Differential rates of exhaustion and recovery of several parameters of male rat sexual behavior.

Sexual exhaustion of the male rat was studied with respect to several copulatory measures. The ejaculatory latency, intercopulatory interval, and intromission frequency demonstrate a U-shaped curve, exhibiting high values for the initial ejaculatory series, falling to a minimum at an intermediate ejaculatory series, and again increasing at exhaustion. The absolute refractory period of the postejaculatory interval (measured at vocalization termination) increases linerly, whereas the relative refractory period (the remaining portion of the postejaculatory interval) is a postively accelerating function. Partial recovery tests demonstrated that the preejaculatory measures and absolute refractory period have substantially returned to baseline values by Day 6, while the relative refractory period is still extended. The significance of these data to the theoretical modeling of sexual behavior is discussed.     

Relation between 22-kHz ultrasonic signals and sociosexual behavior in rats

The copulatory performance of male rats, tested in a large seminaturalistic environment, was assessed to determine the relation between 22-kHz ultrasonic vocalizations and a range of sociosexual behaviors. The male rats were tested until sexual exhaustion. Such ultrasonic signals were shown to occur in a wider range of sociosexual circumstances than previously reported; for example, the calls occcurred in particular social circumstances during the preejaculatory period as well as during the postejaculatory interval. There was no consistent evidence that the emission of this call during the postejaculatory period consistently functions to keep the female away from the male. The nature and occurrence of postejaculatory ultrasonic signals showed increasing variability in successive ejaculatory series. The results of this and previous studies are interpreted within a semiotic theory of communication. The 22-kHz call is described as a message that makes available the information that the sender is in a socially depressed and withdrawn state.     

Studies of instrumental behavior with sexual reinforcement in male rats (Rattus norvegicus): I. Control by brief visual stimuli paired with a receptive female

We describe a novel procedure for measuring instrumental sexual behavior in the male rat by using a second-order schedule of presentation of sexual reinforcement, an estrous female. Experimental assessment and validation of the paradigm have been achieved by examining (a) the importance of the conditioned stimulus in maintaining instrumental responding by measuring the effects of its omission during a test session, (b) the effects and motivational specificity on instrumental behavior of the postejaculatory refractory period (a period of sexual unarousability) and of satiety for food by measuring the impact of each manipulation on animals working for food and for a female, (c) the effects of replacing an estrous female with an anestrous one as the earned reward, and (d) the correlations between conditioned and unconditioned measures of sexual behavior. We conclude that the second-order paradigm provides a means of distinguishing between the effects of neuroendocrine manipulations on incentive motivational and performance variables underlying the expression of sexual behavior.     

Ejaculate disruption in two species of voles (Microtus): on the PEI matching law.

We permitted male prairie and montane voles (Microtus ochrogaster and M. montanus) five thrusts, without ejaculation, with a female at variable times after a 1st male ejaculated. In both prairie and montane voles, there were fewer sperm, in relation to control conditions, in the female's tract 1 hr after ejaculation if the female received thrusts immediately or 15 min after the ejaculate. There was no such effect after a 50-min delay. There was no significant decrease in litter production in prairie voles caused by thrusts delivered either immediately or after a 15-min delay. Sperm transport in these species is susceptible to disruption for a longer period than in deer mice or rats. The proposal that the postejaculatory interval protects a male from disrupting its own sperm transport (the PEI matching law) appears not to hold for these species.     

Facilitation of the effect testosterone on male sexual behavior in rats deprived of REM sleep

The possibility of rapid eye movement sleep deprivation (REMd) altering the effect of testosterone on masculine sexual behavior was investigated. Adult castrated male Wistar rats with no sexual experience were randomly assigned to the following three groups: REMd (using the water tank technique) for 7 days, large platform control for 7 days, and undisturbed sleep control. All subjects were treated with 1 mg testosterone propionate daily for 14 days. Masculine sexual behavior was assessed 3 consecutive days prior to steroid administration and was evaluated daily during the treatment. Frequencies and latencies of mounts, intromissions, and ejaculations, as well as the postejaculatory refractory period were recorded. One hundred percent of the REMd subjects presented mounts, intromissions, and ejaculations sooner than the control group. In almost all parameters, a clear facilitation of sexual activity was observed in the REMd group.     

