Liang Meng

Evolutions of structure, composition and optical absorption behavior of pyrite films formed by sulfurating iron

The crystal structure, crystallite morphology, film composition and absorption properties were investigated for the pyrite films sulfurated from iron films. The pyrite particles nucleate mainly from the transitional phases of iron sulfides formed in the films during 673 K sulfurating while the pyrite particles nucleate directly from the iron bisulfides formed in the films during 773 K sulfurating. There are higher sulfur contents and more obvious grain propagation in the film sulfurated at 773 K than in that sulfurated at 673 K. By prolonging sulfuration time at 673 K, the optical absorption edge tends to increase and approaches the ideal value as sulfurated over 20 h. Low absorption edges exist in the films sulfurated at 773 K.

The undermining effect of facial attractiveness on brain responses to fairness in the Ultimatum Game: an ERP study

To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as “attractive” and “unattractive”) were presented prior to the offer presentation. The behavioral data demonstrated that the acceptance ratio increased with the fairness level of the offers and, more importantly, the subjects were more likely to accept unfair offers when presented with the attractive-face condition compared with the unattractive-face condition. The reaction times (RTs) for five offers (1:9, 2:8, 3:7, 4:6, and 5:5) in the unattractive-face condition were not significantly different. In contrast, the subjects reacted slower to the attractive proposers unfair offers and quicker to fair offers. The ERP analysis of the face presentation demonstrated a decreased early negativity (N2) and enhanced late positive potentials (LPPs) elicited by the attractive faces compared with the unattractive faces. In addition, the feedback-related negativity (FRN) in response to an offer presentation was not significantly different for the unfair (1:9 and 2:8) and fair (4:6 and 5:5) offers in the attractive-face condition. However, the unfair offers generated larger FRNs compared with the fair offers in the unattractive-face condition (consistent with prior studies). A similar effect was identified for P300. The present study demonstrated an undermining effect of proposer facial attractiveness on responder consideration of offer fairness during the UG.

I endeavor to make it: Effort increases valuation of subsequent monetary reward

Although it is commonly accepted that the amount of effort we put into accomplishing a task would exert an influence on subsequent reward processing and outcome evaluation, whether effort is incorporated as a cost or it would increase the valuation of concomitant reward is still under debate. In this study, EEGs were recorded while subjects performed calculation tasks that required different amount of effort, correct responses of which were followed by either no reward or fixed compensation. Results showed that high effort induced larger differentiated FRN responses to the reward and non-reward discrepancy across two experimental conditions. Furthermore, P300 manifested valence effect during reward feedback, with more positive amplitudes for reward than for non-reward only in the high effort condition. These results suggest that effort might increase subjective evaluation toward subsequent reward.

Live as we choose: The role of autonomy support in facilitating intrinsic motivation

According to Self-determination Theory (SDT), autonomy is a basic psychological need, satisfaction of which may lead to enhanced intrinsic motivation and related beneficial outcomes. By manipulating the opportunity to choose between tasks of equal difficulty, throughout the motivational process, the effect of autonomy support was examined both behaviorally and electrophysiologically. More negative stimulus-preceding negativity (SPN) and an enlarged FRN loss-win difference wave (d-FRN) indicated an enhanced expectation toward the positive outcome (during the anticipation stage) as well as intensified intrinsic motivation toward the task (during the outcome appraisal stage) when choice was available. Taken together, results of the present study suggest d-FRN upon feedback as a real-time electrophysiological indicator of intrinsic/autonomous motivation and illustrate the important role of autonomy-supportive job design in the workplace.

You Have My Word: Reciprocity Expectation Modulates Feedback-Related Negativity in the Trust Game

Promise is one of the most powerful tools producing trust and facilitating cooperation, and sticking to the promise is deemed as a key social norm in social interactions. The present study explored the extent to which promise would influence investors’ decision-making in the trust game where promise had no predictive value regarding trustees’ reciprocation. In addition, we examined the neural underpinnings of the investors’ outcome processing related to the trustees’ promise keeping and promise breaking. Consistent with our hypothesis, behavioral results indicated that promise could effectively increase the investment frequency of investors. Electrophysiological results showed that, promise induced larger differentiated-FRN responses to the reward and non-reward discrepancy. Taken together, these results suggested that promise would promote cooperative behavior, while breach of promise would be regarded as a violation of the social norm, corroborating the vital role of non-enforceable commitment in social decision making.

