A Map of Common Knowledge Logics

In order to capture the concept of common knowledge, various extensions of multi-modal epistemic logics, such as fixed-point ones and infinitary ones, have been proposed. Although we have now a good list of such proposed extensions, the relationships among them are still unclear. The purpose of this paper is to draw a map showing the relationships among them. In the propositional case, these extensions turn out to be all Kripke complete and can be comparable in a meaningful manner. F. Wolter showed that the predicate extension of the Halpern-Moses fixed-point type common knowledge logic is Kripke incomplete. However, if we go further to an infinitary extension, Kripke completeness would be recovered. Thus there is some gap in the predicate case. In drawing the map, we focus on what is happening around the gap in the predicate case. The map enables us to better understand the common knowledge logics as a whole.     

Roots of smile: a preterm neonates' study

Twenty-two preterm neonates were observed 1 h per neonate in the NICU. Ninety-five spontaneous smiles were recorded. Younger and smaller neonates showed more and longer spontaneous smiles than older and larger. The youngest neonate was 200 days from conception on the observational day. She was 511 g. This infant showed spontaneous smiles. The roots of spontaneous smiles are discussed.     

Spontaneous smile and spontaneous laugh: an intensive longitudinal case study

One male infant was observed from the day of his birth to the end of the 6th month. Total observation days were 171 days, and total observation time was 329 h 25 min and 35s. Five hundred and sixty-five spontaneous smiles and 15 spontaneous laughs (smiles accompanied by vocal sounds) were observed. Developmental psychologists have thought that spontaneous smiles integrate at about 3 months, but spontaneous smiles were recorded even in the 6th month. The percentage of bilateral smiles increased from the 2nd month. This is the first intensive longitudinal study on spontaneous smiles and spontaneous laughs.     

Response differentiation to facial expression of emotion as increasing exposure duration

This study investigated whether the underlying structure of responses to facial expressions of emotion would emerge when the exposure time was increased. 25 participants judged facial photographs presented for varying durations of exposure, ranging from 4 msec. to 64 msec. in 4-msec. steps. A dual scaling method was carried out to analyze possible response differentiation as a function of exposure time. Two major components were extracted. Based on the configuration of variables they were interpreted as valence (hedonic tone) and activation. Results indicated that a positive emotion and a highly activated emotion such as surprise and fear were easily recognized under a relatively brief exposure to the stimuli.     

Tobacco and alcohol tax relationships with suicide in Switzerland

Previous research has shown an empirical link between tobacco and alcohol use and suicide. If tobacco and alcohol use contribute to suicidal behaviors, then policies designed to reduce the tobacco and alcohol consumption may succeed in reducing suicides as well. To test this hypothesis, correlations for suicide rates with alcohol consumption, taxes on alcohol and tobacco in Switzerland were examined using sets of time-series data from Switzerland in 1965-1994. The tax on tobacco correlated significantly negatively with male standardized suicide rate. The tax on alcohol also correlated significantly with male standardized suicide rate in an autoregressive model. On the other hand, significant relationships with female suicide rate were not found. Policies designed to reduce tobacco consumption are consistent with a benefit of reducing suicides, particularly for men in this sample.     

Temporal expectation weights visual signals over auditory signals

Temporal expectation is a process by which people use temporally structured sensory information to explicitly or implicitly predict the onset and/or the duration of future events. Because timing plays a critical role in crossmodal interactions, we investigated how temporal expectation influenced auditory–visual interaction, using an auditory–visual crossmodal congruity effect as a measure of crossmodal interaction. For auditory identification, an incongruent visual stimulus produced stronger interference when the crossmodal stimulus was presented with an expected rather than an unexpected timing. In contrast, for visual identification, an incongruent auditory stimulus produced weaker interference when the crossmodal stimulus was presented with an expected rather than an unexpected timing. The fact that temporal expectation made visual distractors more potent and visual targets less susceptible to auditory interference suggests that temporal expectation increases the perceptual weight of visual signals.     

