Effect of avian-human joint attention on allospecific vocal learning by grey parrots (Psittacus erithacus)

Comparing the productive vocabularies of grey parrots (Psittacus erithacus) and young children

Due to their outstanding ability of vocal imitation, parrots are often kept as pets. Research has shown that they do not just repeat human words. They can use words purposefully to label objects, persons, and animals, and they can even use conversational phrases in appropriate contexts. So far, the structure of pet parrots' vocabularies and the difference between them and human vocabulary acquisition has been studied only in one individual. This study quantitatively analyses parrot and child vocabularies in a larger sample using a vocabulary coding method suitable for assessing the vocabulary structure in both species. We have explored the composition of word-like sounds produced by 21 grey parrots (Psittacus erithacus) kept as pets in Czech- or Slovak-speaking homes, and compared it to the composition of early productive vocabularies of 21 children acquiring Czech (aged 8-18 months), who were matched to the parrots by vocabulary size. The results show that the 'vocabularies' of talking grey parrots and children differ: children use significantly more object labels, activity and situation labels, and emotional expressions, while parrots produce significantly more conversational expressions, greetings, and multiword utterances in general. These differences could reflect a strong link between learning spoken words and understanding the underlying concepts, an ability seemingly unique to human children (and absent in parrots), but also different communicative goals of the two species.

Captive Blue-and-yellow macaws (Ara ararauna) show facial indicators of positive affect when reunited with their caregiver

In mammals, human-animal bonding is recognized as a source of positive affect for companion or farm animals. Because this remains unexplored in birds, we investigated captive parrots' perspective of the human-animal relationship. We used a classical separation-reunion paradigm and predicted that variations in parrots' facial displays and behaviours would indicate their appraisal of the relationship. The test was divided into three phases of two minutes each: the bird was placed in an unfamiliar environment with a familiar caregiver (union), then the bird was left alone (separation) and finally, the caregiver returned (reunion). The test was repeated 10 times for each bird and video recorded in order to analyze their behaviour. The data show significantly higher crown and nape feather heights, higher redness of the skin and higher frequency of contact-seeking behaviours during the union and reunion phases than during the separation phase during which they expressed long distance contact calls. We observed the expression of eye pinning during the union and reunion phases in one out of five macaws. We argue that variation in facial displays provides indicators of parrot's positive appraisal of the caretaker presence. Our results broaden the scope for further studies on parrots' expression of their subjective feelings.

A Review of the Model/Rival (M/R) Technique for Training Interspecies Communication and Its Use in Behavioral Research

In this paper, I will review the Model/Rival (M/R) technique that has been used to establish interspecies communication with Grey parrots (Psittacus erithacus). I will describe the original format developed by Todt, the relationship to other forms of observational learning outlined by other researchers, and the adaptations that I devised. I will describe how my undergraduate trainers and I isolated the various components that constitute the technique and explain how each is necessary, but how only the combination of all components is sufficient for successful implementation-and how improper implementation can lead to failure. I will briefly summarize the results of proper implementation-including the importance of interspecies communication itself as a technique for studying animal cognition.

Joint attention skills in wild Arabian babblers ( Turdoides squamiceps): a consequence of cooperative breeding?

Human cooperation strongly relies on the ability of interlocutors to coordinate each other's attentional state: joint attention. One predominant hypothesis postulates that this hallmark of the unique cognitive system of humans evolved due to the combination of an ape-like cognitive system and the prosocial motives that facilitate cooperative breeding. Here, we tested this hypothesis by investigating communicative interactions of a cooperatively breeding bird species, the Arabian babbler ( Turdoides squamiceps). The behaviour of 12 wild social groups was observed focusing on two distinct communicative behaviours: object presentation and babbler walk. The results showed that both behaviours fulfilled the criteria for first-order intentional communication and involved co-orientation of recipients' attention. In turn, recipients responded with cooperative and communicative acts that resulted in coordinated joint travel between interlocutors. These findings provide the first evidence that another animal species shows several key criteria traditionally used to infer joint attention in prelinguistic human infants. Furthermore, they emphasize the influence of cooperative breeding on sophisticated socio-cognitive performances, while questioning the necessity of an ape-like cognitive system underlying joint attentional behaviour.

Facial display and blushing: Means of visual communication in blue-and-yellow macaws (Ara Ararauna)?

