In the present study, participants performed highly comparable task-switching and dual-task paradigms, and the paradigm-specific performance costs were analysed in the context of the commonly postulated core components of cognitive control (i.e., working memory updating, inhibition, and shifting). In the task-switching paradigm, we found switch costs (i.e., switch trials vs. repetition trials) and mixing costs (i.e., repetition trials in mixed-task blocks vs. single-task trials). In the dual-task paradigm, we observed a psychological refractory period (PRP) effect (i.e., Task 2 [T2] performance after short stimulus-onset asynchrony [SOA] vs. long SOA), dual-task costs (i.e., T2 dual-task performance with a long SOA in trials with a task repetition between Task 1 [T1] and T2 vs. single-task performance), and switch costs in T2 (i.e., dual-task performance in trials with a switch between T1 and T2 vs. dual-task performance in trials with a repetition between T1 and T2). A with-in-subjects comparison of the performance costs showed a correlation between mixing costs and dual-task costs, possibly indicating shared underlying cognitive control processes in terms of working memory updating. Surprisingly, there was also a correlation between switch costs and the PRP effect, presumably suggesting that cognitive control, as opposed to passive queuing of response selection processes, contributes to the PRP effect.

The 18-item Need for Cognition Scale (NFC-18) is the most commonly used tool to measure the need for cognition. The aim of this study was to explore the possibility of developing an abbreviated version of the scale, applying the item response theory (IRT). Item response theory analyses suggested the exclusion of eight items that did not perform well in measuring the latent trait. The resulting 10-item scale (NFC-10), which included highly discriminative items, covered the same range of the measured trait as the original scale and showed high measurement precision along various levels of the trait. Additionally, since IRT analyses can only confirm the accuracy of the short scale in measuring the underlying construct, we sought to replicate the nomological net of the NFC-18 using the shortened version of the scale. The results showed that the NFC-10 reflects an adequate operationalization of the construct, in line with the longer version. In particular, as expected, the NFC-10 showed moderate relations with various measures of cognitive skills and self- report measures of cognitive styles, confidence, and anxiety. These findings confirm that we have obtained a much shorter version of the NFC that maintains excellent reliability and validity

The mental number line (MNL) is a popular metaphor for magnitude representation in numerical cognition. Its shape has frequently been reported as being nonlinear, based on nonlinear response functions in magnitude estimation. We investigated whether this shape reflects a phenomenon of the mapping from stimulus to internal magnitude representation or of the mapping from internal representation to response. In five experiments, participants (total N = 66) viewed stimuli that represented numerical magnitude either in a symbolic notation (i.e., Arabic digits) or in a nonsymbolic notation (i.e., clouds of dots). Participants estimated these magnitudes by either adjusting the position of a mark on a ruler-like response bar (nonsymbolic response) or by typing the corresponding number on a keyboard (symbolic response). Responses to symbolic stimuli were markedly different from responses to nonsymbolic stimuli, in that they were mostly power- shaped. We investigated whether the nonlinearity could be explained by effects of previous trials, but such effects were (a) not strong enough to explain the nonlinear responses and (b) existed only between trials of the same input notation, suggesting that the nonlinearity is due to input mappings. Introducing veridical feedback improved the accuracy of responses, thereby showing a calibration based on the feedback. However, this calibration persisted only temporarily, and responses to nonsymbolic stimuli remained nonlinear. Overall, we conclude that the nonlinearity is a phenomenon of the mapping from nonsymbolic input format to internal magnitude representation and that the phenomenon is surprisingly robust to calibration.

