Semantic generalization of stimulus-task bindings

People find it difficult to switch between two tasks, even if they have time to prepare—the so-called residual task shift cost. We studied a switch of tasks from picture naming to word reading, using picture-word Stroop stimuli. Consistent with previous findings, we demonstrate that a large part of the observed task shift cost was due to priming from prior stimulus-response episodes, in which the current task stimulus was encountered in a competing task. We further show that this task-priming effect generalizes to semantically related stimuli, which opens the possibility that most or all of these residual shift costs reflect some sort of generalized proactive interference from previous stimulus-task episodes.     

Group interventions for patients with cancer and HIV disease: part IV. Clinical and policy recommendations

Group interventions have assumed a growing role in primary prevention and supportive care for cancer and HIV disease. Earlier sections of this Special Report examined empirical findings for these interventions and provided recommendations for future research. The current section offers brief recommendations for service providers, policymakers, and stakeholders. Group services now occupy an increasingly prominent place in primary prevention programs and medical settings. In previous sections of this Special Report (Sherman, Leszcz et al., 2004; Sherman, Mosier et al., 2004a, 2004b) we examined the efficacy of different group interventions at different phases of cancer or HIV disease, considered characteristics of the intervention and the participants that might influence outcomes, and discussed mechanisms of action. Methodological challenges and priorities for future research were highlighted. In this, the final section, we offer brief recommendations for service providers, policymakers, and other stakeholders. We consider some of the barriers that constrain use of empirically-based group interventions and note how these programs might be implemented more widely and effectively.     

How the brain blinks: towards a neurocognitive model of the attentional blink

When people monitor a visual stream of rapidly presented stimuli for two targets (T1 and T2), they often miss T2 if it falls into a time window of about half a second after T1 onset-the attentional blink (AB). We provide an overview of recent neuroscientific studies devoted to analyze the neural processes underlying the AB and their temporal dynamics. The available evidence points to an attentional network involving temporal, right-parietal and frontal cortex, and suggests that the components of this neural network interact by means of synchronization and stimulus-induced desynchronization in the beta frequency range. We set up a neurocognitive scenario describing how the AB might emerge and why it depends on the presence of masks and the other event(s) the targets are embedded in. The scenario supports the idea that the AB arises from "biased competition", with the top-down bias being generated by parietal-frontal interactions and the competition taking place between stimulus codes in temporal cortex.     

Second to fourth digit ratio and numerical competence in children

The ratio between the 2nd and 4th fingers (2D:4D)-a potential proxy for prenatal testosterone (T) exposure-shows a sex difference, with males usually having lower mean values; the latter potentially indicates higher prenatal T exposure. We studied relations between 2D:4D and competencies in the domains of counting, number knowledge, and visual-number representation in 73 children aged 6-11 years. Significant negative correlations between numerical performance in all of these areas and right and left hand 2D:4D ratios were found for boys but not girls. To the extent that 2D:4D ratios reflects prenatal exposure to T, the implications are (i) high prenatal T may be associated with better performance on some basic numerical measures for boys, and (ii) prenatal exposure to T may affect boys and girls differently with respect to some numerical competencies.     

Successive olfactory reversal learning in honeybees

Honeybees Apis mellifera can associate an originally neutral odor with a reinforcement of sucrose solution. Forward pairings of odor and reinforcement enable the odor to release the proboscis extension reflex in consecutive tests. Bees can also be conditioned differentially: They learn to respond to a reinforced odor and not to a nonreinforced one. They can also learn to reverse their choice. Here we ask whether honeybees can learn successive olfactory differential conditioning tasks involving different overlapping pairs of odors. The conditioning schedules were established in order to train the animals with 3, 2, 1, or 0 reversals previous to a last differential conditioning phase in which two additional reversals were present. We studied whether or not successive reversal learning is possible and whether or not learning olfactory discrimination reversals affects the solving of subsequent discrimination reversals. Therefore we compared the responses of bees that had experienced reversals with those of bees that had not experienced such reversals when both are confronted with a new reversal situation. In experiment 1 we showed that bees that had experienced three previous reversals were better in solving the final reversal task than bees with no previous reversal experience. In experiment 2, we showed that one reversal learning is enough for bees to perform better in the final reversal task. The successive different reversals trained in our experiments resemble the natural foraging situation in which a honeybee forager has to switch successively from an initial floral species to different ones. The fact that experiencing such changes seems to improve a bee's performance in dealing with further new exploited food sources has therefore an adaptive impact for the individual and for the colony as a whole.     

