Widespread PREMA in the upper mantle indicated by low-degree basaltic melts.

Studies of ocean island basalts have identified a Prevalent Mantle (PREMA) component as a fundamental feature of mantle geochemical arrays; however, its origin and distribution are highly controversial, including its potential link to plumes sourced in low-shear-wave velocity provinces (LLSVPs) above the core-mantle boundary. In this study, we interrogate the compositional systematics of ~ 3500 Cenozoic oceanic and continental sodic basalts to provide insights into the origin and distribution of PREMA. We find that low-degree basaltic melts with high Nb concentrations located away from deep-mantle plumes have PREMA-like Sr-Nd-Hf isotopic signatures, implying that PREMA is highly fusible and not exclusively associated with LLSVPs. Geochemical modelling and mantle convection simulations indicate that PREMA could have been generated soon after Earth accretion, experiencing only minimal melting or enrichment, and then scattered throughout the upper mantle, rather than being the result of mixing between depleted and enriched mantle components.

The Effect of Negative Feedback on Positive Beliefs in Self-Deception.

In the present study, we applied the forward-looking paradigm to examine how positive beliefs appear in self-deception and to further reveal the influence of negative feedback on positive beliefs to decrease self-deception. In Experiment 1, the answer group (with answer hints provided below the test material) and the control group (without answer hints) completed two tests. Participants estimated their Test 1 scores, predicted their performance on the upcoming Test 2 without answer hints, and completed Test 2. Their actual scores on the two tests were recorded. The results showed that the answer group predicted higher Test 2 scores than the control group, but the two groups did not differ in their actual scores. These results showed that the answer group had positive self-deception. In Experiment 2, the two groups were given negative feedback (vs. no feedback) after Test 1, and the changes between their estimated scores on Test 1 and their predicted score and actual score on Test 2 were measured. The results indicated that there was no significant difference in the estimated scores and the predicted score between the two groups under the feedback condition compared with the negative feedback condition. These findings demonstrated that the effectiveness of the forward-looking paradigm can activate participants' positive beliefs and cheat behaviors by providing the answers to induce self-deception, and negative feedback can decrease the occurrence of self-deception by reducing the positive beliefs of individuals and improving self-awareness to prevent or eliminate the negative impact of self-deception.

Negative Emotion Weakens the Degree of Self-Reference Effect: Evidence from ERPs.

We investigated the influence of negative emotion on the degree of self-reference effect using event-related potentials (ERPs). We presented emotional pictures and self-referential stimuli (stimuli that accelerate and improve processing and improve memory of information related to an individual's self-concept) in sequence. Participants judged the color of the target stimulus (self-referential stimuli). ERP results showed that the target stimuli elicited larger P2 amplitudes under neutral conditions than under negative emotional conditions. Under neutral conditions, N2 amplitudes for highly self-relevant names (target stimulus) were smaller than those for any other names. Under negative emotional conditions, highly and moderately self-referential stimuli activated smaller N2 amplitudes. P3 amplitudes activated by self-referential processing under negative emotional conditions were smaller than neutral conditions. In the left and central sites, highly self-relevant names activated larger P3 amplitudes than any other names. But in the central sites, moderately self-relevant names activated larger P3 amplitudes than non-self-relevant names. The findings indicate that negative emotional processing could weaken the degree of self-reference effect.

Electrophysiological correlation of the degree of self-reference effect.

The present study investigated neural correlations underlying the psychological processing of stimuli with various degrees of self-relevance. Event-related potentials were recorded for names that differ in their extent of relevance to the study participant. Participants performed a three-stimulus oddball task. ERP results showed larger P2 averaged amplitudes for highly self-relevant names than for moderately self-relevant, minimally self-relevant, and non-self-relevant names. N2 averaged amplitudes were larger for the highly self-relevant names than for the moderately self-relevant, minimally self-relevant, and non-self-relevant names. Highly self-relevant names elicited larger P3 averaged amplitudes than the moderately self-relevant names which, in turn, had larger P3 values than for minimally self-relevant names. Minimally self-relevant stimuli elicited larger P3 averaged amplitudes than non-self-relevant stimuli. These results demonstrate a degree effect of self-reference, which was indexed using electrophysiological activity.