From mouth to hand: gesture, speech, and the evolution of right-handedness

The strong predominance of right-handedness appears to be a uniquely human characteristic, whereas the left-cerebral dominance for vocalization occurs in many species, including frogs, birds, and mammals. Right-handedness may have arisen because of an association between manual gestures and vocalization in the evolution of language. I argue that language evolved from manual gestures, gradually incorporating vocal elements. The transition may be traced through changes in the function of Broca's area. Its homologue in monkeys has nothing to do with vocal control, but contains the so-called "mirror neurons," the code for both the production of manual reaching movements and the perception of the same movements performed by others. This system is bilateral in monkeys, but predominantly left-hemispheric in humans, and in humans is involved with vocalization as well as manual actions. There is evidence that Broca's area is enlarged on the left side in Homo habilis, suggesting that a link between gesture and vocalization may go back at least two million years, although other evidence suggests that speech may not have become fully autonomous until Homo sapiens appeared some 170,000 years ago, or perhaps even later. The removal of manual gesture as a necessary component of language may explain the rapid advance of technology, allowing late migrations of Homo sapiens from Africa to replace all other hominids in other parts of the world, including the Neanderthals in Europe and Homo erectus in Asia. Nevertheless, the long association of vocalization with manual gesture left us a legacy of right-handedness.     

Receptivity of the female rat (Rattus norvegicus) after male devocalization: a ventral perspective

Male rats (Rattus norvegicus) emit at least two patterns of vocalization during copulation, the mating call and the pre-ejaculatory call. Both calls promote immobility of the female during lordosis, but the pre-ejaculatory calls are more effective. We undertook, through ventral observations of the mating pair, to determine if the female failed to assume or maintain the lordosis posture when mounted by a devocalized male and also to determine if the devocalized male was providing adequate stimulation to induce receptive behavior. Females were more likely to move away from the devocalized males before assuming the full lordosis posture. Furthermore, they were more likely to move away before the males had a chance to engage in intromissive behavior. However, when the females remained immobile long enough for the males to achieve a mount or intromission, there was little difference in the behavior of either animal that resulted from the devocalization of the male.     

Parallel processing and the psychological refractory period

The serial processor theory proposed by Welford is the traditional explanation of the delay in responding to the second stimulus presented in psychological refractory period paradigm experiments. This paper reviews results which do not accord either with that theory or with later modifications of it by Smith and Tolkmitt. To explain these results a model is proposed which contains three propositions: (a) parallel processing of concurrent stimuli, (b) fixed total processing capacity, (c) capacity allocation either dependent on the relative difficulty of the stimuli or set by the subject according to experimental instructions. The predictions of this model for the effects of stimulus difficulty and interstimulus interval on reaction time and interresponse interval are computed. These predictions are compared with those of other parallel processing models of the psychological refractory period which have been proposed by Herman and Kantowitz, by Kahneman and by Keele.     

Copulation and intermale aggression in rats

Attack behavior of reliably aggressive male Long-Evans rats against unfamiliar male intruders was observed immediately following copulation to one or more ejaculations. Compulatory series to five ejaculations did not differ from copulation to a single ejaculation or from a noncopulatory control in affecting aggressive behavior. Repetitive biting attacks occurred in all conditions, with comparable wounding. Evidently, the male postejaculatory state of insensitivity to sexual stimuli does not extend to stimuli eliciting intermale aggression. A second experiment determined the attack-eliciting capacity of foreign males placed in the home cage of an actively copulating male. As intromissions increased and the interval to ejaculation decreased, the probability of intermale aggression and interruption of copulation diminished. The results are discussed in reference to sexual and aggressive strategies of the copulating male.     

Social conditioning and its proper control procedures.

