When a person synchronizes finger tapping with an isochronous stimulus like a metronome, taps often precede stimuli by 100 ms or less. This phenomenon is called negative mean asynchrony (NMA). Two experiments were conducted to examine whether NMA is generated by the underestimation of inter-onset intervals (IOIs), and to examine the relation between NMA and beat-based timing. In Experiment 1, estimations of empty intervals were compared with those of filled intervals in duration and tempo tasks. Durations of empty intervals were estimated to be shorter than those of filled intervals. On the other hand, estimated tempos were the same for both empty and filled intervals. In Experiment 2, the synchronized finger-taps were compared between empty and filled intervals. NMA was observed in all conditions, but the synchronized error was greater for empty intervals than for filled intervals. These results showed that perceiving IOIs as shorter advanced the timing of taps but was not an essential factor causing taps to precede stimuli. It is considered that beat-based timing is not the cause of NMA.

Despite numerous Vertical–Horizontal Illusion (VHI) studies conducted since that of Adolf Fick in 1851, VHI has yet to attain a uniformly accepted consensus due to conflicting conclusions. As a result, a re-examination of VHI was undertaken focusing on contact position of a vertical (mast) line on a horizontal (base) line, orientation of the VHI stimulus, and viewing conditions, i.e., monocular vs. binocular-vision. In pseudorandom fashion on a computer, 35 adults adjusted mast lines of varying length and contact position in reference to a 50-mm base line to the same perceived length as the base line. The Point of Subjective Equality (PSE) was measured over 168 trials (two trials of 7 contact positions×4 orientations×3 viewing conditions). Perceived lengths were significantly affected by contact position in an M-shaped manner (Marma et al., 2015) rather than V-shaped (Künnapas, 1955a), and PSE was shorter when the baseline was horizontal rather than vertical, confirming the anisotropy in vertical–horizontal axis (Künnapas, 1955a).

While simple reaction time (RT) is known to be substantially affected by diverse stimulus parameters, subjective temporal judgments about the onset timing of stimulus are relatively accurate. Here we tried to find the neural correlates of RT and subjective temporal judgment by comparing MEG signals evoked by random-dot coherent-motion onset with these behavioral measures. For the same motion stimuli, participants performed both a simple RT task, and a simultaneity judgment task with respect to a beep. The effect of motion coherence was much smaller for the point of subjective simultaneity (PSS) than RT. Changes in RT and PSS could both be predicted by the time when temporally-integrated motion responses crossed a threshold. The threshold was lower for PSS than for RT, suggesting that the brain assigns the time marker for timing perception prior to stimulus detection. Existence of temporally integrated neural signals in the brain will be discussed in light of recent literature.

Individual differences in reaction time are usually considered as noises in the study of cognitive psychology. In some situations, however, the individual differences provide useful insights for understanding the mechanism of human cognition. In this article, we focus on the experience of action video games and athletes as such examples and selectively review these studies. In addition, we briefly summarize web-based experiments that have been recently attracting psychologist. Web-based experiments have a benefit to easily increase a sample size and thereby a statistical power. However, one may wonder about the reliability of web-based studies. Therefore, we try to discuss the reliability especially in terms of the accuracy of stimulus presentation duration and reaction times recording.

Psychologists have analyzed response time data by their rules of thumb. Modern advances of statistical methods promote to create a new practice. Traditionally, outliers were discarded prior to statistical test and skewed data were converted by logarithms. Fitting approach reminds that analyzers intend to estimate parameters for RT distributions. In statistical tests, psychologists often conducted ANOVA by aggregating data across different trials in the same condition. This practice loss precision information of measurement. Linear mixed models is changing the situation. While practical issues are remain for several aspects of applying linear mixed model, consensus among psychologists would be increasingly required.

Recently Web-based/online psychological studies have been reported, in which web browsers familiarized by participants such as Microsoft Edge, Apple Safari, and Google Chrome are used for presenting stimuli and recording responses. The present article summarizes advantages and disadvantages of conducting Web-based experiments, and provide brief explanations of the knowledge required to create the programs. Technically speaking, it is better to know HTML, CSS, JavaScript (frameworks), and web servers. Web-based studies will be conducted more broadly in psychology because researchers can recruit more efficiently large and diverse samples from crowdsourcing marketplaces than from traditional participant pools.

We aimed to develop JIZAI (freedomization) body technology to enable us to act freely with sense of agency in corporation with robots and AI (artificial intelligence), and understand psychological and neurological mechanisms for the JIZAI body in JST-ERATO Inami JIZAI Body Project. Based on the scientific findings, we are trying to updating perspective of human body in the future society.