Reinforcement: Food Signals the Time and Location of Future Food

It has long been understood that food deliveries may act as signals of future food location, and not only as strengtheners of prefood responding as the law of effect suggests. Recent research has taken this idea further—the main effect of food deliveries, or other “reinforcers”, may be signaling rather than strengthening. The present experiment investigated the ability of food deliveries to signal food contingencies across time after food. In Phase 1, the next food delivery was always equally likely to be arranged for a left‐ or a right‐key response. Conditions were arranged such that the next food delivery was likely to occur either sooner on the left (or right) key, or sooner on the just‐productive (or not‐just‐productive) key. In Phase 2, similar contingencies were arranged, but the last‐food location was signaled by a red keylight. Preference, measured in 2‐s bins across interfood intervals, was jointly controlled by the likely time and location of the next food delivery. In Phase 1, when any food delivery signaled a likely sooner next food delivery on a particular key, postfood preference was strongly toward that key, and moved toward the other key across the interreinforcer interval. In other conditions in which food delivery on the two keys signaled different subsequent contingencies, postfood preference was less extreme, and quickly moved toward indifference. In Phase 2, in all three conditions, initial preference was strongly toward the likely‐sooner food key, and moved to the other key across the interfood interval. In both phases, at a more extended level of analysis, sequences of same‐key food deliveries caused a small increase in preference for the just‐productive key, suggesting the presence of a “reinforcement effect”, albeit one that was very small.     

The influence of delaying judgments of learning on metacognitive accuracy: a meta-analytic review

Many studies have examined the accuracy of predictions of future memory performance solicited through judgments of learning (JOLs). Among the most robust findings in this literature is that delaying predictions serves to substantially increase the relative accuracy of JOLs compared with soliciting JOLs immediately after study, a finding termed the delayed JOL effect. The meta-analyses reported in the current study examined the predominant theoretical accounts as well as potential moderators of the delayed JOL effect. The first meta-analysis examined the relative accuracy of delayed compared with immediate JOLs across 4,554 participants (112 effect sizes) through gamma correlations between JOLs and memory accuracy. Those data showed that delaying JOLs leads to robust benefits to relative accuracy (g = 0.93). The second meta-analysis examined memory performance for delayed compared with immediate JOLs across 3,807 participants (98 effect sizes). Those data showed that delayed JOLs result in a modest but reliable benefit for memory performance relative to immediate JOLs (g = 0.08). Findings from these meta-analyses are well accommodated by theories suggesting that delayed JOL accuracy reflects access to more diagnostic information from long-term memory rather than being a by-product of a retrieval opportunity. However, these data also suggest that theories proposing that the delayed JOL effect results from a memorial benefit or the match between the cues available for JOLs and those available at test may also provide viable explanatory mechanisms necessary for a comprehensive account.     

Thinking About the Future as a Way to Succeed in the Present: A Longitudinal Study of Future Orientation and Violent Behaviors Among African American Youth

Previous research has linked higher levels of hopelessness about one's future to violent behavior during adolescence; however, little is known about this relationship over time for adolescents. Using growth curve modeling, we tested the association between future orientation and violent behavior across the high school years of adolescence in a sample of African American youth (n = 681). Variation based on demographic characteristics (i.e., sex, SES, previous violence) was explored. At baseline, differences in violent behavior varied by demographic characteristics. Overall, violent behavior decreased with age. Higher levels of future orientation were associated with greater decreases in violent behavior over time. Demographic characteristics were not associated with change in violent behavior overtime. Our findings suggest that future orientation can act as a promotive factor for at risk African American youth. Interventions that help support the development of future goals and aspirations could play a vital role in violence prevention efforts.     

Youth Empowerment in Context: Exploring Tensions in School-Based yPAR

In much of the youth empowerment literature, researchers focus on the relationship between youth and adults involved in empowerment programs while neglecting the broader social framework in which these relationships and the program itself functions. Utilizing an ecological model, the current research examines the tensions that surfaced in attempts to create an empowering setting in an after-school PAR program with fifth-graders. Challenging assumptions about youth, structural challenges, and conflicting theories of change are highlighted. Results examine the role of sociocultural context as PAR researchers attempt to create a setting in which students gain skills to become change agents within their school. The study suggests that youth empowerment is a context dependent process that requires attention to a multiplicity of factors that influence possibilities for empowerment via second order change.     

