The development of multitasking abilities was investigated in relation to working memory capacity, sustained attention, inhibition, and task switching. Using a new touch-screen task, 90 children aged 7-10 years were asked to monitor several timers running at different paces, and to press a button whenever a timer had completed its cycle. Results showed that a significant part of the variance in children's multitasking performance was explained by age, and performance increased significantly until about 8-9 years. Multitasking performance was generally affected by the number of tasks, but even more so in younger children. Sustained attention explained a significant part of the variance in triple-, but not dual-task performance; visuospatial working memory capacity explained variance in dual- and triple-task performance, even after controlling for age. In conclusion, multitasking develops considerably in middle childhood and may involve different processes than dualtasking.

Smiling is believed to make people look younger. Ganel and Goodale (Psychon Bull Rev 25(6):612–616, https://doi.org/10.3758/s13423-017-1306-8, 2018) proposed that this belief is a misconception rooted in popular media, based on their findings that people actually perceive smiling faces as older. However, they did not clarify whether this misconception can be generalized across cultures. We tested the cross-cultural validity of Ganel and Goodale’s findings by collecting data from Japanese and Swedish participants. Specifically, we aimed to replicate Ganel and Goodale’s study using segregated sets of Japanese and Swedish facial stimuli, and including Japanese and Swedish participants in groups asked to estimate the age of either Japanese or Swedish faces (two groups of participants × two groups of stimuli; four groups total). Our multiverse analytical approach consistently showed that the participants evaluated smiling faces as older in direct evaluations, regardless of the facial stimuli culture or their nationality, although they believed that smiling makes people look younger. Further, we hypothesized that the effect of wrinkles around the eyes on the estimation of age would vary with the stimulus culture, based on previous studies. However, we found no differences in age estimates by stimulus culture in the present study. Our results showed that we successfully replicated Ganel and Goodale (2018) in a cross-cultural context. Our study thus clarified that the belief that smiling makes people look younger is a common cultural misconception.

Retrieval practice improves long-term retention. However, it is currently debated if this testing effect can be further enhanced by overtly producing recalled responses. We addressed this issue using a standard cued-recall testing-effect paradigm with verb–noun action phrases (e.g., water the plant) to prompt motor actions as a specifically powerful response format of recall. We then tested whether motorically performing the recalled verb targets (e.g., ?–the plant) during an initial recall test (enacted retrieval) led to better long-term retention than silently retrieving them (covert retrieval) or restudying the complete verb–noun phrases (restudy). The results demonstrated a direct testing effect, in that long-term retention was enhanced for covert retrieval practice compared to restudy practice. Critically, enactment during retrieval further improved long-term retention beyond the effect of covert memory retrieval, both in a congruent noun-cued recall test after 1 week (Experiment 1) and in an incongruent verb-cued recall test of nouns after 2 weeks (Experiment 2). This finding suggests that successful memory retrieval and ensuing enactment contribute to future memory performance in parts via different mechanisms.

Most everyday activities involve delayed intentions referring to different event structures and timelines. Yet, past research has mostly considered prospective memory (PM) as a dual-task phenomenon in which the primary task to fulfill PM intentions is realized within an ongoing secondary task. We hypothesized that these simplified simulations of PM may have obscured the role of spatial relational processing that is functional to represent and meet the increased temporal demands in more complex PM scenarios involving multiple timelines. To test this spatiotemporal hypothesis, participants monitored four digital clocks, with PM deadlines referring either to the same clock (single-context condition) or different clocks (multiple-context condition), along with separate tests of spatial ability (mental rotation task) and executive functioning (working memory updating). We found that performance in the mental rotation task incrementally explained PM performance in the multiple-context, but not in the single-context, condition, even after controlling for individual differences in working memory updating and ongoing task performance. These findings suggest that delayed intentions occurring in multiple ongoing task contexts reflect independent contributions of working memory updating and mental rotation and that spatial relational processing may specifically be involved in higher cognitive functions, such as complex PM in multiple contexts or multitasking.

Proactively coordinating one's actions is an important aspect of multitasking performance due to overlapping task sequences. In this study, we used fMRI to investigate neural mechanisms underlying monitoring of multiple overlapping task sequences. We tested the hypothesis that temporal control demands in multiple-task monitoring are offloaded onto spatial processes by representing patterns of temporal deadlines in spatial terms. Results showed that increased demands on time monitoring (i.e., responding to concurrent deadlines of one to four component tasks) increasingly activated regions in the left inferior parietal lobe and the precuneus. Moreover, independent measures of spatial abilities correlated with multiple-task performance beyond the contribution of working memory. Together, these findings suggest that monitoring and coordination of temporally overlapping task timelines rely on cortical processes involved in spatial information processing. We suggest that the precuneus is involved in tracking of multiple task timelines, whereas the inferior parietal lobe constructs spatial representations of the temporal relations of these overlapping timelines. These findings are consistent with the spatial offloading hypothesis and add new insights into the neurocognitive mechanisms underlying the coordination of multiple tasks.

Metacognitive processes in human timing behavior are rarely investigated, which stands in sharp contrast to the wide research field of metacognition itself. To date, little is known about the sources and the reliability of information that humans possess to judge their own timing abilities and to monitor errors in time-keeping. Here, we intended to fill this gap by determining the degree to which humans depend on external feedback to adjust their timing behavior and make metacognitive accuracy judgments. Two groups of participants performed a time reproduction task under different feedback conditions. After each trial, participants were informed either about the magnitude and the direction of their timing error (signed feedback group) or about its magnitude alone (absolute feedback group). Reproduction errors were related to retrospective, metacognitive judgments on the overall timing performance. The results indicate that the under reproduction effect occurred, rather independently of the type of feedback; however, signed feedback was essential to reduce the bias in metacognitive judgments on timing accuracy. Without being explicitly informed about the direction of timing errors (whether the reproduction interval was stopped too early or too late), participants significantly overestimated their reproduced durations. These results extend previous reports of metacognitive processes in timing behavior measured on a single-trial basis, and provide new insights into the ability of temporal error monitoring in humans.

