Bert Forrin

Age, Speed of Information Processing, Recall, and Fluid Intelligence.

Abstract On three occasions, 63 adults, ranging in age from 26 to 80 years, all in good health, were tested with three speed of information-processing paradigms (the Sternberg, the Posner, and the Hick), two long-term free-recall tasks, and, as a measure of fluid intelligence, the Raven Advanced Progressive Matrices (RAPM) test. Whereas within-condition latencies for the three of the information-processing tasks and recall scores were found to be reliable and consistently correlated with age and RAPM, individual differences in within- condition accuracies and between-condition slopes produced by the three information- processing tasks were found to be unstable over time and unrelated to age and RAPM. As suggested by Salthouse (1985), a large portion of the age-related differences in fluid intelligence was found to be accounted for by age-related declines in a general latency factor (cognitive speed). Furthermore, in agreement with Salthouse, this general latency factor appeared to reflect more than what can be accounted for by the simplest of information-processing tasks (simple reaction time). Finally, given that free recall had a substantial independent effect on RAPM when age and latency were held constant, the results called into question the assumption that cognitive speed can account for all individual differences in IQ.

Inspection Time and Intelligence: Practice, Strategies, and Attention

Abstract Prior studies have shown that Inspection Time (IT) is moderately correlated with IQ. Typically, investigators have asserted that a shared mental speed factor is responsible for this correlation. Three experiments examined the effects of practice, response strategies, and attentiveness on inspection time and its relation to IQ. Results from Experiment 1 illustrated that IT improves over occasions and that, with improvement, the strength of the IT–IQ correlation is attenuated. Using accuracy rates from the longest stimulus durations in the IT task as an index of attentiveness, results from Experiment 2 suggested that attentiveness is at least in part responsible for the IT–IQ correlation. Although results from Experiment 3 further suggested that attentiveness contributes to individual differences in IT, the results also suggest that other processes, perhaps related to mental speed, contribute to the IT–IQ correlation.

THE EFFECTS OF POST-WEANING ENVIRONMENT, BIOLOGICAL DAM, AND NURSING DAM ON FEEDING NEOPHOBIA, OPEN FIELD ACTIVITY, AND LEARNING

Using rats in a cross-fostering design we examined the effects of pre- and post-weaning rearing environments on feeding neophobia, open field activity, runway training, and visual discrimination learning. Fostering had no effect on the offspring behaviors. The animals reared, post-weaning, in an enriched environment consumed more food in a novel situation, were less active in the open field, and learned the first of two discrimination tasks faster than did the animals reared in the standard condition. Inter-correlations among these measures were nonsignificant, suggesting that the effect of environment on learning cannot be reduced to temperamental factors. The deficit in learning resulting from rearing in standard environment does not, however, appear to be irreversible; animals reared in the standard condition reached performance levels on the second discrimination task characteristic of those reared in the enriched environment.

Secondary reinforcing properties of informative and non-informative stimuli

This study compared the secondary reinforcing properties of two cues distinguished on the basis of their prior significance in a brightness discrimination problem: a cue discriminative for reinforcement but not present in the goal region (a non-redundant predictor of reward) and a cue present in the goal region but irrelevant to the acquisition of the required discrimination (a redundant predictor or reward). The findings suggest that both cues were equally effective in reinforcing a simple position habit.

Affect conditioning associated with the onset and termination of electric shock

The results of this study are consistent with the position that fear is more readily conditioned to a cue paired with the onset rather than the offset of a painful event. No evidence was found for the presumed secondary reinforcing properties of a cue associated with shock termination.

Keeping track of several variables: Number of variables and stimulus recurrence distributions

It can be easier to keep track of the states of many variables than to keep track of the states of few. This finding is attributed to changes in stimulus recurrence distributions (and required recency discriminations) which accompany changes in the number of variables to be monitored.