The operant control of vocalization in the dog

Neural processes of vocal social perception: Dog-human comparative fMRI studies

In this review we focus on the exciting new opportunities in comparative neuroscience to study neural processes of vocal social perception by comparing dog and human neural activity using fMRI methods. The dog is a relatively new addition to this research area; however, it has a large potential to become a standard species in such investigations. Although there has been great interest in the emergence of human language abilities, in case of fMRI methods, most research to date focused on homologue comparisons within Primates. By belonging to a very different clade of mammalian evolution, dogs could give such research agendas a more general mammalian foundation. In addition, broadening the scope of investigations into vocal communication in general can also deepen our understanding of human vocal skills. Being selected for and living in an anthropogenic environment, research with dogs may also be informative about the way in which human non-linguistic and linguistic signals are represented in a mammalian brain without skills for language production.

Rhythmic entrainment: Why humans want to, fireflies can't help it, pet birds try, and sea lions have to be bribed

Until recently, the literature on rhythmic ability took for granted that only humans are able to synchronize body movements to an external beat-to entrain. This assumption has been undercut by findings of beat-matching in various species of parrots and, more recently, in a sea lion, several species of primates, and possibly horses. This throws open the question of how widespread beat-matching ability is in the animal kingdom. Here we reassess the arguments and evidence for an absence of beat-matching in animals, and conclude that in fact no convincing case against beat-matching in animals has been made. Instead, such evidence as there is suggests that this capacity could be quite widespread. Furthermore, mutual entrainment of oscillations is a general principle of physical systems, both biological and nonbiological, suggesting that entrainment of motor systems by sensory systems may be a default rather than an oddity. The question then becomes, not why a few privileged species are able to beat-match, but why species do not always do so-why they vary in both spontaneous and learned beat-matching. We propose that when entrainment is not driven by fixed, mandatory connections between input and output (as in the case of, e.g., fireflies entraining to each others' flashes), it depends on voluntary control over, and voluntary or learned coupling of, sensory and motor systems, which can paradoxically lead to apparent failures of entrainment. Among the factors that affect whether an animal will entrain are sufficient control over the motor behavior to be entrained, sufficient perceptual sophistication to extract the entraining beat from the overall sensory environment, and the current cognitive state of the animal, including attention and motivation. The extent of entrainment in the animal kingdom potentially has widespread implications, not only for understanding the roots of human dance, but also for understanding the neural and cognitive architectures of animals.

The sound and the fury--bees hiss when expecting danger

Honey bees are important model systems for the investigation of learning and memory and for a better understanding of the neuronal basics of brain function. Honey bees also possess a rich repertoire of tones and sounds, from queen piping and quacking to worker hissing and buzzing. In this study, we tested whether the worker bees' sounds can be used as a measure of learning. We therefore conditioned honey bees aversively to odours in a walking arena and recorded both their sound production and their movement. Bees were presented with two odours, one of which was paired with an electric shock. Initially, the bees did not produce any sound upon odour presentation, but responded to the electric shock with a strong hissing response. After learning, many bees hissed at the presentation of the learned odour, while fewer bees hissed upon presentation of another odour. We also found that hissing and movement away from the conditioned odour are independent behaviours that can co-occur but do not necessarily do so. Our data suggest that hissing can be used as a readout for learning after olfactory conditioning, but that there are large individual differences between bees concerning their hissing reaction. The basis for this variability and the possible ecological relevance of the bees' hissing remain to be investigated.

Skinner's verbal behavior: A reference list

The language literature contains many citations to Skinner's book Verbal Behavior (1957), however, most of them are negative and generally unsupportive. The current list of references was assembled to bring readers in contact with the growing body of literature which supports Skinner's work. A total of 136 references were found and divided into two categories, (1) conceptual, and (2) experimental and applied. These references are presented in an effort to stimulate additional research in this important aspect of behavior analysis.

