An Electrocortical Measure Associated With Metarepresentation Mediates the Relationship Between Autism Symptoms and Theory of Mind

Impairments in theory of mind (ToM)—long considered common among individuals with autism spectrum disorder (ASD)—are in fact highly heterogeneous across this population. Although such heterogeneity should be reflected in differential recruitment of neural mechanisms during ToM reasoning, no research has yet uncovered a mechanism that explains these individual differences. In this study, 78 (48 with ASD) adolescents viewed ToM vignettes and made mental-state inferences about characters’ behavior while participant electrophysiology was concurrently recorded. Two candidate event-related-potentials (ERPs)—the late positive complex (LPC) and the late slow wave (LSW)—were successfully elicited. LPC scores correlated positively with ToM accuracy and negatively with ASD symptom severity. Note that the LPC partially mediated the relationship between ASD symptoms and ToM accuracy, which suggests that this ERP component, thought to represent cognitive metarepresentation, may help explain differences in ToM performance in some individuals with ASD.

Does Travel Really Enhance Destination-Country Image? Understanding Tourists’ Changes in Perception toward a Destination Country

Tourism has played a fundamental role in shaping the image of destination countries. This study aimed to examine changes in international tourists’ enhanced and complex destination-country images (DCIs) by comparing pre- and post-trip perceptions. A total of 268 and 275 valid questionnaires from pre- and post-trip Chinese outbound tourists to South Korea, respectively, were collected. The results indicated that tourists’ DCIs were dynamic and could be effectively promoted through their actual tourism experiences. Overall, when considering enhanced DCI perception, compared with pre-trip tourists, post-trip tourists possessed a positive complex DCI perception. Tourism could provide an important channel for promoting a destination country’s image to the world.

RC-positive metrics on rationally connected manifolds

In this paper, we prove that if a compact Kähler manifold X has a smooth Hermitian metric $\omega $ such that $(T_X,\omega )$ is uniformly RC-positive, then X is projective and rationally connected. Conversely, we show that, if a projective manifold X is rationally connected, then there exists a uniformly RC-positive complex Finsler metric on $T_X$ .

Forests of complex numbers

The Calkin–Wilf tree is an infinite binary tree whose vertices are the positive rational numbers. Each number occurs in the tree exactly once and in the form [Formula: see text], where [Formula: see text] and [Formula: see text] are relatively prime positive integers. In this paper, certain subsemigroups of the modular group are used to construct similar trees in the set [Formula: see text] of positive complex numbers. Associated to each subsemigroup is a forest of trees that partitions [Formula: see text]. The fundamental domain and the set of cusps of the subsemigroup are defined and computed.

Orphans in Forests of Linear Fractional Transformations

A positive linear fractional transformation (PLFT) is a function of the form $f(z)=\frac{az+b}{cz+d}$ where $a,b,c$ and $d$ are nonnegative integers with determinant $ad-bc\neq 0$. Nathanson generalized the notion of the Calkin-Wilf tree to PLFTs and used it to partition the set of PLFTs into an infinite forest of rooted trees. The roots of these PLFT Calkin-Wilf trees are called orphans. In this paper, we provide a combinatorial formula for the number of orphans with fixed determinant $D$. In addition, we derive a method for determining the orphan ancestor of a given PLFT. Lastly, taking $z$ to be a complex number, we show that every positive complex number has finitely many ancestors in the forest of complex $(u,v)$-Calkin-Wilf trees.

From Positivity to Negativity Bias: Ambiguity Affects the Neurophysiological Signatures of Feedback Processing

Previous studies on the neurophysiological underpinnings of feedback processing almost exclusively used low-ambiguity feedback, which does not fully address the diversity of situations in everyday life. We therefore used a pseudo trial-and-error learning task to investigate ERPs of low- versus high-ambiguity feedback. Twenty-eight participants tried to deduce the rule governing visual feedback to their button presses in response to visual stimuli. In the blocked condition, the same two feedback words were presented across several consecutive trials, whereas in the random condition feedback was randomly drawn on each trial from sets of five positive and five negative words. The feedback-related negativity (FRN-D), a frontocentral ERP difference between negative and positive feedback, was significantly larger in the blocked condition, whereas the centroparietal late positive complex indicating controlled attention was enhanced for negative feedback irrespective of condition. Moreover, FRN-D in the blocked condition was due to increased reward positivity (Rew-P) for positive feedback, rather than increased (raw) FRN for negative feedback. Our findings strongly support recent lines of evidence that the FRN-D, one of the most widely studied signatures of reinforcement learning in the human brain, critically depends on feedback discriminability and is primarily driven by the Rew-P. A novel finding concerned larger frontocentral P2 for negative feedback in the random but not the blocked condition. Although Rew-P points to a positivity bias in feedback processing under conditions of low feedback ambiguity, P2 suggests a specific adaptation of information processing in case of highly ambiguous feedback, involving an early negativity bias. Generalizability of the P2 findings was demonstrated in a second experiment using explicit valence categorization of highly emotional positive and negative adjectives.