Time takes space: selective effects of multitasking on concurrent spatial processing.

Many everyday activities require coordination and monitoring of complex relations of future goals and deadlines. Cognitive offloading may provide an efficient strategy for reducing control demands by representing future goals and deadlines as a pattern of spatial relations. We tested the hypothesis that multiple-task monitoring involves time-to-space transformational processes, and that these spatial effects are selective with greater demands on coordinate (metric) than categorical (nonmetric) spatial relation processing. Participants completed a multitasking session in which they monitored four series of deadlines, running on different time scales, while making concurrent coordinate or categorical spatial judgments. We expected and found that multitasking taxes concurrent coordinate, but not categorical, spatial processing. Furthermore, males showed a better multitasking performance than females. These findings provide novel experimental evidence for the hypothesis that efficient multitasking involves metric relational processing.

Deadlines in space: Selective effects of coordinate spatial processing in multitasking.

Many everyday activities require coordination and monitoring of multiple deadlines. One way to handle these temporal demands might be to represent future goals and deadlines as a pattern of spatial relations. We examined the hypothesis that spatial ability, in addition to executive functioning, contributes to individual differences in multitasking. In two studies, participants completed a multitasking session in which they monitored four digital clocks running at different rates. In Study 1, we found that individual differences in spatial ability and executive functions were independent predictors of multiple-task performance. In Study 2, we found that individual differences in specific spatial abilities were selectively related to multiple-task performance, as only coordinate spatial processing, but not categorical, predicted multitasking, even beyond executive functioning and numeracy. In both studies, males outperformed females in spatial ability and multitasking and in Study 2 these sex differences generalized to a simulation of everyday multitasking. Menstrual changes moderated the effects on multitasking, in that sex differences in coordinate spatial processing and multitasking were observed between males and females in the luteal phase of the menstrual cycle, but not between males and females at menses. Overall, these findings suggest that multiple-task performance reflects independent contributions of spatial ability and executive functioning. Furthermore, our results support the distinction of categorical versus coordinate spatial processing, and suggest that these two basic relational processes are selectively affected by female sex hormones and differentially effective in transforming and handling temporal patterns as spatial relations in the context of multitasking.

Age-related differences in multiple task monitoring.

Coordinating multiple tasks with narrow deadlines is particularly challenging for older adults because of age related decline in cognitive control functions. We tested the hypothesis that multiple task performance reflects age- and gender-related differences in executive functioning and spatial ability. Young and older adults completed a multitasking session with four monitoring tasks as well as separate tasks measuring executive functioning and spatial ability. For both age groups, men exceeded women in multitasking, measured as monitoring accuracy. Individual differences in executive functioning and spatial ability were independent predictors of young adults' monitoring accuracy, but only spatial ability was related to sex differences. For older adults, age and executive functioning, but not spatial ability, predicted multitasking performance. These results suggest that executive functions contribute to multiple task performance across the adult life span and that reliance on spatial skills for coordinating deadlines is modulated by age.

How crucial is the response format for the testing effect?

Combining study and test trials during learning is more beneficial for long-term retention than repeated study without testing (i.e., the testing effect). Less is known about the relative efficacy of different response formats during testing. We tested the hypothesis that overt testing (typing responses on a keyboard) during a practice phase benefits later memory more than covert testing (only pressing a button to indicate successful retrieval). In Experiment 1, three groups learned 40 word pairs either by repeatedly studying them, by studying and overtly testing them, or by studying and covertly testing them. In Experiment 2, only the two testing conditions were manipulated in a within-subjects design. In both experiments, participants received cued recall tests after a short (~19 min) and a long (1 week) retention interval. In Experiment 1, all groups performed equally well at the short retention interval. The overt testing group reliably outperformed the repeated study group after 1 week, whereas the covert testing group performed insignificantly different from both these groups. Hence, the testing effect was demonstrated for overt, but failed to show for covert testing. In Experiment 2, overtly tested items were better and more quickly retrieved than those covertly tested. Further, this does not seem to be due to any differences in retrieval effort during learning. To conclude, overt testing was more beneficial for later retention than covert testing, but the effect size was small. Possible explanations are discussed.

Hepatitis C among injecting drug users is two times higher in Stockholm, Sweden than in Rotterdam, the Netherlands.

This study assessed risk behavior and preventive measures for hepatitis C among injecting drug users in Rotterdam, the Netherlands (452 participants, 2002-2003) and Stockholm, Sweden (310 participants, 2004-2006), two cities with contrasting drug policies. Uni- and multivariate logistic regression models were used. We found that the prevalence of hepatitis C was almost two times higher in participants from Stockholm than in participants from Rotterdam, even after adjustment for sex sharing paraphernalia (adjusted relative risk: 1.92, 95% confidence interval: 1.60-2.29). Follow-up comparative studies are needed to determine if policies with structured health programs can decrease transmission of hepatitis C.

Study for now, but judge for later: delayed judgments of learning promote long-term retention.

Delayed judgments of learning (JOL) are assumed to be based on covert retrieval attempts. A common finding is that testing memory during learning improves later retention (i.e., the testing effect), and even more so than an equivalent amount of study, but only after a longer retention interval. To test the assertion that also delayed JOLs improve memory, the participants either studied Swahili-Swedish word pairs four times, or they both studied (two times) and performed delayed JOLs (two times) alternately. Final cued recall test were given after either five minutes or one week. Results showed a reliable learning-group by retention-interval interaction, with less forgetting in the group that alternated between studying and making JOLs. The results are discussed in relation to the self-fulfilling prophecy account of Spellman and Bjork (1992), and in terms of study advice, the results further underscore the importance of delaying JOLs when studying and evaluating one's ongoing learning.