Quantified trends in the history of verbal behavior research

The history of scientific research about verbal behavior research, especially that based on Verbal Behavior (Skinner, 1957), can be assessed on the basis of a frequency and celeration analysis of the published and presented literature. In order to discover these quantified trends, a comprehensive bibliographical database was developed. Based on several literature searches, the bibliographic database included papers pertaining to verbal behavior that were published in the Journal of the Experimental Analysis of Behavior, the Journal of Applied Behavior Analysis, Behaviorism, The Behavior Analyst, and The Analysis of Verbal Behavior. A nonbehavioral journal, the Journal of Verbal Learning and Verbal Behavior was assessed as a nonexample comparison. The bibliographic database also included a listing of verbal behavior papers presented at the meetings of the Association for Behavior Analysis. Papers were added to the database if they (a) were about verbal behavior, (b) referenced B.F. Skinner's (1957) book Verbal Behavior, or (c) did both. Because the references indicated the year of publication or presentation, a count per year of them was measured. These yearly frequencies were plotted on Standard Celeration Charts. Once plotted, various celeration trends in the literature became visible, not the least of which was the greater quantity of verbal behavior research than is generally acknowledged. The data clearly show an acceleration of research across the past decade. The data also question the notion that a "paucity" of research based on Verbal Behavior currently exists. Explanations of the acceleration of verbal behavior research are suggested, and plausible reasons are offered as to why a relative lack of verbal behavior research extended through the mid 1960s to the latter 1970s.

Neurons controlling voluntary vocalization in the macaque ventral premotor cortex

The voluntary control of phonation is a crucial achievement in the evolution of speech. In humans, ventral premotor cortex (PMv) and Broca's area are known to be involved in voluntary phonation. In contrast, no neurophysiological data are available about the role of the oro-facial sector of nonhuman primates PMv in this function. In order to address this issue, we recorded PMv neurons from two monkeys trained to emit coo-calls. Results showed that a population of motor neurons specifically fire during vocalization. About two thirds of them discharged before sound onset, while the remaining were time-locked with it. The response of vocalization-selective neurons was present only during conditioned (voluntary) but not spontaneous (emotional) sound emission. These data suggest that the control of vocal production exerted by PMv neurons constitutes a newly emerging property in the monkey lineage, shedding light on the evolution of phonation-based communication from a nonhuman primate species.

Operant and nonoperant vocal responding in the mynah: Complex schedule control and deprivation-induced responding

Several recent studies have been concerned with operant responses that are also affected by nonoperant factors, (e.g., biological constraints, innate behavior patterns, respondent processes). The major reason for studying mynah vocal responding concerned the special relation of avian vocalizations to nonoperant emotional and reflexive systems. The research strategy was to evaluate operant and nonoperant control by comparing the schedule control obtained with the vocal response to that characteristic of the motor responses of other animals. We selected single, multiple, and chain schedules that ordinarily produce disparate response rates at predictable times. In multiple schedules with one component where vocal responding ("Awk") was reinforced with food (fixed-ratio or fixed-interval schedule) and one where the absence of vocal responding was reinforced (differential reinforcement of other behavior), response rates never exceeded 15 responses per minute, but clear schedule differences developed in response rate and pause time. Nonoperant vocal responding was evident when responding endured across 50 extinction sessions at 25% to 40% of the rate during reinforcement. The "enduring extinction responding" was largely deprivation induced, because the operant-level of naive mynahs under food deprivation was comparable in magnitude, but without deprivation the operant level was much lower. Food deprivation can induce vocal responding, but the relatively precise schedule control indicated that operant contingencies predominate when they are introduced.

Schedule control of the vocal behavior of Cebus monkeys

The vocal behavior of three Cebus monkeys was maintained by fixed-ratio schedules of response dependent reinforcement at values between fixed-ratio 1 and fixed-ratio 15. In one monkey that was exposed to variable-interval, fixed-interval, and conjunctive fixed-ratio fixed-interval schedules of reinforcement, vocal responding occurred at a low rate, but schedule-appropriate patterns were maintained. The rates and patterns of responding engendered indicated that the vocal operant can be brought under schedule control in the monkey by the use of response-dependent reinforcement.

Call usage learning in gray seals (Halichoerus grypus)

Call usage learning can be demonstrated on 4 different levels: signaling on command, signaling and refraining from signaling on command, responding to a trained stimulus with a signal from a specific signal class, and responding to the playback of any untrained stimulus with one from the same signal class. Two young gray seals (Halichoerus grypus) were trained successfully to demonstrate the first 2 levels. They also learned to respond to 9 moan stimuli and 9 growl stimuli with vocalizations of the same class (Level 3). However, novel moan and growl stimuli tended to elicit growls. This casts doubt on the possibility that gray seals can reach the 4th level, but it demonstrates that they are capable of the first 3 levels of usage learning.

