Ulrike Griebel

Lateral asymmetry of eye use in Octopus vulgaris

The lateralization of sensory and motor functions has been recently demonstrated in various groups of vertebrates. We examined lateral asymmetry of eye use in Octopus vulgaris by behavioural methods. Octopus vulgaris uses monocular vision almost exclusively and can move its eyes independently. The amount of binocular vision is small because the eyes are on the sides of the head. We tested eight octopuses in two conditions (one with and one without moving stimuli) where the use of the eye for frontal vision could be determined unequivocally. Data were recorded on videotape. All animals showed a preference for one eye (five left, three right). There was no correlation between eye use and the animals direction of movement. Pigmentation of the ventral side of the arms tended to be most intense on the side of the preferred eye and the body was most pigmented on the side of the eye currently in use. We found no sex differences for visual lateralization. Pigmentation of the ventral side of the arms was lighter in females than in males. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Does Octopus vulgaris have preferred arms

Previous behavioral studies in Octopus vulgaris revealed lateralization of eye use. In this study, the authors expanded the scope to investigate arm preferences. The octopuss generalist hunting lifestyle and the structure of their arms suggest that these animals have no need to designate specific arms for specific tasks. However, octopuses also show behaviors, like exploration, in which only single or small groups of arms are involved. Here the authors show that octopuses had a strong preference for anterior arm use to reach for and explore objects, which points toward a task division between anterior and posterior arms. Four out of 8 subjects also showed a lateral bias. In addition, octopuses had a preference for a specific arm to reach into a T maze to retrieve a food reward. These findings give evidence for limb-specialization in an animal whose 8 arms were believed to be equipotential.

Vocabulary Learning in a Yorkshire Terrier: Slow Mapping of Spoken Words

Rapid vocabulary learning in children has been attributed to “fast mapping”, with new words often claimed to be learned through a single presentation. As reported in 2004 in Science a border collie (Rico) not only learned to identify more than 200 words, but fast mapped the new words, remembering meanings after just one presentation. Our research tests the fast mapping interpretation of the Science paper based on Ricos results, while extending the demonstration of large vocabulary recognition to a lap dog. We tested a Yorkshire terrier (Bailey) with the same procedures as Rico, illustrating that Bailey accurately retrieved randomly selected toys from a set of 117 on voice command of the owner. Second we tested her retrieval based on two additional voices, one male, one female, with different accents that had never been involved in her training, again showing she was capable of recognition by voice command. Third, we did both exclusion-based training of new items (toys she had never seen before with names she had never heard before) embedded in a set of known items, with subsequent retention tests designed as in the Rico experiment. After Bailey succeeded on exclusion and retention tests, a crucial evaluation of true mapping tested items previously successfully retrieved in exclusion and retention, but now pitted against each other in a two-choice task. Bailey failed on the true mapping task repeatedly, illustrating that the claim of fast mapping in Rico had not been proven, because no true mapping task had ever been conducted with him. It appears that the task called retention in the Rico study only demonstrated success in retrieval by a process of extended exclusion.

Spectral sensitivity and Color Vision in the Bottlenose Dolphin (Tursiops Truncatus)

Spectral sensitivity was measured in air in a bottlenose dolphin using a behavioral training technique. The spectral sensitivity curve shows two maxima in sensitivity, one in the near ultraviolet part of the spectrum and the other one in the bluegreen part at about 490 nm. Two wavelength discrimination tasks showed that the dolphin could discriminate two wavelengths from the peak regions of the two maxima of the spectral sensitivity function, but not between two wavelengths lying within the broad maximum of the curve in the bluegreen part of the spectrum. Possible underlying mechanisms for the shape of the function are discussed.

Brightness discrimination in the dog

Almost nothing is known about brightness discrimination in animals and how this ability relates to their lifestyles. As arrhythmic visual generalists, three dogs, a German shepherd and two Belgian shepherds, were tested on their ability to discriminate brightness using a series of 30 shades of grey varying from white to black. The dogs were trained to discriminate between different shades of grey in a simultaneous two-choice situation. Webers law can be correlated to their ability to discriminate brightness differences with a calculated Weber fraction of 0.22 for the German shepherd and 0.27 for the Belgian shepherds. Thus brightness discrimination in dogs is about 2 times worse than in humans, a diurnal species.

