when the shape continuity between the first and second marker was broken or when the object approached but missed the face. We conclude that anticipated collision of an approaching object altered perception of an empty interval.

Neural correlates of sequence encoding in visuomotor learning

To examine the neural basis of sequence learning, a fundamental but poorly understood human ability, we recorded event-related potentials (ERPs) while subjects viewed and memorized randomly directed sequences of motions for later imitation. Previously, we found that the amplitude of ERPs elicited by successive motion segments decreased as a function of each segment's serial position. This happened when subjects were required to remember the sequence, but not when they were performing a perceptual task. Here, to study the functional significance of this amplitude gradient in sequence learning, we presented each sequence several times in succession and examined changes in ERP amplitude as subjects learned the sequence through repeated observation and imitation. Behaviorally, with each repetition subjects grew more accurate in reproducing what they had seen. At the same time, ERPs grew smaller with each successive presentation, replicating and extending previous demonstrations of repetition suppression. Importantly, a comparison of ERPs to segments occupying different serial positions within a sequence revealed a decreasing amplitude gradient that grew steeper with sequence repetition. This sharpening of the amplitude gradient may reflect an explicit encoding process that relies on a magnitude code for serial order.

Mental fatigue and temporal preparation in simple reaction-time performance

Performance decrements attributed to mental fatigue have been found to be especially pronounced in tasks that involve the voluntary control of attention. Here we explored whether mental fatigue from prolonged time on task (TOT) also impairs temporal preparation for speeded action in a simple reaction-time task. Temporal preparation is enabled by a warning signal presented before the imperative stimulus and usually results in shorter reaction time (RT). When the delay between warning and imperative stimuli - the foreperiod (FP) - varies between trials, responses are faster with longer FPs. This pattern has been proposed to arise from either voluntary attentional processes (temporal orienting) or automatic trial-to-trial learning (trace conditioning). The former account suggests a selective RT increase on long-FP trials with fatigue; the latter account suggests no such change. Over a work period of 51 min, we found the typical increase in overall RT but no selective RT increase after long FPs. This additivity indicates that TOT-induced mental fatigue generally reduces cognitive efficiency but leaves temporal preparation under time uncertainty unaffected. We consider this result more consistent with the trace-conditioning account of temporal preparation.

Attentional control settings prevent abrupt onsets from capturing visual spatial attention

When a visual distractor appears earlier than a visual target in a target-detection task, response time is faster if the distractor appears at the same location as the target. When a visual distractor appears concurrently with a visual target in a target-detection task, response time is slowed relative to when no distractor is presented. Both effects have been taken as evidence of the capture of visual spatial attention, yet capture by early distractors is contingent on top-down attentional control settings (ACSs), and capture by concurrent distractors is not. The present study evaluated whether this incongruity is attributable to the timing of distractors (earlier than vs. concurrently with the target), or to the employed comparisons (same location/different location vs. distractor/no distractor). Using a task that presented both early and concurrent distractors, we observed that, regardless of timing, capture was contingent on ACSs when assessed by the same-location/different-location comparison. This result suggests that, although irrelevant stimuli cause nonspatial purely stimulus-driven effects, the capture of visual spatial attention is contingent on ACSs.

[Determinants of geographic variations in asthma medication in Quebec]

BACKGROUND

The study of geographic variations in the use of medication can constitute an interesting and useful option in public health surveillance for the identification of population needs and for the fair partition of resources. Many studies report variations in the use of medication that are not always understood. Considering the importance of medication, particularly for chronic diseases like asthma, it is important to identify factors that can explain geographic differences in the utilization of medications in order to determine optimal prescription practices.

METHODS

We used a multilevel analysis to explore determinants of variation among welfare recipients and subscribers covered by the Quebec public drug plan, aged five to 44, who claimed at least one prescription for an asthmatic medication in 2003. The analysis was based on 73 small areas in Quebec's 15 health regions.

RESULTS

Prevalence of usage and hospitalization rates are the main predictors of variation in medication intensity. On the other hand, prevalence of usage is related to the area of residence, proportion of welfare recipients and prevalence of smokers. The quality of medication is related to practitioners' specialty.

