Learned taste aversions in rats as a function of delay,speed, and duration of rotation

Rats fed a saccharin solution and then rotated on a turntable showed an aversion to the saccharin solution on later testing. In the first experiment, the rats learned to avoid saccharin with delays of as much as 9 hr between drinking the saccharin and the start of rotation. The second experiment showed that the critical determinant of aversiveness of rotation was number of rotations. The rats avoided saccharin as much after rotation at high speeds for short durations as after rotation at low speeds for long durations.     

Developmental steps in the comparison and integration of information by grade-school children

The developmental sequence in 5- to 11-year-old children's attempts to combine two discrete stimuli was investigated by microanalysis of answers in an equivalence task. Eleven response types were identified and shown to form both a developmental and a hierarchical sequence of comparison and integration operations. An age-related progression in response abstractness was also found and a significant interrelation with response type was demonstrated. The evidence supported a construct of verbally mediated executive control over the interactions of short- and long-term memory.     

The development of cognitive mapping of the large-scale environment

Two experiments were conducted to investigate the development of children's cognitive maps of large-scale environments. Kindergarten (Mean Age = 5?7), second (Mean Age = 7?7), and fifth (Mean Age = 10?7) graders walked through a large model town and were then required to construct the layout of building in that model from memory. Accuracy of construction increased as a function both of developmental level and repeated encounters with the layout. In Experiment 1, the separate effects of repeatedly walking through the town and repeatedly constructing it both increased the accuracy of the children's reconstructions. In Experiment 2, walking through the environment was no more effective than merely viewing it repeatedly. Young children's accuracy in bounded space (Experiment 1) was far more accurate than their performance in unbounded space (Experiment 2), while older children's accuracy was relatively unaffected by this variable.     

Children and adults' distance estimations in a large-scale environment: effects of time and clutter

In two experiments adults (mean age = 19-5), sixth graders (mean age = 11-8), fourth graders (mean age = 9-8), and second graders (mean age = 7-8) walked a straight line distance through a large-scale environment. Subjects were then asked to estimate the time taken to traverse each half of the walk and to estimate the distance between objects seen along the walk. In Experiment 1 each half of the walk was traversed in the same amount of time but contained a different number of objects (clutter). Time and distance estimates were related, but were not affected by the number of intervening objects encountered between locations. In Experiment 2 subjects again encountered a different number of objects along each half of the walk but each half was traversed in varying amounts of time. Again, time and distance estimates were related, and there was no clutter effect. There were no consistent developmental differences across the two experiments. It was concluded that (1) Thorndyke's clutter effect does not occur across all types of spatial cognition tasks, and (2) children and adults tend to relate time and distance across a variety of distance estimation tasks.     

Preference as a function of the correlation between stimuli and reinforcement outcomes

Pigeons' preferences for stimuli that were to varying degrees correlated with outcomes were studied in two experiments using a concurrent-chain procedure. The pigeons chose between two terminal links, each ending with food reinforcement and with blackout on half of the trials. In the first experiment, one terminal link (nonpredictive or unreliable link) provided stimuli completely uncorrelated with the outcomes while the other terminal link (predictive or reliable link) provided stimuli that were, to varying degrees, correlated with these outcomes. All pigeons showed increasing preferences for the predictive link as the reliability of the stimuli in that link increased. In the second experiment, stimuli in both terminal links were differentially correlated with the outcomes. The pigeons again preferred the more reliably correlated terminal link. The relation between these results and the delay-reduction hypothesis and conditioned reinforcement account is noted. The behavioral value of predictive stimuli may lie in their permitting the organism to more effectively apportion its time between interim activities and terminal responses.