In Expt I, eight infants received response-contingent social stimulation, while another eight infants received response-independent social stimulation. Both groups' vocalization rates similarly increased from baseline to stimulation periods and decreased from stimulation to extinction periods. In Expt II, 12 infants were given continuous social stimulation (elicitation treatment) for one period, and, in a second period, stimulation was withheld for 5 sec contingent upon each vocalization (omission treatment). Response rates were similar for both periods, and rates decreased when social stimulation was removed (mobile treatment). In both studies social stimulation increased vocalization rates and rate of responding was insensitive to the programmed contingency. There were, however, fewer “bursts” of responses with the negative and positive contingencies as compared with response-independent stimulation.     

The limits of the “psychological refractory period”

Previous evidence on the psychological refractory period is shown to be inadequate on the crucial issue of whether delays, which cannot be overcome by practice, occur in responding to the second of two signals, when the interval between them is less than 0·5 seconds. For simple key pressing responses it is shown that when the interval between signals is less than the reaction time to the first signal, delays in the reaction time to the second signal occur in a predictable manner. When the interval is greater than the first reaction time, however, no such delays are found. Possible reasons for the discrepancy between these and earlier findings are suggested.     

Vocalization and looking behaviour of Down's syndrome infants.

The effect of contingent and non-contingent vocal stimulation on vocalization and looking behaviour was investigated for 10 Down's syndrome infants. There were two experimental sessions consisting of four stages, namely 1 min base-line, 1 min experimental condition, a further 1 min base-line and a final 2 min experimental condition. Maternal vocal stimulation was contingent upon infant vocalization for the experimental conditions of one session and was presented every 10 s independent of infant vocalization for the experimental conditions of the other session. Neither condition increased infant vocalization but there was a significant decrease in looking at mother during the base-line stages which followed maternal vocalization (F = 5.07, d.f. = 4, 28, P less than 0.01). It is suggested that looking behaviour may be an important indication of competence in pre-linguistic social communication for developmentally delayed infants.     

Some temporal factors in the successive comparison of auditory amplitudes.

Under certain conditions the discrimination of successively presented auditory amplitudes appears to be primarily a function of the time intervals between stimulus onsets rather than of either the duration of the stimulus or the silent interval between the tones (interstimulus interval). The results of this study are interpreted in terms of a model containing an acquisition process which continues for a set interval (about 600 msec) subsequent to the onset of the stimulus, even if stimulus offset occurs prior to this time. The onset of another stimulus during this period terminates acquisition. The model also includes a memory process which does not start until acquisition is complete.     

Motivational control of sexual behavior in Aplysia fasciata: sequencing and modulation by sexual deprivation and by addition of partners

Variables similar to those affecting feeding behavior also modulate sexual behavior in Aplysia fasciata, indicating that mating is under motivational control. Motivated behaviors are often patterned into appetitive and consummatory components. Courtship, the appetitive phase of male sexual behavior, was temporally related to subsequent mating. Although many bouts of courtship failed to lead to mating, most incidents of mating were preceded by courtship. Motivation is also characterized by satiation after the goal of the behavior is achieved. We found an increase in likelihood to mate following a period of sexual isolation. Motivated behaviors are also modulated by environmental stimuli that induce arousal. Time spent mating was found to be a function of the number of potential mates accessible for mating. Number of A. fascinata participating in a mating group was also found to be a function of number of potential mates available.     

Age of acquisition and word frequency effects in picture naming: a dual-task investigation

In 2 experiments, the authors explored age of acquisition (AoA) and word frequency (WF) effects in picture naming using the psychological refractory period paradigm. In Experiment 1, participants named a picture and then, a short time later, categorized 1 of 3 possible auditory tones as high, medium, or low. Both AoA (Experiment 1A) and WF (Experiment 1B) effects propagated onto tone discrimination reaction times (RTs), with the effects of AoA being stronger. In Experiment 2, the to-be-named picture followed the auditory tone by a varying interval. As the interval decreased, picture naming RTs increased. The relationship between the interval and AoA (Experiment 2A) was reliably underadditive; AoA effects were eliminated at the shortest interval. In contrast, WF (Experiment 2B) was additive with the effects of the interval. These results demonstrate an empirical dissociation between AoA and WF effects. AoA affects processing stages that precede those that are sensitive to WF. The implications for theories of picture naming are discussed.     

Uses of double-pulse stimulation behaviorally to infer refractoriness, summation, convergence, and transmitter characteristics of hypothalamic reward systems.

