Effects of maze geometry and experience on exploratory behavior in the rat

Rats were exposed twice in a rotated sequence to a series of six mazes, consisting of hexagonal alleys, balanced for different alley length and structural complexity. Locomotor activity increased with alley length and decreased with structural complexity of the mazes. Locomotion became less stereotyped with increased experience, showing an increasing number of turns, less constant velocity, loss of the initial preference for outward leading alleys and weakening of the forward tendency at reentry from side alleys into hexagonal alleys. In contrast to these qualitative changes of locomotion, the amount of activity remained almost unchanged throughout the experiment. The results suggest that these increases in locomotion complexity depend upon complex interactions between experience and stimulus content of the mazes.     

“Project Screen” — A Follow‐up Study of a Pre‐school Screening Battery

This study examines a pre‐school screening survey battery with an aim to validate it in terms of predicting school performance. Subjects participating in the screening were tested at the end of their first year at school. Analysis of the data, using a canonical correlation procedure, suggested elimination of a number of test items ‐‐ age, sex, age of walking, socio‐economic rating, Draw‐a‐Man Test, balance and posture, body image, perceptual motor match, height and weight. Measures of general ability, visual discrimination, visual reception, general development, receptive language, language concepts and positional concepts were the best predictors of school performance.     

The rewarding effects of number and surface area of food in rats

Visual cues have an important role in food preference for both rats and humans. Here, we aim to isolate the effects of numerosity, density, and surface area on food preference and running speed in rats, by using a forced-choice maze paradigm. In Experiment 1, rats preferred and ran faster for a group of multiple smaller pellets rather than a single large pellet, corroborating previous research (Capaldi, Miller, & Alptekin Journal of Experimental Psychology: Animal Behavior Processes, 15(1), 75–80, 1989). Further experiments tested the prevailing hypothesis that multiple food pieces are more reinforcing because they occupy a larger surface area. Experiment 2 controlled for numerosity by utilizing a continuous food: mashed potatoes flattened to cover a larger surface area or rounded into a ball. The rats preferred and ran faster for the flattened potatoes, suggesting surface area plays a role in quantity estimations. Finally, in Experiment 3, rats displayed no preference or difference in running speed between a group of scattered and clustered pellets when number of pellets were kept constant. Taken together, these results suggest that density has an important role in food perception—that is, the rewarding effect of higher numerosity or larger surface area is removed when the food does not fill out the entire space. Alternative explanations and implications for human diet are discussed.     

Adolescents earlier diagnosed as dyslexic show major IQ declines on the WISC-III

Adolescents (n=43) previously diagnosed as dyslexic/reading disabled had markedly lower IQ scores on the newly standardized Wechsler Intelligence Scale for Children (WISC-III) than on the earlier administered WISC-R. The declines for Verbal, Performance, and Full Scale IQs were 10, 12, and 11 points, respectively, which were twice as great as in a subset of the standardization sample given both versions of the WISC. The adolescents did not show a significant decline in standard scores from the Wide Range Achievement Test (Level I to Level II). However, only two subjects had current reading and spelling standard scores above the 25th percentile. The impact of lower WISC-III IQs on guidelines for classification of students as learning disabled is discussed.