Wobbling appearance of a face induced by doubled parts

An illusion produced by duplicating facial parts, which can cause an unstable feeling for many observers, was investigated. We examined factors that contribute to the unstable feeling. The results suggest that this illusion is specific to face perception, and the unstable feeling may be generated by difficulty in keeping attention directed to either of the duplicated facial parts.     

Reliability of familiarity rating of ordinary Japanese words for different years and places

Two-word familiarity sets were measured in different years (1995 and 2002) and places (Kanto and Kinki, in Japan) for a large number of Japanese words, to examine the reliability of familiarity ratings. The correlation between the word familiarities of the two sets was extremely high (r = .958, N = 10,515). It is suggested that familiarity rating, at least for ordinary words found in a dictionary, is very reliable and not greatly affected by differences in years and places.     

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.