CONCLUSION

Different factors contribute to the understanding of geographic variations in asthma medication but it remains important to control for severity. Small area analysis makes it possible to identify specific areas facing more important problems in the prevalence and use of medication for asthma and thus leads to better understanding of local needs for more targeted interventions.

Classical item and test analysis with graphics: the ViSta-CITA program

Current advances in test development theory have mostly been influenced by item response theory. Notwithstanding this, classical test theory still plays a major part in the development of tests for applied educational and behavioral research. This article describes ViSta-CITA, a computer program that implements a set of classical item and test analysis methods that incorporate innovative graphics whose aim is to provide deeper insight into analysis results. Such an aim is achieved through the SpreadPlot, a graphical method designed to display multiple, simultaneous, interactive views of the analysis results. It behaves on a dynamic basis, so that users' changes (e.g., selecting a subset of items) are automatically updated in the graphical windows showing the analysis results. Moreover, ViSta-CITA is freely available, and its code is open to modifications or additions by the user. Features such as these constitute useful tools for research and teaching purposes related to test development.

Dissociations and interactions between time, numerosity and space processing

This study investigated time, numerosity and space processing in a patient (CB) with a right hemisphere lesion. We tested whether these magnitude dimensions share a common magnitude system or whether they are processed by dimension-specific magnitude systems. Five experimental tasks were used: Tasks 1-3 assessed time and numerosity independently and time and numerosity jointly. Tasks 4 and 5 investigated space processing independently and space and numbers jointly. Patient CB was impaired at estimating time and at discriminating between temporal intervals, his errors being underestimations. In contrast, his ability to process numbers and space was normal. A unidirectional interaction between numbers and time was found in both the patient and the control subjects. Strikingly, small numbers were perceived as lasting shorter and large numbers as lasting longer. In contrast, number processing was not affected by time, i.e. short durations did not result in perceiving fewer numbers and long durations in perceiving more numbers. Numbers and space also interacted, with small numbers answered faster when presented on the left side of space, and the reverse for large numbers. Our results demonstrate that time processing can be selectively impaired. This suggests that mechanisms specific for time processing may be partially independent from those involved in processing numbers and space. However, the interaction between numbers and time and between numbers and space also suggests that although independent, there maybe some overlap between time, numbers and space. These data suggest a partly shared mechanism between time, numbers and space which may be involved in magnitude processing or may be recruited to perform cognitive operations on magnitude dimensions.

The role of the parietal lobe in visual extinction studied with transcranial magnetic stimulation

Interhemispheric competition between homologous areas in the human brain is believed to be involved in a wide variety of human behaviors from motor activity to visual perception and particularly attention. For example, patients with lesions in the posterior parietal cortex are unable to selectively track objects in the contralesional side of visual space when targets are simultaneously present in the ipsilesional visual field, a form of visual extinction. Visual extinction may arise due to an imbalance in the normal interhemispheric competition. To directly assess the issue of reciprocal inhibition, we used fMRI to localize those brain regions active during attention-based visual tracking and then applied low-frequency repetitive transcranial magnetic stimulation over identified areas in the left and right intraparietal sulcus to asses the behavioral effects on visual tracking. We induced a severe impairment in visual tracking that was selective for conditions of simultaneous tracking in both visual fields. Our data show that the parietal lobe is essential for visual tracking and that the two hemispheres compete for attentional resources during tracking. Our results provide a neuronal basis for visual extinction in patients with parietal lobe damage.

Circadian rhythm in handwriting

The aim of the present study was to determine whether the motor process of handwriting is influenced by a circadian rhythm. Nine healthy young male subjects underwent a 40-h sleep deprivation protocol under constant routine conditions. Starting at 09:00 hours, subjects performed every 3 h two handwriting tasks of different complexity. Handwriting performance was evaluated by writing speed, writing fluency and script size. The frequency of handwriting, as a measure of movement speed, revealed a circadian rhythm, validated by harmonic regression, with a slowing at the time of the onset of melatonin secretion (22:17 hours) and a trough in the very early morning at around 03:30 hours. In the temporal variability of handwriting an effect of task complexity was suggested in the direction of circadian variations in parallel with speed only for the sentence. Despite deficits of speed and temporal variability, writing fluency did not change significantly across sessions indicating that the basic automation of handwriting was preserved at any time. On the second day, daytime levels of the kinematics of handwriting did not reflect impaired performance after sleep deprivation. Our results show for the first time a clear circadian rhythm for the production of handwriting.