Diffusion annealing of copper–silver bimetallic strips at different temperatures

Abstract Copper–silver bimetallic strips prepared by cold roll cladding have been treated by diffusion annealing in the temperature range 250–800 °C. The interface bonding level and the hardness of the matrix copper and silver have been determined and the microstructure in the interface region has been observed. The interface bonding level is particularly enhanced by annealing at 400 and 800 °C. High diffusion anneal temperatures lead to reductions in the strip hardness values. Recrystallization could just be detected in the strips annealed at 250 °C but were much more manifest at 400 °C. Annealing above 600 °C produces fine-grained areas between the interface and the silver matrix. Diffusion anneal treatments that can induce recovery, recrystallization, or partial fusion at the bonding interface can lead to enhancement of the interface bonding level.

How do social-based cues influence consumers' online purchase decisions? An event-related potential study

Product rating and sales are two important social-based cues in online shopping. This study applies the event-related potential (ERP) approach to explore the underlying neural mechanism of the joint influence of these two cues on consumers’ decision-making. Behavioral data show that product rating has a greater impact on the purchasing rate than sales, which positively moderates the latter’s effect and supports cue-diagnosticity theory. Electrophysiological data provide further explanations for the observed behavioral pattern. Analyses of main ERP components suggest that consumers go through a series of cognitive processes from processing of perceived risk (N2) and informational conflict (N400) to evaluative categorization (LPP) before making the final purchasing decision. Specifically, product rating significantly influences the risk perception while the combination of high rating and low sales elicits significant cognitive conflict. Both cues are adopted by consumers to make an overall evaluation based on their similarity to the criterion.

You did not mean it: Perceived good intentions alleviate sense of unfairness

Previous research has reported that feedback-related negativity (FRN) may represent the degree of perceived unfairness in the ultimatum game (UG). However, few studies have incorporated intention-related consideration in examining the neural correlates of fairness perception. To address this issue, the present study introduced an intentional UG paradigm to disentangle the effect of perceived intention from fairness concerns, using an event-related potential (ERP) analysis. Consistent with the hypothesis, the behavioral results indicated that good intention could markedly reduce rejection rates, and this intention effect was modulated by the degree of fairness, which was more prominent under unfair scenarios. Further electrophysiological results showed that, for the unfair division schemes, FRN and P300 amplitudes were significantly different between offers proposed with good intention and those with bad intention, while such discrepancies were not observed for the fair condition. In summary, converging results demonstrated that perceived intention can modulate the effect of fairness in social decision-making.

Close games versus blowouts: Optimal challenge reinforces one's intrinsic motivation to win

When immersed in intrinsically motivating activities, individuals actively seek optimal challenge, which generally brings the most satisfaction as they play hard and finally win. To better simulate real-life scenarios in the controlled laboratory setting, a two-player online StopWatch (SW) game was developed, whose format is similar to that of a badminton tournament. During the game, a male opponent played by a confederate ensured that the same-sex participant paired with him won both matches, one with a wide margin (the lack of challenge condition) and another with a narrow one (the optimal challenge condition). Electrophysiological data were recorded during the entire experiment. An enlarged Stimulus-preceding negativity (SPN) was observed in the optimal challenge condition, indicating a more concentrated anticipatory attention toward the feedback and a stronger intrinsic motivation during close games. Thus, this study provided original neural evidence for predictions of Self-determination theory (SDT) and Flow theory, and confirmed and emphasized the significant role of optimal challenge in promoting ones intrinsic motivation to win.

Inverted U-Shaped Curvilinear Relationship between Challenge and One's Intrinsic Motivation: Evidence from Event-Related Potentials

The balance between task demand and ones competence is critical for the maintenance of intrinsic motivation. According to Flow theory and Self-determination theory, optimal challenge gives rise to the maximum intrinsic motivation, and an inverted U-shaped curvilinear relationship between perceived challenge and ones intrinsic motivation is suggested. In order to provide direct experimental evidences for predictions of these theories, in this study, we employed the two-player StopWatch game that we previously designed, which made references to the game format of a badminton tournament. According to our manipulation, a male participant was defeated by the same-sex player paired with him (played by a well-trained confederate of the experimenter) in two matches, one with a wide margin (the complete defeat condition) and another with a narrow one (the near miss condition). Participants performed better and reported to enjoy the near miss match to a greater extent. Besides, an enlarged Stimulus-preceding negativity was elicited when participants were actively anticipating outcomes in the near miss condition, suggesting greater anticipatory attention toward the outcome and an enhanced intrinsic motivation to win. Thus, converging electrophysiological evidences from this study and our former study confirmed the inverted U-shaped curvilinear relationship between perceived challenge and ones intrinsic motivation.