Habit reversal in the turtle

Two groups of mature “painted” turtles were trained in a T-maze. One group had five trials per day, with correct and incorrect turns reversed for each animal whenever it reached the criterion of five errorless trials on a given day. The second group had 10 trials per day, with correct and incorrect turns reversed daily, irrespective of the performance of the animals. Only in the data for the second group did there appear some indication of progressive improvement in habit reversal. The results are considered in relation to those obtained in analogous experiments with other species.     

Shock-induced threat and biting by the turtle

Shock-induced biting and threat by the male painted turtle (Chrysemys picta marginata) were studied in three experiments. When restrained facing each other, the turtles threatened and bit other turtles in response to electric shock. Shock alone caused turtles to threaten an unshocked turtle; the movements of a shocked turtle were sufficient to cause an unshocked but restrained turtle to threaten. When the turtles were free to move, they avoided an encounter when shocked, even reversing a strong position preference in order to do so.     

Orogastric, hydrational, and behavioral controls of drinking following water deprivation in rats.

Drinking and its associated behaviors were studied in rats deprived of fluid for 8,24, or 48 hr. The behavior of rats drinking water could be divided into three successive stages: (a) an initial intense burst of drinking that could not be easily disrupted; (b) intermittent drinking, often distinguished by the brief appearance of conflict behavior directed at the drinking spout; and (c) termination of drinking. Drinking stopped well before the fluid loss, reflected in a sizable extracellular deficit, was restored. Intake of water was terminated when serum hyponatremia and hypoosmolality (and presumably cellular overhydration) developed in temporal continguity with drinking. These and other considerations suggest that the cellular fluid phase exerts significant inhibitory as well as excitatory control over drinking.     

A further study of partial reinforcement in the turtle

Two matched groups of mature painted turtles, Chrysemys picta picta, were trained in a simple runway, one with partial and the other with consistent reinforcement, following which both groups were extinguished. The partially reinforced animals ran more slowly in acquisition, but showed somewhat greater resistance to extinction. The results are compared with those obtained in analogous experiments with other animals.     

Problem drinking in the family and youth suicide

Drawing from the work of Danigelis (1983), the present research put forth a theory of chronic stress to further our understanding of the processes related to suicide among 10- to 14-year-olds. Specifically, the relationship between problematic drinking in the home and youth suicide rates was examined. The hypothesis that chronic stress, as measured by problem drinking in the home, is related to youth suicide was supported.