Mainly recognized for their cognitive performance, the visual communication system and, particularly, the potential function of facial displays in parrots remain thus far unexplored. Here, we provide the first descriptive study of facial display use in captive blue-and-yellow macaws. We observed the feather position (sleeked or ruffled) on the crown, nape and cheek at the group level during the macaws' daily routine and individually while interacting with a familiar animal caretaker. In the latter context, blushing was also assessed on the bare skin of the cheek. Group level observations showed that crown, nape and cheek feathers ruffling was more frequent in activities requiring no locomotion than in activities requiring locomotion. With the animal caretaker, crown ruffling was significantly more frequent when the caretaker was actively engaging with the parrot than during a control phase with no mutual interaction. In addition, a significantly higher proportion of naïve observers judged blushing as being present on photographs taken during the mutual interaction phase than during the control phase. We thus showed significant variations in facial displays and bare skin colour based on the birds' social context and activity. Our results broaden the scope for further studies to determine whether parrots' faces provide visual social signals.

Use of experimenter-given cues in dogs

Since the observations of O. Pfungst the use of human-provided cues by animals has been well-known in the behavioural sciences ("Clever Hans effect"). It has recently been shown that rhesus monkeys (Macaca mulatta) are unable to use the direction of gazing by the experimenter as a cue for finding food, although after some training they learned to respond to pointing by hand. Direction of gaze is used by chimpanzees, however. Dogs (Canis familiaris) are believed to be sensitive to human gestural communication but their ability has never been formally tested. In three experiments we examined whether dogs can respond to cues given by humans. We found that dogs are able to utilize pointing, bowing, nodding, head-turning and glancing gestures of humans as cues for finding hidden food. Dogs were also able to generalize from one person (owner) to another familiar person (experimenter) in using the same gestures as cues. Baseline trials were run to test the possibility that odour cues alone could be responsible for the dogs' performance. During training individual performance showed limited variability, probably because some dogs already "knew" some of the cues from their earlier experiences with humans. We suggest that the phenomenon of dogs responding to cues given by humans is better analysed as a case of interspecific communication than in terms of discrimination learning.

Vocal learning in Grey parrots: A brief review of perception, production, and cross-species comparisons

This chapter briefly reviews what is known-and what remains to be understood-about Grey parrot vocal learning. I review Greys' physical capacities-issues of auditory perception and production-then discuss how these capacities are used in vocal learning and can be recruited for referential communication with humans. I discuss cross-species comparisons where applicable and conclude with a description of recent research that integrates issues of reference, production and perception.

Human Listeners Are Able to Classify Dog (Canis familiaris) Barks Recorded in Different Situations

The authors investigated whether human listeners could categorize played-back dog (Canis familiaris) barks recorded in various situations and associate them with emotional ratings. Prerecorded barks of a Hungarian herding dog breed (Mudi) provided the sample. Human listeners were asked to rate emotionality of the vocalization and to categorize the situations on the basis of alternative situations provided on a questionnaire. The authors found almost no effect of previous experience with the given dog breed or of owning a dog. Listeners were able to categorize bark situations high above chance level. Emotionality ratings for particular bark samples correlated with peak and fundamental frequency and interbark intervals. The authors did not find a significant effect of tonality (harmonic-to-noise ratio) on either the emotionality rating or situation categorization of the human listeners. Humans' ability to recognize meaning suggests that barks could serve as an effective means of communication between dog and human.

Ravens, Corvus corax, follow gaze direction of humans around obstacles

The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand-raised ravens not only visually co-orient with the look-ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co-orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub-adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed.

Cognitive and communicative capacities of Grey parrots — implications for the enrichment of many species

Much of my research has been devoted to determining the cognitive and communicative abilities of Grey parrots (Psittacus erithacus), but other companion animals and those in captivity in Zoos also have considerable capacities that are often under-utilised in such settings. Many such animals are left to their own devices for large parts of the day; their boredom may translate into unsuitable behaviour patterns. In order to address this problem, my colleagues and I began to devise various computer-based ‘toys’ that would not only provide enrichment in the sense of relieving boredom and reproducing situations somewhat like the challenges faced by animals in the wild on a daily basis, but also would help us determine the extent of these animals’ cognitive capacities. Some of these systems allow remote interactions between owners and their pets and others might be adapted for animal-animal interactions. In this paper I will describe these projects, their aims, and our limited progress.

Vocal learning in the Grey parrot (Psittacus erithacus): effects of species identity and number of trainers

Grey parrots (Psittacus erithacus) learn referential English labels when they view and interact with 2 humans who model vocal labeling and who demonstrate referentiality and functionality of a label (I.M. Pepperberg, 1990a). To test if both trainers are necessary, the authors contrasted 2-trainer modeling with training by 1 human who presented targeted labels to a bird in concert with appropriate items, who asked questions, and who would reward attempts at the label with the item. The bird was also tutored by either 1 or 2 interactive humans in conjunction with a conspecific who already used referential labels. Referential labels were learned from multiple live tutors but not a single trainer. Presence of a conspecific enhanced learning compared with single-trainer sessions but did not affect acquisition in 2-human sessions. Specific aspects of paired tutoring seem critical for acquiring referential vocal labels.