Effects of neighbourhood-level educational attainment on HIV prevalence among young women in Zambia

BACKGROUND

Investigations of the association between socio-economic position indicators and HIV in East, Central and Southern Africa have chiefly focused on factors that pertain to individual-level characteristics. This study investigated the effect of neighbourhood educational attainment on HIV prevalence among young women in selected urban and rural areas in Zambia.

METHODS

This study re-analysed data from a cross-sectional population survey conducted in Zambia in 2003. The analyses were restricted to women aged 15-24 years (n = 1295). Stratified random cluster sampling was used to select 10 urban and 10 rural clusters. A measure for neighbourhood-level educational attainment was constructed by aggregating individual-level years-in-school. Multi-level mixed effects regression models were run to examine the neighbourhood-level educational effect on HIV prevalence after adjusting for individual-level underlying variables (education, currently a student, marital status) and selected proximate determinants (ever given birth, sexual activity, lifetime sexual partners).

RESULTS

HIV prevalence among young women aged 15-24 years was 12.5% in the urban and 6.8% in the rural clusters. Neighbourhood educational attainment was found to be a strong determinant of HIV infection in both urban and rural population, i.e. HIV prevalence decreased substantially by increasing level of neighbourhood education. The likelihood of infection in low vs. high educational attainment of neighbourhoods was 3.4 times among rural women and 1.8 times higher among the urban women after adjusting for age and other individual-level underlying variables, including education. However, the association was not significant for urban young women after this adjustment. After adjusting for level of education in the neighbourhood, the effect of the individual-level education differed by residence, i.e. a strong protective effect among urban women whereas tending to be a risk factor among rural women.

CONCLUSION

The findings suggested structural effects on HIV prevalence. Future research should include more detailed mapping of neighbourhood factors of relevance to HIV transmission as part of the effort to better understand the causal mechanisms involved.

Adaptation and learning: characteristic time scales of performance dynamics

A multiple time scales landscape model is presented that reveals structures of performance dynamics that were not resolved in the traditional power law analysis of motor learning. It shows the co-existence of separate processes during and between practice sessions that evolve in two independent dimensions characterized by time scales that differ by about an order of magnitude. Performance along the slow persistent dimension of learning improves often as much and sometimes more during rest (memory consolidation and/or insight generation processes) than during a practice session itself. In contrast, the process characterized by the fast, transient dimension of adaptation reverses direction between practice sessions, thereby significantly degrading performance at the beginning of the next practice session (warm-up decrement). The theoretical model fits qualitatively and quantitatively the data from Snoddy's [Snoddy, G. S. (1926). Learning and stability. Journal of Applied Psychology, 10, 1-36] classic learning study of mirror tracing and other averaged and individual data sets, and provides a new account of the processes of change in adaptation and learning.

Selective Visual Attention and Motivation

Learning to associate the probability and value of behavioral outcomes with specific stimuli (value learning) is essential for rational decision making. However, in demanding cognitive conditions, access to learned values might be constrained by limited attentional capacity. We measured recognition of briefly presented faces seen previously in a value-learning task involving monetary wins and losses; the recognition task was performed both with and without constraints on available attention. Regardless of available attention, recognition was substantially enhanced for motivationally salient stimuli (i.e., stimuli highly predictive of outcomes), compared with equally familiar stimuli that had weak or no motivational salience, and this effect was found regardless of valence (win or loss). However, when attention was constrained (because stimuli were presented during an attentional blink, AB), valence determined recognition; win-associated faces showed no AB, but all other faces showed large ABs. Motivational salience acts independently of attention to modulate simple perceptual decisions, but when attention is limited, visual processing is biased in favor of reward-associated stimuli.

