Journal of comparative and physiological psychology最新文献

Male, spayed female, and pseudohermaphroditic female dogs were tested in pairs for competition over a large bone. Pseudohermaphroditic females had been exposed to testosterone proprionate before and immediately after birth. Two types of tests were used. In equal opportunity tests (EO tests), both members of a pair had equal chance to seize the bone when it was tossed into the arena. Each EO test was followed by an established possession test (EP test). During an EP test, the loser of the preceding EO test was given possession of the bone before the former winner was returned to the test arena. Every dog was tested against all other members of its own and both of the other groups. Males won 78 of 100 EO tests against normal females but only 61 of 100 against pseudohermaphroditic females. Pseudohermaphroditic females won 70 of 100 EO tests against normal females. When either normal or pseudohermaphroditic females were given possession of the bone in EP tests they were equally ineffective in defense against male challengers, losing 75% and 71% of their tests, respectively. Both types of females were much more successful in defending possession during EP tests against each other than they had been against males. When normal and pseudohermaphroditic females were treated with testosterone propionate, their performance in competition tests was not altered. Androgenic stimulation before and immediately after birth permanently modified the social behavior of pseudohermaphroditic females as well as the behavior of males and normal females toward the experimental dogs. However, the changes could not appropriately be described as "masculinization." Developmentally androgenized females differed from members of their own sex, but they differed just as greatly from normal males.

Inescapably shocked rats perform poorly on a two-way shuttle box escape task 24 hr after the shock. Because inescapably shocked rats become analgesic upon reexposure to a small amount of shock 24 hr after inescapable shock, they are likely to be analgesic during the shuttle box escape task. Subjects receiving an equivalent amount of escapable shock display neither the escape dificit nor the analgesia. Both the analgesia and the escape deficit respond in a similar fashion to the manipulation of a variety of other variables. These findings have led to the suggestion that the analgesia ("long-term analgesia") may cause the inescapable-shock-produced escape deficit. However, the present experiments demonstrated that two pituitary manipulations that completely eliminate the analgesia have no effect on the escape deficit. Both hypophysectomy and dexamethasone administration blocked the analgesic consequences of inescapable shock but did not reduce the magnitude of the escape deficit. Therefore, the long-term analgesia produced by inescapable shock does not cause the deficit in shuttle box escape performance displayed by inescapably shocked rats. Furthermore, these results indicate that the pituitary is not essential in the production of this escape deficit.

The acoustic startle reflex in the rat is inhibited if a relatively weak stimulus precedes the startle-eliciting tone burst. This research explored the effect of brief silent periods (gaps) in white noise on the startle reflex, in order to describe the limits of temporal resolution in the auditory system of the rat. Brief silent periods did depress reflex behavior, and two responsible processes were identified. One was most evident at a 190-msec lead time between gap and startle tone. It yielded a linear decrement in reflex expression over a dynamic range of 0-7 msec, and an estimate for the threshold of temporal acuity of 3.5 msec. The second was evident primarily at a 40-msec interstimulus interval and had a linear effect over a dynamic range of at least 40 msec. Very brief gaps had a greater inhibitory effect at the 190-msec interval between gap and startle stimulus; prolonged gaps had their greater effect at the 40-msec interval. The first process was identified as reflex inhibition, which is sensitive to the sensory properties of the lead stimulus. The second process was identified as sensory adaptation, produced by noise exposure but unmasked by silence.

The salt appetite of the rat is useful for studying certain behavioral and neurological functions. A refined method for inducing and measuring salt appetite for these purposes is described, and the efficiency and reliability of the procedures are demonstrated by parametric studies comparing the appetite behaviors of male and female rats. The method for inducing salt appetite couples 2 days of dietary sodium deprivation with a brief diuretic treatment. The measurement procedure involves a 2-hr period of access to one of several sodium chloride solutions differing in palatability or concentration. The induction procedure allowed precise control of drive levels, and the measurement procedure yielded highly reliable results as a function of the properties of the incentives. Female rats consistently ingested about twice as much sodium chloride solution as did male rats regardless of the palatability of the solution or of body sodium levels. At the same time, female rats lost less sodium in urine following diuretic treatment.

A young Indian elephant was tested to determine its absolute sensitivity, frequency-discrimination thresholds, and sound-localization thresholds. The elephant was found to have an audibility curve similar to that of other mammals but one that is more sensitive to low frequencies and less sensitive to high frequencies than any other mammalian audiogram including human's. The elephant's sensitivity to frequency differences at low frequencies was found to equal that of humans. Finally, the elephant was found to be very accurate at localizing sounds in the azimuthal plane, with thresholds around 1 degree for broad-band noise. The elephant's ability to localize pure tones suggested that it could use both binaural time- and intensity-difference cues to localize sound.

The current study was designed to examine the possibility that odor from substances rubbed on the back of young stimulus animals will influence the social behavior of male Mongolian gerbils. Thirty adult subjects were tested for four 5-min sessions with young conspecifics that had water, perfume, urine, or ventral gland sebum rubbed on their back. The subjects showed significantly longer investigation duration and higher approach frequencies toward the subjects treated with urine or sebum. The results demonstrate that gerbils are attracted to relevant odors in a social situation.

Daily subcutaneous injections of estradiol, progesterone, and testosterone were given to ovariectomized rhesus monkeys in amounts that imitated accurately the changing plasma levels of hormones in intact females with natural menstrual cycles. Because these cycles in ovariectomized, treated females were terminated by normal vaginal bleeding every 28 days and showed a mid-cycle gonadotropin surge, we termed them "artificial menstrual cycles." In dyadic mating tests, changes in the females' access times (lever pressing) for males, and in the males' ejaculatory performance, were closely similar during natural and artificial cycles, and there were well-marked behavioral rhythms. These rhythms were lost during 28-day control periods when ovariectomized females received injections of vehicle alone. Differences in ejaculatory performance during natural and artificial cycles could be accounted for by an order effect. It is concluded that the artificial cycle provides a valid and useful paradigm for a more detailed study of the neuroendocrine regulation of primate reproductive behavior.

The effects of winning or losing on subsequent aggressive behavior in male and female rats were studied. By using three strains of rats with different levels of aggression, a procedure was developed to create winners and losers. Subsequently, winners were tested against losers. Behavioral analysis of all tests enabled a thorough study of these processes and of their consequences. The results indicate that significant and relatively permanent behavioral changes are induced in intact and castrated, testosterone-treated males but not in females. The results suggest that behavioral inhibition is a specific characteristic of the male's agonistic behavioral repertoire.