Isolation has permanent effects upon the behavior of the rat, but not the mouse, gerbil, or guinea pig.

In the rat isolation has both short- and long-term influences upon behavior. Rats isolated at any age will show increases in timidity and aggression, but both effects can be reversed by periods of social housing. However, isolation before 50 days of age has permanent effects upon behavior. We have previously found that rats between 25 and 45 days of age may be protected from the deleterious effects of isolation by short daily periods of social contact if, during these daily contact periods, the rats engage in intense bouts of rough-and-tumble play. In this study we examined the permanence of the effects of isolation on the rat, mouse, guinea pig and gerbil. As predicted by the play hypothesis, species which do not engage in extensive social play do not show permanent deficits if isolated prior to 50 days. Only rats which engage in long bouts of rough-and-tumble play between 20 and 50 days show any permanent behavioral effects of isolation during this period.

Effects of personality, perceptual difficulty and pacing of a task on productivity, job satisfaction, and physiological stress.

The relative psychological, physiological, and performance advantages and disadvantages of utilizing machine-paced and self-paced work were examined by having 12 subjects perform a marking-stapling task at 2 levels of perceptual difficulty and under 2 pacing conditions for 30 min. each. (a) 3 subjects who on the personality tests were identified as introverted, reserved, and trusting preferred to work in the machine-paced condition, while 9 subjects who were identified as extroverted, outgoing and suspicious preferred the self-paced condition, (b) the performance errors in machine-paced operation were 372% higher than for self-paced work, and (c) there were no differences between machine-paced and self-paced work on physiological variables, except for sinus arrhythmia for the task with high perceptual load, and quantity of production.