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Temporal Parameters (temporal + parameter)
Selected AbstractsDevelopment of learned flavor preferencesDEVELOPMENTAL PSYCHOBIOLOGY, Issue 5 2006Kevin P. Myers Abstract Rats, like humans, are born with only a few innate flavor preferences and aversions. Preferences retain great plasticity throughout the lifespan because they are sensitive to modification by experience. From an early age, rats can rapidly learn to prefer or avoid a flavor (conditioned stimulus, CS) that is associated with a positive or negative unconditioned stimulus (US). The US may be the mother's milk, social or thermotactile stimulation, or other food-related stimuli. Flavor-flavor learning occurs when the CS flavor is mixed with a naturally preferred (e.g., sweet) or avoided (e.g., bitter) US flavor. Flavor preferences and aversions are also produced by USs that have postoral positive (e.g., nutritious) or negative (e.g., toxic) actions. These types of learning appear to involve different behavioral and neural mechanisms as indicated by differences in conditioned responses, effective temporal parameters, resistance to extinction, and neurochemical mechanisms. New evidence indicates that flavor-nutrient preference learning can occur before weaning and influence food selection after weaning. Flavor conditioning not only affects food choice, but can also significantly increase food acceptance, that is, total consumption. Thus, from an early age, learning processes shape the feeding behavior of animals. While primarily serving an adaptive function, learning may play a role in biasing individuals towards excessive intake and weight gain. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 380,388, 2006. [source] Listening to language at birth: evidence for a bias for speech in neonatesDEVELOPMENTAL SCIENCE, Issue 2 2007Athena Vouloumanos The nature and origin of the human capacity for acquiring language is not yet fully understood. Here we uncover early roots of this capacity by demonstrating that humans are born with a preference for listening to speech. Human neonates adjusted their high amplitude sucking to preferentially listen to speech, compared with complex non-speech analogues that controlled for critical spectral and temporal parameters of speech. These results support the hypothesis that human infants begin language acquisition with a bias for listening to speech. The implications of these results for language and communication development are discussed. [source] Evolutionary significance of cranial variation in Asian Homo erectusAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2002Susan C. Antón Abstract Homo erectus inhabited a wide geographic area of Asia, ranging from 40° north latitude in China to 8° south latitude in island Southeast Asia. Yet variation within Asian H. erectus and its relation to ecological and temporal parameters have been little studied. I synthesize the revised radiometric chronologies for hominid sites in Asia and their relation to new oxygen isotope curves (proxies for climatic fluctuations and landbridge connections). These data suggest substantial opportunities in the later Pleistocene for both regional isolation and gene flow between hominids in mainland and Southeast Asia. They also suggest that the most northerly located Chinese sites (Zhoukoudian and Nanjing) may have been occupied during sequential, interglacial periods. Probably reflecting these periods of isolation, nonmetric features and principal components analysis (PCA) of calvarial shape suggest regional differentiation between northern Asian and Southeast Asian H. erectus. The most recent Southeast Asian fossils (e.g., Ngandong) conform to the Southeast Asian pattern. Except perhaps in brain size, there is no evidence that the temporally intermediate Chinese fossils are intermediate in morphology between older and younger Indonesian fossils. In fact, northern Chinese calvaria are easier to exclude from the larger Asian H. erectus hypodigm than are the Ngandong fossils. The Chinese specimens differ from the others based on their narrower occipitals and frontals for their cranial size. The Chinese sample from Zhoukoudian alone is thus not a good proxy for the morphology and variation seen within Asian H. erectus. Both the Chinese and late Indonesian samples exhibit less variation than does the early Indonesian sample; this along with their shared morphological bauplan suggests a common origin and no more than subspecific differentiation. This shared morphology, despite regional differences, was likely maintained by the increasing intensity of multiple glaciations (and longer-lasting land bridge connections) between mainland and island Southeast Asia during the last million years. Am J Phys Anthropol 118:301,323, 2002. © 2002 Wiley-Liss, Inc. [source] Geographic variation in loud calls of sportive lemurs (Lepilemur ssp.) and their implications for conservationAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2008Maria Méndez-Cárdenas Abstract Bioacoustical studies in nonhuman primates have shown that loud calls can be reliably used as a noninvasive diagnostic tool for discriminating cryptic taxa, for their monitoring in the field as well as for the reconstruction of their phylogeny. To date, it is unknown, whether loud calls can be used for these purposes in sportive lemurs, for which current genetic studies suggest the existence of at least 24 cryptic species. The aim of this study was to compare the structure of loud calls of populations of sportive lemurs to characterize informative acoustic traits for taxa discrimination and to establish a phylogenetic tree based on acoustic structure. We have based our study on Inter-River-Systems (IRSs) as operational taxonomic units. Samples were collected from nine different localities of four IRSs along a transect from northwestern to northern Madagascar. Two call types, the ouah and the high-pitched call, were present in almost all IRSs. Six temporal and eight spectral parameters were measured in 196 calls of the best quality given by 21 different males. Variation within and between IRSs was assessed by multivariate statistics. Loud calls differed significantly among the different IRSs. The IRSs varied most in spectral parameters, whereas temporal parameters were less variable. Phylogenetic analysis using parsimony yielded 11 out of 17 acoustic characters as phylogenetically informative. The acoustic tree had an average branch support of 78%. Its topology coincided less with geographic distances than with genetic tree topology. Altogether our findings revealed that loud calls separated geographically isolated populations of sportive lemurs specifically. Based on these results, noninvasive tools for diagnosis and monitoring of cryptic species in nature can be developed for conservation management. Am. J. Primatol. 70:828,838, 2008. © 2008 Wiley-Liss, Inc. [source] Voice variance may signify ongoing divergence among black-legged kittiwake populationsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2009HERVE MULARD Acoustic features are important for individual and species recognition. However, while dialectal variations in song characteristics have been described in many songbirds, geographical divergence in vocal features across populations has seldom been studied in birds that are not thought to have song-learning abilities. Here, we document marked differences in the vocal structure of calls of two populations of black-legged kittiwakes (Rissa tridactyla), a seabird whose call is considered as not being learned from other individuals. We found that calls vary both within and between populations. Within-population variation may convey individual identity, whereas the marked differences in frequency and temporal parameters observed between the two populations may reveal ongoing divergence among kittiwake populations. Moreover, we were unable to detect any sex signature in adult calls in a Pacific population (Middleton, Alaska), while these were detected in an Atlantic population (Hornøya, Norway), potentially affecting sexual behaviours. Despite the fact that these calls seemed to change over the reproductive season and across years, the individual signature remained fairly stable. Such vocal differences suggest that Pacific and Atlantic populations may be undergoing behavioural divergences that may reveal early stages of speciation, as is suggested by molecular data. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 289,297. [source] | ||||||||||