Time is one of the fundamental dimensions of the world. Correspondingly, duration perception is also crucial for everyday activities. However, one’s emotional state distorts duration perception. Some timing researchers assume that such distortion reflects processes that allow individuals to adaptively respond to changes in their environment. In recent decades, a large body of studies examined the effect of basic emotion on duration perception. However, the results were mixed. Specifically, although some studies supported that basic emotions (fear, anger, disgust, sadness, happiness) prolonged duration perception compared to neutral stimuli, there were also contradictory results. Furthermore, the results of the comparisons among basic emotions were more mixed. Thus, we conducted a three-level meta-analysis and network meta-analysis to investigate the effect of basic emotion on time perception and moderating factors.

We conducted an exhaustive literature search using sequential strategies to locate studies that provide data on the effects of basic emotion on duration perception, the last literature update was on July 12, 2024. The three-level meta-analysis was conducted using the metafor package. The procedure was as follows: we calculated the standardized mean difference (g) in duration perception between basic emotions and neutral stimuli. Then, we performed a main effect test using a three-level random-effects model, tested moderator variables using a three-level mixed-effects model, and assessed publication bias using funnel plots, two-level Egger regression, three-level Egger regression, and the trim-and-fill method. The network meta-analysis was conducted using the netmeta package. The procedure was as follows: a random-effects model was used to fit the network model, followed by ranking the duration perception of basic emotions based on p-scores and calculating the league table; finally, model inconsistency was assessed using the full design-by-treatment interaction random-effects model and node splitting method.

A total of 3504 potential literature was retrieved. After screening, 36 articles met the inclusion criteria for meta-analysis. The three-level random-effects model found that the duration perception of basic emotions was longer compared to neutral stimuli, g = 0.24, 95% CI [0.13, 0.36], p < 0.001. Moderation analysis revealed that the type of basic emotion, age group, and time task were significant moderator variables. Additionally, main effect analyses conducted for each basic emotion individually revealed that the duration perception of happiness, fear, and anger was longer than that of neutral stimuli. In the network meta-analysis, we included only studies that used the time bisection method and samples of early adulthood individuals. The results revealed that duration perception was longer for fear and anger than for sad emotions.

Combining the three-level meta-analysis and the network meta-analysis, the following conclusions were drawn: Compared to neutral stimuli, fear, and anger emotions can consistently induce prolonged duration perception; additionally, the duration perception for fear and anger is longer than for sadness. This pattern aligns with the “adaptive” perspective, supporting the notion that the prolongation of duration perception by emotions is an adaptive outcome. The more important an emotion is for “harm avoidance,” the longer the duration of perception it induces.

The spatial-numerical association of response codes (SNARC) effect demonstrates that responding to small numbers with the left key is faster than responding with the right key, while the converse is true for large numbers. A long-standing debate has been whether the SNARC effect occurs only in the early stimulus-representation stage, only in the late response-selection stage or in both stages simultaneously. The study aims to manipulate two processing stages to investigate the effects of interference with the early stimulus-representation and late response-selection on the SNARC effect.

Combining numbers with arrows by the global and local paradigm, a compound stimulus—arrows made up with numbers—was designed as experimental materials. In experiment 1a, a within-subject experimental design with 2(Number magnitude: small, large) × 3 (Arrow direction: left, right, double left and right) × 2 (Response hand: left hand, right hand) was conducted. 40 subjects were asked to judge whether the number is larger or smaller than 5. In experiment 1b, a within-subject experimental design with 2(Number magnitude: small, large) × 3 (Arrow direction: up, down, double up and down) × 2 (Response hand: left hand, right hand) was employed. 40 subjects were asked to judge whether the number is larger or smaller than 5. The experimental design in experiment 2 is as the same as the experiment 1a, however, 40 subjects were asked to judge whether the arrow is left or right.

Results showed that horizontal interference with the spatial representation of numbers hindered the emergence of the SNARC effect (Experiment 1a), however, vertical interference with the spatial representation of numbers had no influence on the SNARC effect (Experiment 1b). Interference with the response selection stage impeded the emergence of the SNARC effect (Experiment 2).

