Note 527 — Chapter XV · [512]

Pflüger's Archiv, vii, 639. Tigerstedt (Bihang till Kongl. Svenska Vetenskaps Akad, Handl., Bd. 8, Häfte 2, Stockholm, 1884) revises Exner's figures, and shows that his conclusions are exaggerated. According to Tigerstedt, two observers almost always rightly appreciated 0.05 or 0.06'' of reaction-time difference. Half the time they did it rightly when the difference sank to 0.03'', though from 0.03'' and 0.06'' differences were often not noticed at all. Buccola found (La Legge del Tempo nei Fenomeni dei Pensiero, Milano, 1883, p. 371) that, after much practice in making rapid reactions upon a signal, he estimated directly, in figures, his own reaction-time, in 10 experiments, with an error of from 0.016'' to 0.018''; in 6, with one of 0.005'' to 0.069''; in one, with one of 0.002''; and in 3, with one of 0.003''.