Xiuyan Guo

Unconscious structural knowledge of form-meaning connections.

We investigated the implicit learning of a linguistically relevant variable (animacy) in a natural language context (namely, the relation of forms of determiners to semantics). Trial by trial subjective measures indicated that exposure to a form-animacy regularity led to unconscious knowledge of that regularity. Under the same conditions, people did not learn about another form-meaning regularity when a linguistically arbitrary variable was used instead of animacy (size relative to a dog). Implicit learning is constrained to acquire unconscious knowledge about features with high prior probabilities of being relevant in that domain.

Acquisition of conscious and unconscious knowledge of semantic prosody

An experiment explored the acquisition of conscious and unconscious knowledge of semantic prosody in a second language under incidental and intentional learning conditions. Semantic prosody is the conotational coloring of the semantics of a word, largely uncaptured by dictionary definitions. Contrary to some claims in the literature, we revealed that both conscious and unconscious knowledge were involved in the acquisition of semantic prosody. Intentional learning resulted in similar unconscious but more conscious knowledge than incidental learning. The results are discussed in terms of second language learning and the nature of unconscious knowledge.

Unconscious structural knowledge of tonal symmetry: Tang poetry redefines limits of implicit learning

The study aims to help characterize the sort of structures about which people can acquire unconscious knowledge. It is already well established that people can implicitly learn n-grams (chunks) and also repetition patterns. We explore the acquisition of unconscious structural knowledge of symmetry. Chinese Tang poetry uses a specific sort of mirror symmetry, an inversion rule with respect to the tones of characters in successive lines of verse. We show, using artificial poetry to control both n-gram structure and repetition patterns, that people can implicitly learn to discriminate inversions from non-inversions, presenting a challenge to existing models of implicit learning.

Neural responses to unfairness and fairness depend on self-contribution to the income

Self-contribution to the income (individual achievement) was an important factor which needs to be taken into individuals fairness considerations. This study aimed at elucidating the modulation of self-contribution to the income, on recipients responses to unfairness in the Ultimatum Game. Eighteen participants were scanned while they were playing an adapted version of the Ultimatum Game as responders. Before splitting money, the proposer and the participant (responder) played the ball-guessing game. The responders contribution to the income was manipulated by both the participants and the proposers accuracy in the ball-guessing game. It turned out that the participants more often rejected unfair offers and gave lower fairness ratings when they played a more important part in the earnings. At the neural level, anterior insula, anterior cingulate cortex, dorsolateral prefrontal cortex and temporoparietal junction showed greater activities to unfairness when self-contribution increased, whereas ventral striatum and medial orbitofrontal gyrus showed higher activations to fair (vs unfair) offers in the other-contributed condition relative to the other two. Besides, the activations of right dorsolateral prefrontal cortex during unfair offers showed positive correlation with rejection rates in the self-contributed condition. These findings shed light on the significance of self-contribution in fairness-related social decision-making processes.

Hippocampal activity is associated with self-descriptiveness effect in memory, whereas self-reference effect in memory depends on medial prefrontal activity.

The self has long been regarded as a unique cognitive structure by virtue of its superior mnemonic abilities. Two separate effects result from this self memory facilitation: self‐reference effect and self‐descriptiveness effect in memory. Self‐reference effect denotes that information processed with reference to the self is better remembered than information processed with reference to others, whereas self‐descriptiveness effect indicates that items judged to be self‐relevant is remembered better than items judged not to be relevant to self during self‐reference task. Although there is a compelling connection between self‐reference effect in memory and self mentalization processes indexed by the medial prefrontal activity, the underlying mechanisms of the self‐descriptiveness effect in memory have remained underspecified. In the present fMRI study, we used a subsequent memory paradigm to examine the neural correlates of self‐descriptiveness and self‐reference effect in memory. Participants encoded personality traits while performing self‐reference and other‐reference task (judged the descriptiveness of the traits to themselves or a famous person “Bruce Lee”), and then were given a test of recognition memory outside the scanner. It is revealed that the hippocampal activity corresponded with self‐descriptiveness effect in memory, but the activity of the medial prefrontal cortex and perirhinal cortex related to self‐reference effect in memory. These findings suggested that the memory boost for self‐relevant items relies on the enhanced relational binding mechanisms employed during self‐relevant items.

