The role of gamma band oscillations and synchrony on rubber hand illusion and crossmodal integration

The rubber hand illusion represents an illusory experience during the mislocalization of own hand when correlated visuotactile stimuli are presented to the actual and fake hands. The visuotactile integration process appears to cause this illusion; the corresponding brain activity was revealed in many studies. In this study, we investigated the effect of the rubber hand illusion on the crossmodal integration process by measuring EEG. The participants who experienced less intensive illusion showed greater congruency effect on reaction time (RT), greater power increase at the parietal zero electrode (Pz) and smaller interelectrode synchrony of the gamma band activity. On the other hand, the participants who experienced more intense illusion showed greater interelectrode synchrony. The results suggested that the gamma band activity in the parietal area reflects the visuotactile integration process and that its synchrony causes the illusory intensity.     

Development of the Brief Personal Values Inventory for Sense of Values

The Portrait Values Questionnaire (PVQ) is a widely used questionnaire for assessing sense of values; however, it is difficult to apply for children and adolescents. Therefore, the present study aimed to develop a questionnaire for sense of values, called the Brief Personal Values Inventory (BPVI), consisting of simple questions and fewer items compared to the PVQ. We first created 12 items for the BPVI and then tested criterion-related validity with values in the PVQ-57 in 167 Japanese general population participants (81 males, mean age [SD], range: 23.4 [8.2], 15–57 years). Each of these items was correlated with one or more of the values in the PVQ-57 and covered all higher-order values in Schwartz's theory (openness to change, self-enhancement, conservation, and self-transcendence). In summary, the BPVI adequately corresponded with Schwartz's value theory, indicating an acceptable criterion-related validity. This questionnaire is applicable to a wide population, including adolescents, and will be a useful tool for researchers to elucidate the developmental pathway of personal sense of values.     

Force Control of Ankle Dorsiflexors in Young Adults: Effects of Bilateral Control and Leg Dominance

Abstract

We investigated whether bilateral lower-limb control and leg dominance affect force control ability in 15 healthy young adults (9 males and 6 females, age =26.8?±?4.1 years). Participants performed isometric ankle dorsiflexion force control tasks, matching a visual target (10% of maximal effort) as quickly and precisely as possible in ballistic and tonic tasks. Performance was evaluated using force error, force steadiness, amount of muscle activity of the tibialis anterior, and response time characteristics. Results showed no significant effects of leg dominance during both ballistic and tonic tasks, while bilateral condition resulted in significantly larger error, less force steadiness, compared to unilateral condition, and only during the tonic task. Consequently, bilateral control, specifically in tasks utilizing feedback control (i.e., tonic task) might affect force control ability, possibly because of the interhemispheric inhibition to meet bilateral task complexity and integrate afferent bilateral sensory information from both right and left legs.     

Automated gaze-contingent objects elicit orientation following in 8-month-old infants

The current study tested whether the purely amodal cue of contingency elicits orientation following behavior in 8-month-old infants. We presented 8-month-old infants with automated objects without human features that did or did not react contingently to the infants' fixations recorded by an eye tracker. We found that an object's occasional orientation toward peripheral targets was reciprocated by a congruent visual orientation following response by infants only when it had displayed gaze-contingent interactivity. Our finding demonstrates that infants' gaze-following behavior does not depend on the presence of a human being. The results are consistent with the idea that, in 8-month-old infants, the detection of contingent reactivity, like other communicative signals, can itself elicit the illusion of being addressed.     

Does perceived direct gaze boost detection in adults and children with and without autism? The stare-in-the-crowd effect revisited

This study extended that of von Grünau and Anston (1995) and explored whether perceived direct gaze is easily detected by individuals with and without autism, utilizing a visual-search paradigm. Participants detected target faces with either direct gaze or averted gaze. Laterally averted faces were used to eliminate the involvement of lower perceptual characteristics such as symmetry, which were inherent with the “straight gaze” used by von Grünau and Anston. Both typically developed adults and children detected targets with direct gaze more quickly than those with averted gaze, but face inversion distorted this asymmetrical performance, suggesting the contribution of configurative facial processing. In contrast, children with autism were not affected by the gaze direction presented by realistic facial stimuli. They were, however, faster to detect straight gaze defined solely by local features, which suggests that their impairment might be specific to the detection of direct gaze presented within a facial context.     