A large body of research referred to as “multitasking” is based on dual-task paradigms, focusing on cognitive bottlenecks and crosstalk between perceptual encoding and response selection processes. However, everyday multitasking is different from the microstructure of rapid switching between laboratory tasks, and cognitive bottlenecks may be avoided by scheduling and interleaving deadlines and other task constraints in order to achieve multiple goals. 

We suggest that executive control demands of coordinating multiple ongoing activities can be alleviated by representing patterns of temporal deadlines in spatial relations. This spatial offloading hypothesis is consistent with observations showing that temporal relations are often represented in spatial terms. Our own behavioural studies show that spatial ability (mental rotation) predicts multitasking, but not dual-task, performance beyond individual differences in executive functions. 

Here, we test central predictions of the spatial offloading hypothesis using functional neuroimaging. We expect that cortical areas associated with spatial processing are selectively activated during multitasking. Moreover, these effects should reflect temporal task complexity, with accentuated patterns of activation in multiple tasks, but not in single- and dual-task performance, in which demands on cognitive control and temporal coordination are reduced. 

Twenty-four healthy, young adults completed a time-based monitoring task with varying number of component tasks (single, dual and multiple series of letters, running at different rates), while neural activity was measured using fMRI.

Results show increased activation with increasing number of component tasks in posterior parietal brain regions related to spatial processing. These findings suggest that multitasking involves spatial abilities and their underlying neural correlates.

Coordinating multiple tasks requires a high degree of cognitive control, and individuals with limited executive functions often show difficulties in everyday multitasking. We tested the hypothesis that demands on executive control can be alleviated by internally representing the temporal pattern of goals and deadlines as spatial relations. In two experiments, participants completed a multitasking session by monitoring deadlines of four clocks running at different rates, along with separate tasks of executive functioning and spatial ability. In Experiment 1, individual and gender-related differences in spatial ability (mental rotation) predicted multitasking performance, beyond the contributions of both the updating and inhibition components of executive functioning, and even when spatial cues were eliminated from the layout of the monitoring task. Experiment 2 extended these findings by showing that concurrent spatial load impaired task monitoring accuracy, and that these detrimental effects were accentuated when spatial abilities were compromized due to fluctuation in female sex hormones. These findings suggest that multiple task monitoring involves working memory-related functions, but that these cognitive control demands can be offloaded by relying on spatial relation processes.

Successful retrieval from memory is a desirably difficult learning event that reduces the recall decrement of studied materials over longer delays more than restudying does. The present study was the first to test this direct testing effect for performed and read action events (e.g., light a candle) in terms of both recall accuracy and recall speed. To this end, subjects initially encoded action phrases by either enacting them or reading them aloud (i.e., encoding type). After this initial study phase, they received two practice phases, in which the same number of action phrases were restudied or retrieval-practiced (Exp. 1-3), or not further processed (Exp. 3; i.e., practice type). This learning session was ensued by a final cued-recall test both after a short delay (2 min) and after a long delay (1 week: Exp. 1 and 2; 2 weeks: Exp. 3). To test the generality of the results, subjects retrieval practiced with either noun-cued recall of verbs (Exp. 1 and 3) or verb-cued recall of nouns (Exp. 2) during the intermediate and final tests (i.e., test type). We demonstrated direct benefits of testing on both recall accuracy and recall speed. Repeated retrieval practice, relative to repeated restudy and study-only practice, reduced the recall decrement over the long delay, and enhanced phrases' recall speed already after 2 min, and this independently of type of encoding and recall test. However, a benefit of testing on long-term retention only emerged (Exp. 3), when prolonging the recall delay from 1 to 2 weeks, and using different sets of phrases for the immediate and delayed final tests. Thus, the direct testing benefit appears to be highly generalizable even with more complex, action-oriented stimulus materials, and encoding manipulations. We discuss these results in terms of the distribution-based bifurcation model.

Objectives: Processing of horizontal face cues has been shown to be an important element in face recognition of adults aged up to 30 years. In contrast, horizontally aligned facial features do not appear to contribute to older adults’ (60–75 years) recognition in a similar way. To this end, we investigated potential learning effects on the ability to recognize faces based on horizontal features. Previous research suggests face recognition based on all face information experiences an accelerated decline after the age of 70. However, recognition based only on horizontal face information has not yet been studied in old age (75+ years of age). Thus, we investigated whether older adults (aged up to as well as starting at 75 years) can learn to recognize faces based on horizontal face cues alone.

Method: One younger and two older adult groups (20–30, 60–75, and 75+ years) were familiarized with a high and a low amount of previously unfamiliar faces—some containing all face cues and others containing only horizontal face cues (reduced information). Subsequently, all groups received a recognition test.

Results: Repeated learning increased natural face recognition for all three age groups when all face cues were available. However, increases in face recognition were only observed for younger adults when horizontal face cued were only available.

Discussion: The importance of horizontally aligned spatial frequencies for recognizing human faces is lessened before the age of 60 (and plateaus thereon), whereas recognition of stimuli containing all face cues is still capable of improvement.