Stability and flexibility are essential components of cognitive control, critical for goal-directed behavior and adaptability, particularly in children. However, the relationship between them is debated; traditional unidimensional models suggest a trade-off relationship, while recent studies propose a two-dimensional perspective emphasizing their independence. Previous research mostly focused on adults, overlooking the rapid development of stability and flexibility in children. The current study recruited 38 adults and 73 healthy children aged 9–10 years to investigate the relationship between stability and flexibility in both intra-task (Experiments 1 and 2) and inter-task (Experiment 3) contexts. Experiments 1 and 2 utilized a rule-switching task with stimulus-response consistency manipulation: switch costs measured flexibility, while the consistency effect assessed stability. Both results of Experiments 1 and 2 supported a two-dimensional model for cognitive stability and flexibility in the intra-task context. Experiment 3 employed the color-word Stroop task to measure cognitive stability (congruency effect), and an inter-task correlational analysis was conducted with the switch costs (flexibility indicator) from Experiment 2. The findings revealed no significant correlation between the Stroop congruency effect and rule-switching costs, indicating independence between stability and flexibility in different task contexts, further supporting the two-dimensional model in the inter-task context. In conclusion, this study supports the independence of cognitive stability and flexibility during middle childhood, demonstrating their ability to coexist at high levels based on task demands. These insights deepen our understanding of cognitive control in children and provide a theoretical foundation for offering developmental guidance and developing effective cognitive training programs.
Neural noise is an unavoidable byproduct of brain function. Rather than noise being merely an unavoidable limitation, accumulating evidence suggests it may serve a functional role in maintaining optimal neural processing. Some theoretical accounts suggest that the brain may modulate its noise level to achieve this; however, experimental and computational evidence that illustrates this dynamic nature of neural noise is limited. Here, we investigated whether the brain aims to optimise its neural noise levels in response to task demands using a visual letter identification task with varying stimulus contrast. Computational modelling predicted conditions where counterintuitive increases in neural noise should lead to optimal performance. We tested this prediction experimentally, estimating neural noise using an N-pass paradigm. Results revealed that lower stimulus contrasts (i.e., more difficult perceptual conditions) were associated with higher neural noise, suggesting that the brain adapts and modulates its internal variability depending on sensory demands to enhance performance. Overall, our results support the notion that the brain's neural noise is contextually flexible and may serve an adaptive role, which reflects the brain's ability to adapt to changing perceptual demands.
Distinguishing objects from the background, a process known as Object Individuation (OI), is fundamental for us to interact with the environment and relies critically on location information across sensory modalities. Nonetheless, it remains unclear and contested in the literature whether the enumeration of tactile and visual events relies on the OI process (especially given spatial constraints), or if the representation of numerosity is governed by a modality-independent mechanism common to both visual and tactile systems. In this study, we used a cross-modal enumeration and a working memory dual-task paradigm to investigate whether OI processes in tactile and visual modalities draw upon a shared cognitive resource. We implemented two experiments. In Experiment 1, we combined a tactile working memory (WM) task with visual enumeration, and in Experiment 2, we used a visual WM task with tactile enumeration. Both experiments revealed that the task-irrelevant WM load significantly modulated subitizing performance (enumeration of small quantities) in the target modality. Under high WM load, participants showed increased error rates and reduced subitizing capacity compared to low load. This modulation is selective to the subitizing range and cannot be attributed to general dual-task costs, ruling out general dual-tasking effects. The data shows that visual and tactile working memory and enumeration ("subitizing") share a common OI process that operates on location, independent of the sensory modality. This finding is consistent with existent neuroimaging evidence that highlights the modality-shared role of frontoparietal brain regions (e.g., IPS, LPFC) in enumeration and working memory.
Children typically prefer the so-called "basic"-level (e.g., dog) versus narrower subordinate (e.g., dalmatian) meanings in acquisition. Subordinate conjectures are facilitated by contrast; for example, when shown a dalmatian and a corgi each labelled "dax" and "wug," learners take "dax" to mean dalmatian, as opposed to dog. But what is the nature of this effect? On a pragmatic account, contrast is helpful because it highlights a communicative pressure on the speaker to be more informative than usual when describing the target referent, given relevant alternatives. Another possibility, however, is that contrastive forms create a simple lexical heuristic. We raise and test two predictions that follow from the pragmatic, but not the lexical, account: in learning subordinate nouns, children use contrastive information even when there are no competing lexical labels (Exp. 1); furthermore, they consider the speaker's knowledge of contrasting alternatives during word learning, as a fully Gricean rich-computation model expects (Exp. 2). Results support a pragmatic (over a purely lexical) account of subordinate conjectures. Thus subordinate noun learning offers an early demonstration of children's ability to integrate informativeness with the speaker's epistemic state during word learning.
Adaptive control-the ability to modulate attention based on contextual demands-is typically assumed to be a domain-general cognitive function. The function's actual domain-generality, however, remains unclear, as confound-controlled evidence for adaptive control is presently limited to the interference tasks used to examine it (typically, Stroop tasks) and the stimuli used in those tasks (typically, words and colors). We addressed these limitations by conducting a systematic examination of adaptive control in the three main interference-task types in the cognitive-control literature (i.e., Stroop, Stroop-like, and Simon, which are defined in terms of the degree of overlap between the targets, distractors, and responses used in those tasks) while varying the stimuli used in the tasks. The adaptive-control index we used was the Proportion-Congruent (PC) effect-the finding that, on confound-controlled trials, the effect of the distractor's congruency with the target on response time and accuracy is larger when the two are frequently congruent (e.g., RED in red) than when they are frequently incongruent (e.g., RED in blue). Across five experiments and seven different tasks with young adults (N = 432), we found robust PC effects in Stroop and Simon task types (in both types the distractor-associated response can conflict with the target-associated response) but not in Stroop-like task types (in which response conflict plays a weaker role). These findings establish the domain-generality of adaptive control but also suggest that response conflict is important for triggering adaptive control, a boundary condition that challenges extant adaptive-control models and will need consideration when revising them.