Is there any "free" choice? Self and dissonance in two cultures

Four experiments provided support for the hypothesis that upon making a choice, individuals justify their choice in order to eliminate doubts about culturally sanctioned aspects of the self, namely, competence and efficacy in North America and positive appraisal by other people in Japan. Japanese participants justified their choice (by increasing liking for chosen items and decreasing liking for rejected items) in the standard free-choice dissonance paradigm only when self-relevant others were primed, either by questionnaires (Studies 1-3) or by incidental exposure to schematic faces (Study 4). In the absence of these social cues, Japanese participants showed no dissonance effect. In contrast, European Americans justified their choices regardless of the social-cue manipulations. Implications for cognitive dissonance theory are discussed.     

Event-related brain potential in responses to social messages via human faces

In two experiments participants were presented a sequence of facial photographs to examine effects of pleasantness of facial expressions, namely, pleasant and unpleasant, and task relevance on P300 component of event-related brain potentials in the 3-stimulus version of the oddball task. Exp. 1 showed that, although the amplitudes of P300 were the largest in response to task-relevant target stimuli and moderate in response to task-irrelevant nontargets, the Pleasantness of stimuli did not affect the amplitudes of P300 when the stimuli were task-relevant or irrelevant. Data in Exp. 2 suggested that the emotional significance rather than physical characteristics of stimuli might be responsible for generation of P300 by task-irrelevant nontargets.     

Rapid acceleration of the lower arm correlates with agonist EMGs during the initial phase

Fifty-eight healthy subjects made rapid elbow extensions to a target over 54 degrees. Angular acceleration was measured and surface electromyograms (EMGs) were recorded from the antagonistic muscles using monopolar rather than bipolar electrode configurations. Marked individual differences were found in the peak value of the first derivative of acceleration (dAcc/dt_Pk). The dAcc/dt_Pk correlated with both quantitative and qualitative properties of the agonist EMGs, but not with those of the antagonist EMG. The agonist EMGs, integrated until the moment of dAcc/dt_Pk, were positively correlated with dAcc/dt_Pk. The interval between EMG onset and EMG peak decreased with increasing dAcc/dt_Pk. The duration of the initial negative phase in the EMGs, which was considered to index the time required to recruit high-threshold MUs, decreased with increasing dAcc/dt_Pk. The results indicate that the ability to rapidly accelerate the lower arm varies across subjects, probably due in part to individual differences in the neural capacity to drive the agonists.     

Effects of nonconscious perception on motor response

The present study reviews the literature on the empirical evidence for the dissociation between perception and action. We first review several key studies on brain-damaged patients, such as those suffering from blindsight and visual/tactile agnosia, and on experimental findings examining pointing movements in normal people in response to a nonconsciously perceived stimulus. We then describe three experiments we conducted using simple reaction time (RT) tasks with backward masking, in which the first (weak) and second (strong) electric stimuli were consecutively presented with a 40-ms interstimulus interval (ISI). First, we compared simple RTs for three stimulus conditions: weak alone, strong alone, and double, i.e., weak plus strong (Experiment 1); then, we manipulated the intensity of the first stimulus from the threshold (T) to 1.2T and 2T, with the second stimulus at 4T (Experiment 2); finally, we tested three different ISIs (20, 40, and 60 ms) with the stimulus intensities at 1.2T and 4T for the first and second stimuli (Experiment 3). These experiments showed that simple RTs were shorter for the double condition than for the strong-alone condition, indicating that motor processes under the double condition may be triggered by sensory inputs arising from the first stimulus. Our results also showed that the first stimulus was perceived without conscious awareness. These findings suggested that motor processes may be dissociated from conscious perceptual processes and that these two processes may not take place in a series but, rather, in parallel. We discussed the likely mechanisms underlying nonconscious perception and motor response to a nonconsciously perceived stimulus.