The ability to learn event sequences is crucial to human behavior because it enables us to interact adaptively with our environment. The sensory environment is essential in guiding the acquisition of these sequences, so the role of the stimulus modality in sequence learning is of high relevance. The present study examined structured stimulus modality shifts in sequence learning using the serial reaction time task (SRT). Participants had to respond to numbers that were presented either in the visual or in the auditory modality. Importantly, the numbers as well as the stimulus modality followed a fixed pattern. We found better performance in sequenced than in random blocks, indicating sequence learning. Moreover, performance was better when the stimulus modality remained the same than when the modality changed between successive trials (the modality shift effect, MSE). However, sequence learning facilitated performance primarily in modality repetitions, so that the MSE became progressively larger in the sequenced blocks, while it was small in the random blocks, and this pattern was particularly pronounced for the participants who showed a high recall level for the response sequence. To account for this effect, we assume that consistent modality shifts induce parsing of the sequence into chunks. Because chunk retrieval at chunk boundaries incurs RT costs, the acquired sequence knowledge is more efficiently expressed in modality repetitions (i.e., within chunks). Together, the data suggest that the formation of explicit knowledge enhances chunking in sequence learning.

We examined whether a general processing factor emerges when using response times for cognitive processing tasks and whether such a factor is valid across three different cultural groups (Chinese, Canadian, and Greek). Three hundred twenty university students from Canada (n = 115), China (n = 110), and Cyprus (n = 95) were assessed on an adaptation of the Das-Naglieri Cognitive Assessment System (D-N CAS; Naglieri & Das, 1997). Three alternative models were contrasted: a distinct abilities processing speed model (Model 1) that is dictated by the latent four cognitive factors of planning, attention, simultaneous and successive (PASS) processing, a unitary ability processing speed model (Model 2) that is dictated by the response time nature of all measures, and a bifactor model (Model 3) which included the latent scores of Models 1 and 2 and served as the full model. Results of structural equation modeling showed that (a) the model representing processing speed as a collection of four cognitive processes rather than a unitary processing speed factor was the most parsimonious, and (b) the loadings of the obtained factors were invariant across the three cultural groups. These findings enhance our understanding of the nature of speed of processing across diverse cultures and suggest that even when cognitive processes (i.e., PASS) are operationalized with response time measures, the processing component dominates speed.

Typing is an everyday activity that requires people to use the correct serial order of phonological and orthographic forms of words. The evidence until now shows that different forms of representation of serial order have mixed contributions to typing performance. It is not clear whether and how representational overlap between subsequent words impacts the speed of typing. In three experiments, we used speeded typing of six-letter words. Including conditions with secondary task load to counteract potential ceiling effects, we varied whether subsequent words had partial overlap with respect to a chaining representation (e.g., kirsch → schaum; same triplet in different position) or, in addition, overlapped with respect to a potential positional representation (e.g., berlin → dublin, same triplet in the same position). Differently from previous findings (e.g., Snyder & Logan, 2014), Experiments 1 and 2 suggest that (a) chaining as well as positional coding are involved as representations of serial order and (b) partial overlap of representation of serial order leads to costs in typing speed. Experiment 3 demonstrated that full overlap speeds up typing. Across all experiments, the overlap effects were most revealed in the latency of the first keystroke, indicating the planning of motor programs. Taken together, the results suggest that even in highly practiced tasks such as typing, the activation of representations of serial order has side effects beyond the production of the current sequence.

The issue of pictorial or propositional nature of imagery remains unresolved. To take a step for- ward into the debate, we conducted a systematic evaluation of time and accuracy of mental scaling in sighted people. Participants viewed or touched three-dimensional objects and then had to imagine them in a resized version, depending on a given scale. Both the mental scaling time and the estimated object size were measured. To promote verbal or perceptual strategies, the size was estimated verbally or bimanually, respectively. It was found that time taken for mental scaling is a linear function of decreasing and increasing scale and that the modality of perception did not influence the time taken to perform the operation. The results contribute to the knowledge of object size estimation by revealing the interaction between the modality of the object perception and the accuracy of size estimation by sighted adults. The accuracy of estimation was greater when the imagery representation was based on visual rather than tactile perception, but only in the case of verbal size assessment. Verbal height estimation in centimeters showed a tendency towards underestimation, while bimanually estimated sizes tended to be overestimated. The results indicate that people can use pictorial as well as prepositional strategies, depending on the task.