Exposure to violence reduces empathetic responses to other’s pain

Past researches showed that empathy for pain not only triggers a resonance mechanism between other and self, but also is modulated by contextual factors. Using functional magnetic resonance imaging, the present study demonstrated that short-term media violence exposure reduced both pain ratings and also the activation of anterior insula and anterior mid-cingulate cortex to others pain. Thus, violence exposure modulated empathic responses to others pain based on a physiological desensitization.

The nature of the memory buffer in implicit learning: learning Chinese tonal symmetries.

Previous research has established that people can implicitly learn chunks, which (in terms of formal language theory) do not require a memory buffer to process. The present study explores the implicit learning of nonlocal dependencies generated by higher than finite-state grammars, specifically, Chinese tonal retrogrades (i.e. centre embeddings generated from a context-free grammar) and inversions (i.e. cross-serial dependencies generated from a mildly context-sensitive grammar), which do require buffers (for example, last in-first out and first in-first out, respectively). People were asked to listen to and memorize artificial poetry instantiating one of the two grammars; after this training phase, people were informed of the existence of rules and asked to classify new poems, while providing attributions of the basis of their judgments. People acquired unconscious structural knowledge of both tonal retrogrades and inversions. Moreover, inversions were implicitly learnt more easily than retrogrades constraining the nature of the memory buffer in computational models of implicit learning.

Implicit Learning and Recursion

Implicit learning research has focused on learning simple structures, such as chunks, even though such structures do not capture the richness of real-world human accomplishments. In particular, music and language exhibit certain recursive features that cannot be captured by regular grammars, let alone mechanisms that learn only chunks. We show in the domains of music, language, poetry and movement that people can implicitly learn recursive grammars in ways that go beyond learning chunks or mere repetition patterns. This is supported by the fact that participants are found to generalise from training materials to novel sequences following the underlying rules. In this context we further propose a parsimony argument that states that although performance on new test items can always be explained by a catch-all finite-state or chunking mechanism, such explanations can be more complex than postulating learning a supra-finite-state mechanism in that they may postulate considerably more rules or states than necessary to explain learning. This is especially true when the finite-state rather than supra-finite-state mechanism, in order to perform on the test material, needs to acquire states or chunks not required for learning the training material. We highlight both the strength and weakness of our current evidence in this regard.

Bidirectional Transfer between Metaphorical Related Domains in Implicit Learning of Form-Meaning Connections

People can implicitly learn a connection between linguistic forms and meanings, for example between specific determiners (e.g. this, that…) and the type of nouns to which they apply. Li et al (2013) recently found that transfer of form-meaning connections from a concrete domain (height) to an abstract domain (power) was achieved in a metaphor-consistent way without awareness, showing that unconscious knowledge can be abstract and flexibly deployed. The current study aims to determine whether people transfer knowledge of form-meaning connections not only from a concrete domain to an abstract one, but also vice versa, consistent with metaphor representation being bi-directional. With a similar paradigm as used by Li et al, participants learnt form- meaning connections of different domains (concrete vs. abstract) and then were tested on two kinds of generalizations (same and different domain generalization). As predicted, transfer of form-meaning connections occurred bidirectionally when structural knowledge was unconscious. Moreover, the present study also revealed that more transfer occurred between metaphorically related domains when judgment knowledge was conscious (intuition) rather than unconscious (guess). Conscious and unconscious judgment knowledge may have different functional properties.

Fluency Expresses Implicit Knowledge of Tonal Symmetry.

The purposes of the present study were twofold. First, we sought to establish whether tonal symmetry produces processing fluency. Second, we sought to explore whether symmetry and chunk strength express themselves differently in fluency, as an indication of different mechanisms being involved for sub- and supra-finite state processing. Across two experiments, participants were asked to listen to and memorize artificial poetry showing a mirror symmetry (an inversion, i.e., a type of cross serial dependency); after this training phase, people completed a four-choice RT task in which they were presented with new artificial poetry. Participants were required to identify the stimulus displayed. We found that symmetry sped up responding to the second half of strings, indicating a fluency effect. Furthermore, there was a dissociation between fluency effects arising from symmetry vs. chunk strength, with stronger fluency effects for symmetry rather than chunks in the second half of strings. Taken together, we conjecture a divide between finite state and supra-finite state mechanisms in learning grammatical sequences.