Experimental analysis of human vocal behavior: applications of speech-recognition technology

Recent developments in speech recognition make it feasible to apply the technology to study vocal behavior. The present study illustrates the use of this technology to establish functional stimulus classes. Eight students were taught to say nonsense words in the presence of arbitrarily assigned sets of symbols consistent with three three-member experimenter-defined stimulus classes. Computer-controlled speech-recognition software was used to record, analyze, and differentially reinforce vocal responses. When the stimulus classes were established, students were taught to say a new nonsense word in the presence of one member of each stimulus class. Transfer of function was tested subsequently to determine if the novel stimulus names transferred to the remaining stimulus class members. Most subjects required two iterations of the training and testing procedures before transfer occurred. The data illustrate the usefulness of recording vocal behavior during stimulus control procedures and demonstrate the use of speech-recognition technology. The paper also describes the current state of speech-recognition technology and suggests several other areas of research that might benefit from using vocal behavior as its primary datum.

The different roles of social learning in vocal communication

While vocal learning has been studied extensively in birds and mammals, little effort has been made to define what exactly constitutes vocal learning and to classify the forms that it may take. We present such a theoretical framework for the study of social learning in vocal communication. We define different forms of social learning that affect communication and discuss the required methodology to show each one. We distinguish between contextual and production learning in animal communication. Contextual learning affects the behavioural context or serial position of a signal. It can affect both usage and comprehension. Production learning refers to instances where the signals themselves are modified in form as a result of experience with those of other individuals. Vocal learning is defined as production learning in the vocal domain. It can affect one or more of three systems: the respiratory, phonatory and filter systems. Each involves a different level of control over the sound production apparatus. We hypothesize that contextual learning and respiratory production learning preceded the evolution of phonatory and filter production learning. Each form of learning potentially increases the complexity of a communication system. We also found that unexpected genetic or environmental factors can have considerable effects on vocal behaviour in birds and mammals and are often more likely to cause changes or differences in vocalizations than investigators may assume. Finally, we discuss how production learning is used in innovation and invention, and present important future research questions. Copyright 2000 The Association for the Study of Animal Behaviour.

Operant control of vocal behavior in the cat

EVIDENCE OF OPERANT CONTROL OF VOCAL BEHAVIOR IN THE CAT IS PRESENTED: (1) On mult FR 12 S(Delta) schedule, cats miaowed rapidly during periods of S(D) and much less or not at all during S(Delta). (2) This control was re-established following reversal of stimuli. (3) The frequency distribution of response durations was shifted to both shorter and longer values by the differential reinforcement of shorter or longer response durations respectively. Since both the frequency and duration of vocal responses were shown to be under the control of the schedule of reinforcement, it is concluded that at least some of the vocal behavior of the cat is susceptible to operant control.

Vocalizations in the cat: behavioral methodology and spectrographic analysis

Attempts to understand the neural mechanisms underlying mammalian vocal behaviors, including speech, require study of the neural activity and anatomy of vocalization-controlling brain structures. Such studies necessitate the application of invasive neurobiological techniques in animal models. In the current study, cats are used in the development of an animal model of vocal tract control. The animals are instrumentally conditioned to vocalize for food reward. Acquisition of this task can occur within a few minutes, although additional training generally is required to solidly establish the behavior and to train subjects to produce consistently high rates of vocalization for prolonged periods of time. Following training, animals can generally sustain a rate of two calls per minute for a period of over two hours. Optimal task performance is partly dependent on motivation level. Although there is considerable variation between animals, the vocalizations produced have an average duration of 600 ms and a fundamental frequency of around 500 Hz. In addition, during a typical vocalization, there are dynamic variations of about 150 Hz for fundamental frequency and 17 dB for sound intensity. These variations provide opportunities for relating neural and muscular activity to different aspects of the vocal behavior they control. Based on a number of considerations, the model and techniques discussed here probably are most applicable to studying the neurobiology of sub-cortical nuclei subserving vocal control. Similar mechanisms might well be present in other species, including humans. Thus, data obtained from study of this model may be applicable to understanding the processes underlying vocal tract control during human speech.

Behavior modification of exessive noise in a young Basenji

Use of a bell contingent upon howling was mildly aversive to a young Basenji and led to decreased noise.

Shaping and discriminative control of underwater click vocalizations in a California Sea Lion

A captive vea lion (Zalophus californianus) which had never before produced clicking sounds in the laboratory was first conditioned to vocalize in air and subsequently learned to emit underwater clicks. clicking was brought under control by differential reinforcement procedures. Vocalization as an indicator response may be useful in the comparative study of discriminative behavior.

Can Animals Talk?

Speech is defined as operant vocal behavior reinforced through the mediation of other organisms. Attempts to control animal vocalizations by operant conditioning are therefore reviewed. Both laboratory studies and informal attempts are examined. Some evidence of successful control is found, and this evidence affords examples of genuine, if rudimentary, speech in animals. It is, therefore, concluded that man's capacity to talk is not a unique ability that demarcates him from the rest of the animal kingdom.