Relations among heart rate, immediate memory, and time estimation under two different instructions

The present study was done to elucidate the relations among heart rate, digit memory, and time estimation under two different instructions, standard and evaluative. 60 women heard and recalled 8 digits. Subjects reproduced 4-, 8-, and 16-sec. durations of a buzzer and also estimated the durations. Data were discussed in terms of the hypothesis of an inverted U-shaped relationship between arousal and performance. These data suggest relations among the three variables which were influenced by two different instructions.