Contextual effects on number-time interaction

Time perception has long been known to be affected by numerical representations. Recent studies further demonstrate that when participants estimate the duration of Arabic numbers, number magnitude, though task-irrelevant, biases duration judgment to produce underestimation for smaller numbers and overestimation for larger numbers. Such effects were found in the present study to be significantly reduced when a weight unit gram was suffixed to the numbers rendering the mental magnitude differences between different numbers less distinctive. The effects were enhanced when a different unit kilogram was suffixed to the numbers enlarging the perceived magnitude differences between different numbers. The results indicate that effects of number magnitude on duration estimation should not be attributed to the mathematical differences between numbers but to how the numbers are perceived to differ from each other in magnitude in specific contexts when they denote concrete items. The results also provide new evidence for the theoretical proposal of a common generalized magnitude system and indicate that the system must be extended to include other action-oriented magnitudes, such as weight.

The advantage of positive text-background polarity is due to high display luminance

Reading text from computer screens is better when text is printed in dark letters on light background (positive polarity) than when it is printed in light letters on dark background (negative polarity). An experiment is presented that tests whether this positive polarity advantage is due to the fact that overall display luminance is typically higher for positive than for negative polarity displays. To this end, text-background polarity and display luminance were manipulated independently. No positive polarity advantage was observed when overall display luminance of positive and negative polarity displays was equivalent. There was only an effect of display luminance, with better performance for the higher-luminance displays. This suggests that the positive polarity advantage is in fact due to the typically higher luminance of positive polarity displays. Readability of text presented on computer screens (e.g. on websites) is better when the overall display luminance level is high, as in positive polarity displays (dark letters on light background). Display polarity per se does not affect readability.

Corroborating biased indicators: global and local agreement among objective and subjective estimates of printed word frequency

The internal validity of several types of experiments in experimental psychology and neuroscience depends in part on the possibility of controlling or manipulating critical lexical variables such as word frequency of occurrence. Two ways of estimating this variable are (1) objective frequency counts and (2) subjective ratings of word frequency. Each method produces estimates that generally agree (i.e., they are highly correlated) but that disagree substantially concerning the relative frequency of a number of words. To investigate this issue more closely, the global and local agreement of subjective frequency estimates was examined in detail for a pool of 6,202 words drawn from the OMNILEX database of French words (Desrochers, 2006; www.omnilex.uottawa.ca). The results indicated that objective and subjective frequencies are strongly correlated, subjective frequencies share a significant amount of bias variance with other lexical characteristics (e.g., imageability), and the codeterminants of subjective frequency are in an antagonistic relationship with one another. The implications of these results for the selection of lexical stimuli are discussed, and multiple variables to aid in item selection are reported. Supplemental materials for this study may be downloaded from brm.psychonomic-journals.org/content/supplemental.

The Wisdom of Individuals: Exploring People's Knowledge About Everyday Events Using Iterated Learning

Determining the knowledge that guides human judgments is fundamental to understanding how people reason, make decisions, and form predictions. We use an experimental procedure called ''iterated learning,'' in which the responses that people give on one trial are used to generate the data they see on the next, to pinpoint the knowledge that informs people's predictions about everyday events (e.g., predicting the total box office gross of a movie from its current take). In particular, we use this method to discriminate between two models of human judgments: a simple Bayesian model (Griffiths & Tenenbaum, 2006) and a recently proposed alternative model that assumes people store only a few instances of each type of event in memory (MinK; Mozer, Pashler, & Homaei, 2008). Although testing these models using standard experimental procedures is difficult due to differences in the number of free parameters and the need to make assumptions about the knowledge of individual learners, we show that the two models make very different predictions about the outcome of iterated learning. The results of an experiment using this methodology provide a rich picture of how much people know about the distributions of everyday quantities, and they are inconsistent with the predictions of the MinK model. The results suggest that accurate predictions about everyday events reflect relatively sophisticated knowledge on the part of individuals.