Squid dances: an ethogram of postures and actions of Sepioteuthis sepioidea squid with a muscular hydrostatic system

A taxonomy of the movement possibilities for any species, within the constraints of its neural and skeletal systems, should be one of the foundations of the study of its behaviour. Caribbean reef squid, Sepioteuthis sepioidea, appear to have many degrees of freedom in their movement as they live in a three-dimensional habitat and have no fixed skeleton but rather a muscular hydrostatic one. Within this apparent lack of constraints, there are regularities and patterns of common occurrences that allow this article to describe an ethogram of the movements, postures and positions of squid. Squid have a combination of bent, spread and twisted maintained postures of the eight arms and two tentacles that enhance camouflage. Their body–arm posture combinations are actively maintained in the water but also influenced by gravity. Positions related to conspecifics are stereotyped and important for communication. For locomotion, squid use a well-coordinated dual fin–jet locomotion system. This motor system uses tonic postures for camouflage and maintains body position in courtship, though squid seldom touch. The interdependence of movement control by different units is seen in fins and jet propulsion, and bilateral symmetry is maintained even for the eight arms. It is argued that the repertoire is well adapted for a soft-bodied animal in its three-dimensional, open but near-shore demersal habitat.

Developmental Plasticity and Language: A Comparative Perspective.

The growing field of evo-devo is increasingly demonstrating the complexity of steps involved in genetic, intracellular regulatory, and extracellular environmental control of the development of phenotypes. A key result of such work is an account for the remarkable plasticity of organismal form in many species based on relatively minor changes in regulation of highly conserved genes and genetic processes. Accounting for behavioral plasticity is of similar potential interest but has received far less attention. Of particular interest is plasticity in communication systems, where human language represents an ultimate target for research. The present paper considers plasticity of language capabilities in a comparative framework, focusing attention on examples of a remarkable fact: Whereas there exist design features of mature human language that have never been observed to occur in non-humans in the wild, many of these features can be developed to notable extents when non-humans are enculturated through human training (especially with intensive social interaction). These examples of enculturated developmental plasticity across extremely diverse taxa suggest, consistent with the evo-devo theme of highly conserved processes in evolution, that human language is founded in part on cognitive capabilities that are indeed ancient and that even modern humans show self-organized emergence of many language capabilities in the context of rich enculturation, built on the special social/ecological history of the hominin line. Human culture can thus be seen as a regulatory system encouraging language development in the context of a cognitive background with many highly conserved features.

Vocal Development as a Guide to Modeling the Evolution of Language

Modeling of evolution and development of language has principally utilized mature units of spoken language, phonemes and words, as both targets and inputs. This approach cannot address the earliest phases of development because young infants are unable to produce such language features. We argue that units of early vocal development-protophones and their primitive illocutionary/perlocutionary forces-should be targeted in evolutionary modeling because they suggest likely units of hominin vocalization/communication shortly after the split from the chimpanzee/bonobo lineage, and because early development of spontaneous vocal capability is a logically necessary step toward vocal language, a root capability without which other crucial steps toward vocal language capability are impossible. Modeling of language evolution/development must account for dynamic change in early communicative units of form/function across time. We argue for interactive contributions of sender/infants and receiver/caregivers in a feedback loop involving both development and evolution and propose to begin computational modeling at the hominin break from the primate communicative background.

New Frontiers in Language Evolution and Development

This article introduces the Special Issue and its focus on research in language evolution with emphasis on theory as well as computational and robotic modeling. A key theme is based on the growth of evolutionary developmental biology or evo-devo. The Special Issue consists of 13 articles organized in two sections: A) Theoretical foundations and B) Modeling and simulation studies. All the papers are interdisciplinary in nature, encompassing work in biological and linguistic foundations for the study of language evolution as well as a variety of computational and robotic modeling efforts shedding light on how language may be developed and may have evolved.