According to the global precedence theory, global representation of horizontal arrow directions interfered with the spatial representation process of local numbers, thereby the SNARC effect in experiment 1a is disappeared. According to the mental number line theory, individuals mentally represent numbers based on a left-to-right mental number line. Thus, the interference from the global representation of vertical arrow directions doesn’t influence the SNARC effect in experiment 1b. When arrows made up with numbers are used in experiment 2 requiring participants to judge arrow directions, the numbers can be automatically processed and adequately spatially represented at an unconscious level. However, due to the arrow direction judgment task consumes cognitive resources or occupies the corresponding reaction position during the response-selection stage, the SNARC effect diminishes.

In summary, both the early stimulate-representation stage and the late response-selection stage play important roles in the occurrence of SNARC effect.

Embodied cognition theories assume that conceptual representations are essentially rooted in modal experiential information. However, abstract concepts that do not refer to entities with a direct sensorimotor connection have challenged these embodied theories. For example, it is still debated whether abstract verb meanings are represented in the sensorimotor system. After screening and analyzing previous studies, the involvement of the motor system in the representations of abstract verbs is believed to be modulated by motor features. Abstract verbs that are learned in conjunction with more motor experiences are more likely to be predominant in motor features and accordingly are grounded much more strongly in the motor system. The present study aimed to explore the causal role of motor features of abstract verbs in their representations in the motor system and provide an explanation for the variance of previous results.

Forty-four participants (6 males) were recruited for Experiment 1; one male participant withdrew for private reasons, and all of his data were removed from the analysis. Experiment 1 lasted four days. On Day 1 and Day 4, pre- and postlearning tests, respectively, were conducted; in these tests, participants were instructed to perform a lexical decision task first inside a 3.0 T Siemens Prisma magnetic resonance imaging (MRI) scanner. During scanning, 240 words (including 60 target novel words) were presented in a pseudorandomized sequence within an event-related design. Then, outside the scanner, the same behavioral task with 120 words (including 60 target novel words) was performed on computers with responses collected according to the action?sentence compatibility effect paradigm. On Days 2 and 3, participants spent approximately one hour each day learning and memorizing 60 target novel words and their interpretive abstract meanings, which were printed on cards. While learning, participants were asked to perform a specific hand movement toward or away from themselves as required, with the aim of successfully increasing the predominance of motor features associated with the target novel words. The neuroimaging data acquired during the fMRI tests were preprocessed and analyzed using SPM and DPABI. At the whole-brain level, a 2 × 2 ANOVA was performed. The two within-subject factors were the testing phase (pre- vs. postlearning) and word type (learning vs. nonlearning novel words). We found that for learning novel words, compared with the prelearning test, there were stronger activations in motion-related brain areas (such as the left precentral gyrus) during the postlearning test. Furthermore, the scores for motor features associated with learning novel words significantly predicted the degree of neural activation in the motor system (i.e., the right pre- and postcentral gyri, the left precentral gyrus, etc.) in the postlearning test.

Thirty participants from Experiment 1 participated in Experiment 2. They were instructed to learn 30 novel words selected from the above 60 target words in a similar way as in Experiment 1. After approximately 30 minutes of learning, the participants performed the lexical decision task while their arm’s electromyographic activities were recorded with a wireless electromyography (EMG) measurement module from BIOPAC. The results showed that processing learning novel words with increased motor features, compared with nonlearning novel words (i.e., the baseline), elicited increased EMG activities in the right extensor digitorum muscle.

In conclusion, the present study confirmed the causal role of motor features in the embodied representations (i.e., representations in the motor system) of abstract verbs. An increase in motor features makes the representations of abstract verbs more dependent on the motor system. Moreover, the processing of abstract verbs with sufficient motor features could elicit motor resonance in the peripheral motor system. These findings provide new evidence and important interpretations for embodied cognition theories.