Task-switching and long-term priming: role of episodic stimulus-task bindings in task-shift costs

When subjects switch between two tasks, performance is slower after a task switch than after a task repetition. We report five experiments showing that a large part of these "task-shift-costs" cannot be attributed to a control operation, needed to configure the cognitive system for the upcoming task (e.g., ). In all experiments subjects switched between picture-naming and word-reading. We presented different stimuli either in just one of the two tasks, or in both of them. Shift-costs were larger for stimuli presented in both tasks than for those presented in only one task, even after more than 100 intervening trials between prime and probe events. We suggest (as proposed by ) that stimuli acquire associations with the tasks in which they occur. When the current task activation is weak, as on a switch of tasks, stimuli can trigger retrieval of the associated, competing task, provoking larger time costs.     

Introducing the Collective Action Recursive Empowerment (CARE) Model: How Small-Scale Protests Led to Large-Scale Collective Action in Armenia's Velvet Revolution

The current study examined the motivations and outcomes of the Armenian Velvet Revolution through the voice of 18 protesters with qualitative interviews, exploring their motivations for joining the collective action, their perceptions of its implementation, and resultant psychological changes. Participants distinguished between individual- and group-level processes and bypassed social divisions through a shared belief in the value of “Rejecting Serzh” (i.e., opposing then President Serzh Sargsyan). Results also illustrated a recursive process of collective action supporting the development of a new theoretical CARE (collective action recursive empowerment) model. The model understands successful social change as a function of both individual and group identity informing collective-action processes: Smaller acts of protest increase individual feelings of shared group identity and empowerment/efficacy beliefs, thus strengthening motivations for continued protest and making large-scale collective action achievable. By linking together multiple time points of a collective-action process in one recursive model, the current work maps out one specific case of successful collective action in recent history, which serves as a basis for broader theoretical generalization and future empirical research.     

Bad things come easier to the mind but harder to the body: Evidence from brain oscillations

An intriguing finding of research on emotional processing is a discrepancy between perception and behavior. Perceptually, a robust finding is that negative stimuli are processed faster and more efficiently than positive stimuli. Behaviorally, a similarly robust finding is that response times are slower for negative than for positive stimuli. We proposed and tested a novel account to explain this still unexplained discrepancy, on the basis of the assumption that negative valence narrows perceptual processes to the benefit of speeded perception, but broadens motor processes at the cost of slowed responding. Participants performed a valence judgment task in which they responded with their left or right hand to negative and positive stimuli that were presented on the left or right, and we measured the activation of relevant/deactivation of irrelevant perceptual and motor processes, as revealed by the lateralization of electroencephalographic brain oscillations. Stimulus-related lateralization of alpha activity (8–12 Hz) over perceptual areas was increased for negative stimuli, indicating more efficient perceptual processing. By contrast, response-related lateralization of beta activity (20–25 Hz) over motor areas was decreased for negative stimuli, indicating less efficient response activation. Consistent with our predictions, more detailed analyses showed that both lateralization effects were caused by dynamics at the level of inhibiting irrelevant processes. For negative as compared to positive stimuli, the inhibition of irrelevant perceptual processes was increased, but the inhibition of irrelevant motor processes was decreased. These findings indicate that the discrepancy between perception and behavior in emotional processing may stem from asymmetrical effects of emotional valence on the breadth of cortical activations in perceptual and motor networks.