A novel rater agreement methodology for language transcriptions: evidence from a nonhuman speaker

The ability to measure agreement between two independent observers is vital to any observational study. We use a unique situation, the calculation of inter-rater reliability for transcriptions of a parrot’s speech, to present a novel method of dealing with inter-rater reliability which we believe can be applied to situations in which speech from human subjects may be difficult to transcribe. Challenges encountered included (1) a sparse original agreement matrix which yielded an omnibus measure of inter-rater reliability, (2) “lopsided” 2×2 matrices (i.e. subsets) from the overall matrix and (3) categories used by the transcribers which could not be pre-determined. Our novel approach involved calculating reliability on two levels—that of the corpus and that of the above mentioned smaller subsets of data. Specifically, the technique included the “reverse engineering” of categories, the use of a “null” category when one rater observed a behavior and the other did not, and the use of Fisher’s Exact Test to calculate r -equivalent for the smaller paired subset comparisons. We hope this technique will be useful to those working in similar situations where speech may be difficult to transcribe, such as with small children

Context-related vocalizations in African grey parrots (Psittacus erithacus)

A few animal species are capable of vocal learning. Parrots are well known for their vocal imitation abilities. In this study, we investigated whether African grey parrots (Psittacus erithacus) emit specific vocalizations in specific contexts. We first described the vocal repertoire and its ontogenesis of four captive grey parrots. After a comparison with vocalizations emitted by wild and other captive African grey parrots, we observed that only three call categories were shared by all grey parrots populations, suggesting that isolated populations of parrots develop population-specific calls. Then, we artificially provoked ten different contexts and recorded vocalizations of four captive grey parrots in these situations. Parrots predominantly emitted call categories in some contexts: distress, protestation, alarm, asking (i.e. emitted when a bird wanted something from an experimenter and contact calls. These results suggest that some calls are learned and can be used in specific contexts

Higher-order semantic structures in an African Grey parrot\u27s vocalizations: Evidence from the Hyperspace Analog to Language (HAL) model

Previous research has described the significant role that social interaction plays in both the acquisition and use of speech by parrots. The current study analyzed the speech of one home-raised African Grey parrot (Psittacus erithacus erithacus) across three different social contexts: owner interacting with parrot in the same room, owner and parrot interacting out of view in adjacent rooms, and parrot home alone. The purpose was to determine the extent to which the subject’s speech reflected an understanding of the contextual substitutability (e.g., the word street can be substituted in context for the word road) of the vocalizations that comprised the units in her repertoire (i.e., global co-occurrence of repertoire units; Burgess in Behav Res Methods Instrum Comput 30:188–198, 1998; Lund and Burgess in Behav Res Methods Instrum Comput 28:203–208, 1996). This was accomplished via the human language model hyperspace analog to language (HAL). HAL is contextually driven and bootstraps language “rules” from input without human intervention. Because HAL does not require human tutelage, it provided an objective measure to empirically examine the parrot’s vocalizations. Results indicated that the subject’s vocalization patterns did contain global co-occurrence. The presence of this quality in this nonhuman’s speech may be strongly indicative of higher-order cognitive skills

Morphological and cellular aspects of tail and limb regeneration in lizards: a model system with implications for tissue regeneration in mammals

The present Review summarizes studies on the process of tissue regeneration of lizards, intended as amodel to understand the process of regeneration in amniote