This study investigates the variation patterns of visual complexity effects during the process of repeated learning of new words through two experiments. Utilizing a reading paradigm accompanied by vocabulary learning, two-character pseudowords were embedded in 15 contexts and presented to participants across five times intervals. In Experiment 1, the number of strokes of new words (high vs. low) was manipulated, while Experiment 2 manipulated word length (two-character vs. three-character words), recording college students' eye movements while reading sentences. Results showed that as the frequency of new word learning increased, the number of strokes effect did not exhibit significant changes, indicating that number of strokes, as a factor reflecting the visual complexity ofChinese characters, influences both early and late stages of vocabulary learning, consistent with the visual constraint hypothesis. In contrast, as new word learning frequency increased, the word length effect gradually diminished, demonstrating a “familiarity” effect of word length, which aligns with the joint visual and linguistic constraint hypothesis. These findings suggest that the mechanisms by which number of strokes and word length operate in Chinese reading during vocabulary acquisition differ: number of strokes functions as a form of low-level visual information affecting the visual layer of vocabulary processing, whereas word length resembles a higher-level linguistic processing mechanism impacting the higher tiers of vocabulary processing.

Selective trust in preschoolers plays a crucial role in their social learning, and their ability to evaluate and form trust judgments toward individuals based on differing moral promises is essential for their moral development. Experiment 1 employed a binary choice paradigm, manipulating the moral valence of promises (moral vs. immoral) and the fulfillment of promises (kept vs. broken), to examine whether preschoolers can make different trust judgments toward different moral promisors. Results indicated that by 3.5 years of age, children began to show differentiated trust in contrasting scenarios, selectively trusting those who kept moral promises and those who broke immoral ones. This selective trust strengthened with age, suggesting a significant age effect. However, it remains unclear whether children can form trust judgments toward a promisor presented in an isolated scenario. To address this, Experiment 2 employed a single-choice paradigm to assess preschoolers’ trust in different moral promisors. Results revealed distinct trust patterns: children trusted those who kept moral promises more than those who broke immoral ones, while those who broke moral promises were trusted at similar levels to those who kept immoral promises. Together, the two experiments indicate that by 3.5 years of age, children can differentiate between the moral valence and fulfillment of promises, and they make nuanced trust judgments accordingly. These findings offer valuable insights into the development of children's moral reasoning and social learning mechanisms, with important implications for promoting moral education in early childhood.

Research on the connection between altitude and depression in China remains scarce, despite the country’s extensive plateau regions. While the impact of altitude on physical health is well documented, existing studies have largely focused on social adaptation or physical well-being, leaving the relationship between altitude and depression underexplored. This study addresses this gap by examining how altitude affects depression among Chinese residents.

Data were drawn from various sources, including the 2016?2020 China Family Panel Studies, the 2015 China Health and Retirement Longitudinal Study, the 2016 survey on physical and mental health in Yushu, and statistics from the China Urban Statistical Yearbook and China Statistical Yearbook. The study involved several statistical techniques, including multilevel linear models, mediation models, and epidemiological case-control methods. The results revealed a significant positive association between altitude and depression, even when personal factors such as age, sex, education, and chronic illness were controlled for, along with regional factors such as temperature, PM2.5 concentration, per capita GDP, and hospital bed availability. Notably, per capita GDP and C-reactive protein levels were found to mediate this relationship. The risk of depression in individuals living at altitudes of 500?1, 000 meters, 1, 000?2, 000 meters, and 4, 000?6, 000 meters was 1.53?1.79 times, 1.67?2.25 times, and 9 times greater, respectively, than the risk in for individuals living below 500 meters.

The study also revealed age-specific variations in the risk of depression. Middle-aged and elderly individuals living at altitudes between 500?2, 000 metres are more vulnerable to depression than younger individuals are. In contrast, young people residing at altitudes of 4, 000?6, 000 metres face a greater risk of depression than their older counterparts do. These findings highlight the diverse impacts of altitude on the risk of depression across different age groups.

In conclusion, this study highlights altitude as a significant risk factor affecting depression among Chinese residents, which suggests the need for targeted mental health interventions that consider both age and altitude. It also challenges the traditional view of age and mental health, suggesting that both individual and environmental factors should be considered in mental health prevention and intervention strategies.