Geometrical shape discrimination by “Saimiri sciureus”

Discussion The major finding of this study was that avoidance continued to improve as ITI was decreased to approximately 1 sec. and that the improvement persisted when ITI was then increased. The improvement may be related to the fact that perseveration of responding after shock is more likely to result in avoidance responses when the ITI is short than when it is long and that this pattern of responding, once established, may persist when ITI is then increased. Agreeing with the results of the present study are those of a previous study dealing with ITI interval and discriminated avoidance (Pearl, 1963) and those of a study without an exteroceptive warning stimulus (Leaf, 1965). Interestingly, the use of short ITIs may in part account for the better avoidance with discontinuous shock as opposed to continuous shock (D'Amato et aI, 1964; Hurwitz, 1964). The continuous shock group in these studies received training at long ITIs in a manner similar to the procedure of the present study. But the discontinuous shock groups were trained with brief periodic shocks given every few sec. and the CS acted till the rats responded. So during a given trial of training there was a brief interval between successive shocks and no interval between shocks and the continually acting CS. References Chapman, J. A., & Bolles, R. C. Effects of UCS duration on classical avoidance learning of the bar-press response. Psycho/' Rep .. 1964, 14, 559-563. 0' Amato, M. R., Keller, O. M., & OiCara, L. Facilitation of discriminated avoidance learning by discontinuous shock. J. compo physio/. Psycho/,. 1964, 58, 344-349. 0' Amato, M. R., & Schiff, O. Long-term discriminated avoidance performance in the rat. J. compo physio/. Psycho/" 1964, 57, 123-126. Hurwitz, H. M. B. Method for discriminative avoidance training. Science, 1964, 145, 1070-1071. Leaf, R. C. Acquisition of Sidman avoidance responding as a function of S-S interval. J. compo physio/. Psycho/" 1965, 59, 298300. Meyer, O. R., Cho, C., & Wesemann, Ann F. On problems of conditioning discriminated lever-press avoidance responses. Psycho/' Rev., 1960,67, 224-228. Pearl, J. Intertrial interval and acquisition of a lever press avoidance response. J. compo physio/. Psychol .. 1963, 56, 710-712. Pearl, J., & Edwards, R. E. Delayed avoidance conditioning: warning stimulus (CS) duration. Psychol. Rep., 1962, 11, 375-380. Erratum Woodburne, L. S. Visual acuity of' 'Saimiri sciureus." Psychon. ScL, 1965, 3, 307-308. Woodburne, L. S. Geometrical shape discrimination by "Saimiri sciureus." Psychon. Sci., 1965, 3, 309.Both articles should have contained an acknowledgement that the research was supported by National Institutes of Health Grant NB-04521-02. 42 Psychon. Sci., 1966, Vol. 4  (...truncated)