To self-administer trains of pulse pairs, rats with electrodes in the hypothalamic reward system would press a lever at lower current thresholds or faster latencies, the shorter the intrapair interval--unless the interval was so short that each second pulse fell within the refractory period following the first. By delivering all second pulses to the contralateral reward system not only was this refractory period limitation on temporal summation circumvented but spatial summation of the two reward systems was demonstrated. Evidently, they converge somewhere upon common neurons. Nearby nonreward structures did not share in this convergence. Assuming that the temporal-summation decline at longer intrapair intervals reflected the course of transmitter disposal at the synapse, imipramine and diisopropylfluorophosphate were peripherally administered. These drugs, which retard disposal, respectively, in adrenergic and cholinergic synapses, indeed prolonged temporal summation, thus, supporting the assumption and implying that adrenergic and cholinergic mechanisms both mediate self-stimulation.     

The dual-task SRT procedure: fine-tuning the timing

In the standard sequential reaction time study, subjects are presented with a repeating sequence of targets to which they must respond as rapidly as possible. With practice reaction times decrease, suggesting a learned ability to exploit the repeating patterns in the display. In a common variation, a second task is interposed, typically a tone-counting task in which subjects must keep track of the frequency with which particular tones occur. In the canonical experiment, these tones appear at varying times in the interval between the subjects’ response to a target and the next target. Data are presented that show that this latter variable (the RSOA, response-secondary stimulus onset asynchrony) actually plays an important but previously hidden role in these experiments. A model based on an extension of the notion of the psychological refractory period is introduced to explain these findings.     

THE IMPORTANCE OF TIME FOR THE INTROMISSION FREQUENCY IN THE MALE RAT MATING BEHAVIOUR

L arsson , K. The importance of time for the intromission frequency in the male rat mating behaviour. Scand. J. Psychol . 1961, 2 , 149–152.—A prolongation of the intervals separating the intromissions in the male rat mating pattern produces a decrease in the number of intromissions to ejaculate. By comparing the length of the interval effective in inducing a reduction of the response frequency in two groups of subjects, one composed of extremely 'slow' animals and another of extremely 'fast' ones, it was found that the appearance of the reduction effect was dependent on the length of the interco-pulatory interval characteristic of the individual. A reduction appeared in all animals when the interval of enforced rest was longer than the normal inter-copulatory interval.     

How to Bootstrap a Human Communication System

How might a human communication system be bootstrapped in the absence of conventional language? We argue that motivated signs play an important role (i.e., signs that are linked to meaning by structural resemblance or by natural association). An experimental study is then reported in which participants try to communicate a range of pre‐specified items to a partner using repeated non‐linguistic vocalization, repeated gesture, or repeated non‐linguistic vocalization plus gesture (but without using their existing language system). Gesture proved more effective (measured by communication success) and more efficient (measured by the time taken to communicate) than non‐linguistic vocalization across a range of item categories (emotion, object, and action). Combining gesture and vocalization did not improve performance beyond gesture alone. We experimentally demonstrate that gesture is a more effective means of bootstrapping a human communication system. We argue that gesture outperforms non‐linguistic vocalization because it lends itself more naturally to the production of motivated signs.     

The speech and vocalization patterns of boys with ADHD compared with boys with dyslexia and boys without learning disabilities

This research study dealt with an inquiry into the speech and vocalization patterns of boys with Attention Deficit Hyperactivity Disorder (ADHD) who were not under the influence of stimulating medication, compared with the speech and vocalization patterns of boys with reading disabilities and a control group of learners without learning disabilities. The voices of 105 participants were recorded during interviews and analyzed in the laboratory using equipment that examined the temporal speech patterns and physical features of vocalization. The speech patterns were examined with a frequency examination, speech unit length duration, and correlation between the vocalization and pauses in the speech unit. The physical features of vocalization were examined with volume and frequency scales. The research results indicated that the speech and vocalization patterns of boys with ADHD were significantly different from those of boys with reading disabilities and from the boys in the control group. The results support the assumption that speech and vocalization indicators can be used as objective indicators for the diagnosis of hyperactivity syndrome with attention and concentration difficulties.