Eyelid conditioning as a function of unconditioned stimulus intensity and intertrial interval.

Distribution of practice and the Müller-Lyer illusion1

“…According to HUll's theory (1943) distributed practice should produce better results than massed practice, since this allows for the reactive inhibition which has built up to dissipate between trials. Hull's prediction has been confirmed as it relates to eyeblink conditioning (Spence & Norris, 1950;Prokasy, Grant & Myers, 1958). It has also been supported by work on such motor skill tasks as upside down alphabet printing (Kientzle, 1946) and the pursuit rotor task (Ammons, 1950).…”

The Acquisition of Conditioned Emotional Response as a Function of Intertrial Interval

“…IT1 procedure over a number of sessions which made imposible any direct measure of a relationship between IT1 and conditioning efficiency. The studies by Spence and Norris (1950) and Prokasy et al (1958), using ITI's ranging from 9 to 135 s, demonstrated that acquisition of conditioning increased in efficiency in terms of yo CRs recorded as IT1 duration was extended, with asymptotic levels at the longest ITIs.…”

Sympathetic responding to unconditioned stimuli predicts subsequent threat expectancy, orienting, and visuocortical bias in human aversive Pavlovian conditioning

“…The physical intensity of the UCS has been shown to moderate the strength of acquisition, robustness of the conditioned response and heightened resistance of acquired defensive tendencies during extinction learning (Prokasy et al, 1958; Walker, 1960; Dragoin, 1971; Rescorla & Wagner, 1972). In addition to the physical intensity of the UCS, recent research has begun to investigate the other side of the equation: To what extent the organism’s reactivity to the UCS predicts conditioned responses.…”