Evidence for a form of mutual exclusivity during label acquisition by grey parrots (Psittacus erithacus)?

The authors present context-dependent evidence for a form of mutual exclusivity during label learning by Grey parrots (Psittacus erithacus). For human children, mutual exclusivity refers to their assumption during early word learning that an object has one and only one label. Along with the whole-object assumption (that a label likely refers to an entire object rather than some partial aspect), mutual exclusivity is thought to guide children in initial label acquisition. It may also help children overcome the whole-object assumption by helping them interpret a novel word as something other than an object label, but for young children, any second label for an object can initially be more difficult to acquire than the first. The authors show that Grey parrots quickly learn object labels for items, then have considerable difficulty learning to use color labels with respect to a previously labeled item unless specifically taught to use a color and object label as a pair.

The eyes have it: the neuroethology, function and evolution of social gaze

Gaze is an important component of social interaction. The function, evolution and neurobiology of gaze processing are therefore of interest to a number of researchers. This review discusses the evolutionary role of social gaze in vertebrates (focusing on primates), and a hypothesis that this role has changed substantially for primates compared to other animals. This change may have been driven by morphological changes to the face and eyes of primates, limitations in the facial anatomy of other vertebrates, changes in the ecology of the environment in which primates live, and a necessity to communicate information about the environment, emotional and mental states. The eyes represent different levels of signal value depending on the status, disposition and emotional state of the sender and receiver of such signals. There are regions in the monkey and human brain which contain neurons that respond selectively to faces, bodies and eye gaze. The ability to follow another individual's gaze direction is affected in individuals with autism and other psychopathological disorders, and after particular localized brain lesions. The hypothesis that gaze following is "hard-wired" in the brain, and may be localized within a circuit linking the superior temporal sulcus, amygdala and orbitofrontal cortex is discussed.

Development of isolation-induced vocal behavior in normal-hearing and deafened guinea pig infants

Infants in many different animal species require auditory information from conspecifics to learn appropriate responses to important environmental and social cues. Isolation calls are emitted by infant guinea pigs in contexts of social separation from their mothers. The aim of the present study was to examine the ontogeny of the isolation calls in normal-hearing and deafened infant guinea pigs, from 2 to 40 days postpartum and to determine the role of hearing maternal vocalization in infant guinea pig vocal responses in contexts of social proximity and isolation. Female newborn pigmented guinea pigs (Cavia porcellus) were housed with their birth mother and siblings. Water and dry food were available ad libitum. One day postpartum, the cochlea of infants in the experimental group was destroyed. The control group consisted of normal-hearing female siblings. Vocalizations from infants in the experimental and control groups were recorded for 6 minutes when with the mother before isolation, 6 minutes when alone, and then 6 minutes when with the mother after reunion. Recordings were made 5 days per week from 2 to 40 days after birth. The duration of calling was calculated for each 6-minute period of recording. Results demonstrated that deaf infants vocalize more than normal-hearing infants during social isolation from their mothers. Vocal activity of isolated deaf and normal-hearing infants decreased substantially over development, almost disappearing by the end of the study period. These results indicate that maternal vocal behavior modulates the vocal responses of guinea pigs early in infant development and supports other evidence that the guinea pig offers a viable model for investigating audition in deaf and normal-hearing human infants.

Proposed use of two-part interactive modeling as a means to increase functional skills in children with a variety of disabilities

PURPOSE

Many behavior modification and intervention programs are based on operant procedures developed for animal subjects, but few use modeling procedures in which one student observes interactions between two proficient trainers. We show how such procedures, which successfully trained Grey parrots (Psittacus erithacus) to produce and comprehend elements of human language, can be adapted for use with children with three types of disabilities: (a) autism with limited social and language skills, (b) developmental delay with physical handicaps and lack of language skills, and (c) hyperactivity with impaired cognitive and social skills.

SUMMARY

Children were evaluated before entering the program and outcomes were recorded to determine improvement levels. No child reached totally normative (physical age-appropriate) levels, but all significantly improved their social and communication skills and use of contextually appropriate behavior.

CONCLUSIONS

A two-trainer modeling system can be a valuable intervention tool for children whose disabilities involve social and communicative skills.