Spatial ensemble statistics are efficient codes that can be represented with reduced attention

There is a great deal of structural regularity in the natural environment, and such regularities confer an opportunity to form compressed, efficient representations. Although this concept has been extensively studied within the domain of low-level sensory coding, there has been limited focus on efficient coding in the field of visual attention. Here we show that spatial patterns of orientation information ("spatial ensemble statistics") can be efficiently encoded under conditions of reduced attention. In our task, observers monitored for changes to the spatial pattern of background elements while they were attentively tracking moving objects in the foreground. By using stimuli that enable us to dissociate changes in local structure from changes in the ensemble structure, we found that observers were more sensitive to changes to the background that altered the ensemble structure than to changes that did not alter the ensemble structure. We propose that reducing attention to the background increases the amount of noise in local feature representations, but that spatial ensemble statistics capitalize on structural regularities to overcome this noise by pooling across local measurements, gaining precision in the representation of the ensemble.

Implicit perception and level of processing in object-substitution masking

Object-substitution masking (OSM) refers to reduced target discrimination when the target is surrounded by a sparse mask that does not overlap with the target in space but trails it in time. In four experiments, we used a novel paradigm to investigate the extent of processing of a masked target in OSM. We measured response-compatibility effects between target and mask, both when the offsets were simultaneous and when the offset of the mask was delayed. Evidence for both OSM and a dissociation between perception and awareness was found when detecting the match between the target and the mask required feature but not categorical analyses. Our results suggest that the locus of disruption in OSM is likely to be beyond feature analysis of the unreported target.

Datenanalyse: Das Null-Ritual und der Umgang mit Effekten in der Zeitschrift für Sportpsychologie

Zusammenfassung. Ziel dieses Beitrages ist die Analyse der Anwendung empirischer Tests in der deutschsprachigen Sportpsychologie. Die Ergebnisse vergleichbarer Analysen, bspw. in der Psychologie, zeigen, dass zwischen Anforderungen aus Testkonzepten und empirischer Realität Unterschiede existieren, die bislang für die Sportpsychologie nicht beschrieben und bewertet worden sind. Die Jahrgänge 1994–2007 der Zeitschrift für Sportpsychologie (früher psychologie und sport) wurden danach untersucht, ob Forschungsfragen formuliert, welche Stichprobenart gewählt, welches Testkonzept verwendet, welches Signifikanzniveau benutzt und ob statistische Probleme diskutiert wurden. 83 Artikel wurden von zwei unabhängigen Bewertern nach diesen Aspekten kategorisiert. Als Ergebnis ist festzuhalten, dass in der sportpsychologischen Forschung überwiegend eine Mischung aus Fishers Signifikanztesten sowie Neyman-Pearsons-Hypothesentesten zur Anwendung kommt,das sogenannte „Hybrid-Modell” oder „Null-Ritual”. Die Beschreibung der Teststärke ist kaum zu beobachten. Eine zeitliche Analyse der Beiträge zeigt, dass vor allem die Benutzung von Effektgrößen in den letzten Jahren zugenommen hat. Abschließend werden Ansätze zur Verbesserung und der Vereinheitlichung der Anwendung empirischer Tests vorgeschlagen und diskutiert.

Sudden death and gradual decay in visual working memory

General Douglas MacArthur remarked that "old soldiers never die; they just fade away." For decades, researchers have concluded that visual working memories, like old soldiers, fade away gradually, becoming progressively less precise as they are retained for longer periods of time. However, these conclusions were based on threshold-estimation procedures in which the complete termination of a memory could artifactually produce the appearance of lower precision. Here, we use a recall-based visual working memory paradigm that provides separate measures of the probability that a memory is available and the precision of the memory when it is available. Using this paradigm, we demonstrate that visual working memory representations may be retained for several seconds with little or no loss of precision, but that they may terminate suddenly and completely during this period.

Gamma flicker triggers attentional selection without awareness

Gamma band modulations in neural activity have been proposed to mediate attentional processes. To support a causal link between gamma activity and attentional selection, we attempt to evoke gamma oscillations by a 50-Hz subliminal flicker. We find that a subliminal 50-Hz flicker at a target location, before target presentation, speeds up and enhances target detection and discrimination. This effect is specific to the middle of the gamma range because it is not evident at <35-Hz flicker. It requires 300 ms to build up, dissipates within 250 ms of flicker offset, and shows a tendency to invert after 500 ms. The results are discussed in relation to a role for gamma band neural synchrony in the allocation of visual attention.