RFT stability or failure to arouse?

Abstract

Oltman (1964) reported that loud white noise delivered through earphones facilitated Rod-and-frame Test (RFT; series 3 ) performance for male Ss. Later replication of the above finding with 1 6 female Ss showed that 100-db noise produced an average increase in RFT accuracy of 1.65 and I 5 of 1 6 Ss showed improvement (personal communication). H e concluded that individual differences in field dependence may be due in part to differences in level of arousal, which in turn, affects breadth of attention.'' Olunan's findings suggest that stimuli associated with other sense modalities might also affect RFT performance in similar ways. In order to test the generality of the above finding for other sense modes, two experiments were performed in which vibratory stimulation, provided by a 60-cycle massage vibrator, was randomly applied to the shoulder musculature of each S during RFT (series 3 ) responding. In both experiments, 2 0 female introductory psychology students were randomly assigned to an experimental group and 2 0 to a control group. In the first experiment, both groups received three blocks of 8 RFT trials followed by 5 min. rest between blocks; however, the experimental group received 30 sec. of vibratory stimulation preceding each of the 8 trials of the second block. The control group did not receive vibration and spent the equivalent amount of time talking with E. All treatments were administered by the second author. Resulting means and standard deviations for each of the three blocks of 8 trials were: Experimental Ss ( 1 ) 3.17 and 3.13, ( 2 ) Vibration 3.18 and 3.12, ( 3 ) 3.06 and 2.19; Control Ss, ( 1 ) 2.66 and 2.22, ( 2 ) 2.84 and 2.18, ( 3 ) 2.43 and 1.75. The means and standard deviations clearly show that vibration did not affect RFT responding. Since 8 30-sec. applications of vibratory stimulation did not improve RFT performance, it was decided to use 4 min. of sustained vibration with different Ss in a second experiment. The experimental group received 8 trials in the RFT followed by 5 min. rest, 4 min. of sustained vibration, and 8 more RFT trials. The control group talked with E during the 4-min. [vibration control] period. Means and standard deviations were: Experimental Ss, Pre 3.07 and 2.27, Post 2.20 and 1.16; Control, Pre 2.34 and 3.25, Post 2.49 and 3.51. Of 20 Ss 1 2 who received vibration showed some improvement in RFT responding as did nine of 20 Ss in the control group. An analysis of covariance showed that vibration did not affect RFT performance. Failure of the present experiments to obtain results similar to Oltman's suggests that either physiological arousal was not involved in his observarions or that 60-cycle vibratory stimulation was not sufficiently arousing for Ss in this study. If the latter is the case, it would stand in contradiction to Ss' verbal reports. A number of Ss reported the vibrator to be unpleasant and distracting while a few reported blurred vision but none thought that vibration had affected their performance. As it turned out, Ss were correct in assuming that their performance did not change beyond the normal range of variation found in RFT responding. The present results may simply reflect the relative stability of RFT performance in spite of numerous attempts to alter it experimentally.