Illusion of sense of self-agency: discrepancy between the predicted and actual sensory consequences of actions modulates the sense of self-agency, but not the sense of self-ownership

It is proposed that knowledge of motor commands is used to distinguish self-generated sensation from externally generated sensation. In this paper, we show that the sense of self-agency, that is the sense that I am the one who is generating an action, largely depends on the degree of discrepancy resulting from comparison between the predicted and actual sensory feedback. In Experiment 1, the sense of self-agency was reduced when the presentation of the tone was unpredictable in terms of timing and its frequency, although in fact the tone was self-produced. In Experiment 2, the opposite case was found to occur. That is, participants experienced illusionary sense of self-agency when the externally generated sensations happened to match the prediction made by forward model. In Experiment 3, the sense of self-agency was reduced when there was a discrepancy between the predicted and actual sensory consequences, regardless of presence or absence of a discrepancy between the intended and actual consequences of actions. In all the experiments, a discrepancy between the predicted and actual feedback had no effects on sense of self-ownership, that is the sense that I am the one who is undergoing an experience. These results may suggest that both senses of self are mutually independent.     

Understanding the referential nature of looking: infants' preference for object-directed gaze

In four experiments, we investigated whether 9-month-old infants are sensitive to the relationship between gaze direction and object location and whether this sensitivity depends on the presence of communicative cues like eye contact. Infants observed a face, which repeatedly shifted its eyes either toward, or away from, unpredictably appearing objects. We found that they looked longer at the face when the gaze shifts were congruent with the location of the object. A second experiment ruled out that this effect was simply due to spatial congruency, while a third and a fourth experiment revealed that a preceding period of eye contact is required to elicit the gaze-object congruency effect. These results indicate that infants at this age can encode eye direction in referential terms in the presence of communication cues and are biased to attend to scenes with object-directed gaze.     

Dichotomous Thinking and Personality Traits: From the Viewpoints of the Big Five and HEXACO1,2

Dichotomous thinking is a feature of certain personality traits, such as the Dark Triad and Cluster B personality disorders, which commonly reflect a fast life history strategy. The Big Five and HEXACO personality models are useful for understanding the personality structure and individual differences in life history strategy. Our study aimed to shed light on the propensity for dichotomous thinking using the framework of the Big Five and HEXACO personality models. Participants (n = 229) completed the Dichotomous Thinking Inventory, the 60-item HEXACO Personality Inventory – Revised, and the Ten-Item Personality Inventory. We examined correlations between dichotomous thinking and each domain of the Big Five and HEXACO personality models, and then computed multiple correlations predicting total and dimensional scores on the propensity for dichotomous thinking with scores on the Big Five and HEXACO personality traits. Results indicated that dichotomous thinking tendency is characterized by the set of low Agreeableness and Honesty–Humility. This study suggests that dichotomous thinking has antagonistic characteristics and a linkage to the fast life history strategy.     

Dissociative experience and mood-dependent memory

Amnesia is the main phenomenon in dissociative experiences. The present study investigated whether amnesia in participants with frequent dissociative experiences depended on state-dependent memory. Undergraduates scoring high (n=32) or low (n=32) on the Dissociative Experiences Scale Version-II (DES-II) participated in this experiment. Mood induction and a remember/know task were used in a typical mood-independent memory design. In the inconsistent mood state condition, participants in the high DES group showed decreased memory performance compared to the low DES group. These results were attributed to the recollection components of recognition and not to the familiarity component. Therefore we concluded that the normal population with highly frequent dissociative experiences showed strong state-dependent memory and had a memory bias in the recollection component of memory.     

Angle illusion in a straight road

We report a new angle illusion observed when viewing a real scene involving a straight road. The scene portrays two white lines which outline a traffic lane on a road and converge to a vanishing point. In experiment 1, observers estimated the angle created by these converging lines in this scene or in its image projected onto a screen. Results showed strong underestimation of the angle, ie over 50% for observations of both the real scene and its projected image. Experiment 2 assessed how depth cues in projected images influence the angle illusion. Results showed that this angle illusion disappeared when scene information surrounding convergent lines was removed. In addition, the illusion was attenuated with projection of an inverted scene image. These findings are interpreted in terms of a misadoption of depth information in the processing of angle perception in a flat image; in turn, this induces a massive angle illusion.