From the Macro to the Micro: A Geographic Examination of the Community Context and Early Adolescent Problem Behaviors

This study examined how multiple dimensions and levels of the community context associated with early adolescent problem behaviors in rural communities. Four thousand, five hundred and nine eighth-grade students in 28 rural and small town school districts in two states participated in surveys regarding substance use and delinquency in 2005. Locations of alcohol retailers, tobacco retailers, youth-serving organizations, and student residences were geocoded. Associations of the number of proximal alcohol and tobacco retailers, and youth-serving organizations with an early-adolescent problem behavior index were tested in Nonlinear Mixed Models that controlled for multiple district-level and individual characteristics. Multi-level model results demonstrated that the number of alcohol and tobacco retail locations within a one-mile radius of each adolescent's home positively associated with student-reported problem behaviors above and beyond the influence of school district and individual characteristics. Results suggest that the proximal community context added significantly to the district context when understanding the occurrence of early adolescent problem behaviors. Recognizing this variability in geographically determined risk within a community will likely enhance the effectiveness of community prevention activities.     

Children's memories for events relating to treatment for eye cancer: Influence of age at loss of eye

Treatment for retinoblastoma frequently involves removal of at least one eye in the first 5 years. Variation in age of treatment leads to the assumption that children's later verbal accessibility of early traumatic memories may vary, with some children having less opportunity to make sense of their condition. Video recordings were made of 17 children who had undergone enucleation either before 24 months (n = 8) or after 24 months (n = 9) involved in “hospital play'' using props designed to elicit talk about “eyes.” The hypothesis that a larger number of verbalizations about medical procedures would occur in children enucleated after 24 months than before 24 months was supported. Children enucleated after 24 months engaged in significantly more talk about enucleation and/or examination under anesthetic whereas none of the children enucleated in infancy talked about these medical events. The outcome supports the view that there is a transition around 24 months in the extent to which children can have verbal access to previous traumatic memories. The design of interventions needs to take into account that children enucleated in infancy have less opportunity for later verbal access to early memories of traumatic events than those treated later, leading to possible misconceptions about their own condition.     

The cortisol awakening response: Associations with trait anxiety and stress reactivity

This study investigated the extent to which trait anxiety and state anxiety in response to stress are associated with the cortisol awakening response (CAR).Fifty-one healthy participants were recruited. State anxiety measures were taken in anticipation of and during a laboratory stressor. Salivary cortisol levels were measured immediately upon awakening (at 0, 15, 30, and 45 min) on two consecutive mornings. Cortisol awakening response was assessed by the area under the curve with respect to zero (AUC_G).The magnitude of the CAR was found to be negatively associated with both trait anxiety and anticipatory anxiety. Moreover, regression analysis showed that the effects of trait anxiety on the AUC_G were mediated by anticipatory anxiety.These results suggest that the CAR is influenced by trait anxiety. Moreover, the effect of trait anxiety on the CAR seems to operate by impacting on psychological stress reactivity (i.e., anticipatory anxiety).     

An fMRI investigation of a novel analogue to the Trail-Making Test

The Trail-Making Test (TMT) is a widely used neuropsychological measure that assesses visuomotor abilities and cognitive flexibility. For the TMT-A condition participants are required to locate and connect numbers (i.e. 1-2-3…) while in the TMT-B condition participants perform the set-shifting task of locating and connecting numbers and letters (i.e. 1-A-2-B…). The TMT-B condition has shown impairments in many clinical populations, particularly schizophrenia patients, but the neurobiological underpinning of the task can be difficult to discern given pragmatic obstacles in adapting the task for neuroimaging. In a behavioural testing experiment we demonstrated a close correspondence between performance on the standard TMT and a novel, computer programmed adaptation of the TMT (pcTMT). The pcTMT was designed for functional magnetic resonance imaging (fMRI) administration and neuroimaging data for this task were obtained in. A whole brain analysis revealed significantly greater activation during the pcTMT-B relative to the pcTMT-A in right inferior/middle frontal cortices, right precentral gyrus, left angular gyrus/left middle temporal gyrus. These results identify the regions that most likely underlie cognitive flexibility during the TMT and are candidate regions underlying the impairment of groups with poor set-shifting abilities.     

The importance of a visual horizon for distance judgments under severely degraded vision

In two experiments we examined the role of visual horizon information on absolute egocentric distance judgments to on-ground targets. Sedgwick [1983, in Human and Machine Vision (New York: Academic Press) pp 425-458] suggested that the visual system may utilize the angle of declination from a horizontal line of sight to the target location (horizon distance relation) to determine absolute distances on infinite ground surfaces. While studies have supported this hypothesis, less is known about the specific cues (vestibular, visual) used to determine horizontal line of sight. We investigated this question by requiring observers to judge distances under degraded vision given an unaltered or raised visual horizon. The results suggest that visual horizon information does influence perception of absolute distances as evident through two different action-based measures: walking or throwing without vision to previously viewed targets. Distances were judged as shorter in the presence of a raised visual horizon. The results are discussed with respect to how the visual system accurately determines absolute distance to objects on a finite ground plane and for their implications for understanding space perception in low-vision individuals.