Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

On mediation

The mediation-nonmediation dichotomy proposed by the Kendlers (Psychological Review, 1962, 69, 1–16) and subscribed to by Cole and Medin (Journal of Experimental Child Psychology, 1973, 15, 352–355) is reviewed and critiqued. It is proposed that the appropriate question for research is how children mediate, not when they mediate.     

Comparison of reinforcement and punishment functions produced by the same contingent event in the same subjects

The same event, forced running, was used to reinforce the lever-pressing of six rats in one component of a multiple schedule and to punish their drinking in another component. When the durations of running were converted to probabilities that Ss would not be running at t + n sec, given that the run gegan at t = 0 sec, both reinforcement and punishment were found to be linear (inverse) functions of the probability of not-running. A high concordance (0.90) between slopes of the reinforcement and punishment functions indicated that individual Ss were either sensitive to both reinforcement and punishment or sensitive to neither.     

Different memory functions for consonants and vowels

Different memory functions were obtained for consonants (C) and vowels (V) in a serial recall task. In general, the most recently heard vowels in a sequence were easier to recall than the most recently heard consonants. This effect was observed for auditorily presented sequences of CV or VC syllables, but was not observed for visually presented stimuli. The results were explained in terms of a limited capacity acoustic storage in which vowels are preserved longer than consonants. Retrieval of the last vowels from this storage was presumed to cause the vowel recency effect.     

Asymmetries in the acquisition of polar adjectives: Linguistic or conceptual?

This study was designed to determine whether the asymmetry in children's acquisition of polar adjective pairs is based on linguistic factors related to differences in adult usage and frequency or on an underlying conceptual difference. 24 children, aged 3;7–4;11, took part in a concept-learning task in which nonsense syllables replaced English words for the positive and negative ends of four dimensions: size, height, length, and thickness. The data indicate that the syllables for the negative end of each dimension have a longer learning period and a greater prelearning error rate. These results support the hypothesis that the asymmetry observed in the acquisition of polar adjectives is based on an underlying conceptual asymmetry.