Horizontal Task Research Articles

Effects of lesions of the optic tectum on the ability of turtles to locate food stimuli.

In a previous experiment, it was demonstrated that the removal of portions of the optic tectum in a turtle, Podocnemis unifilis, impaired its ability to perform a horizontal vs. vertical line discrimination task. To further elucidate the nature of this deficit, turtles (P. unifilis) were operantly conditioned to locate a food object at varying positions in an aquarium. Preoperatively, all of the animals approach a food object in a direct manner. Animals with a bilateral lesion of the optic tectum approach the food object in an indirect manner. One animal, with a unilateral lesion approached the food object in both an indirect and a direct manner depending on the position of the object in the visual field.

Sex differences in the comprehension of spatial orientation.

This research examined effects of instruction upon acquisition of Piaget's concept of horizontality and determined sex differences related to this acquisition. Hypotheses tested were that there are no significant differences (a) in performance on perception and prediction tasks, (b) by sex in the ability to comprehend horizontality, (c) by sex in the stage of development after instruction, and (d) by sex after instruction on the number of correct responses on horizontal tasks. Subjects were 18 male and 17 female rural, public school pupils ranging in age from 8 years, 0 months to 9 years, 11 months. Test instruments were a cylindrical bottle half-filled with colored water and eight pictures of bottles positioned at angles from 0 to 315 degrees at increments of 45 degrees. Chi square tests indicated that males performed significantly better than females on perception and prediction, and that instruction significantly improved male performance on prediction and female performance on prediction and perception. It was concluded that females, if given instruction, could more closely approximate the performance of males on the horizontal water level task.