Verena R. Ohms, Paola Escudero, Karin Lammers & Carel ten Cate (2012): Zebra
finches and Dutch adults exhibit the same cue weighting bias in vowel
perception. Anim. Cogn. 15 (2), 155-161.
Abstract: Vocal tract resonances, called formants, are the most important
parameters in human speech production and perception. They encode linguistic
meaning and have been shown to be perceived by a wide range of species.
Songbirds are also sensitive to different formant patterns in human speech.
They can categorize words differing only in their vowels based on the
formant patterns independent of speaker identity in a way comparable to
humans. These results indicate that speech perception mechanisms are more
similar between songbirds and humans than realized before. One of the major
questions regarding formant perception concerns the weighting of different
formants in the speech signal (?acoustic cue weighting?) and whether this
process is unique to humans. Using an operant Go/NoGo design, we trained
zebra finches to discriminate syllables, whose vowels differed in their
first three formants. When subsequently tested with novel vowels, similar in
either their first formant or their second and third formants to the
familiar vowels, similarity in the higher formants was weighted much more
strongly than similarity in the lower formant. Thus, zebra finches indeed
exhibit a cue weighting bias. Interestingly, we also found that Dutch
speakers when tested with the same paradigm exhibit the same cue weighting
bias. This, together with earlier findings, supports the hypothesis that
human speech evolution might have exploited general properties of the
vertebrate auditory system.
URL: http://www.springerlink.com/content/45378645010m7x18/
For reprints please contact V.R. Ohms (email:
David Reby & Benjamin D. Charlton (2012): Attention grabbing in red deer
sexual calls. Anim. Cogn. 15 (2), 265-270.
Abstract: Identifying the respective functions of distinct call types is an
important step towards understanding the diversification of mammal vocal
repertoires. Red deer (Cervus elaphus) stags give two distinct types of
roars during the rut, termed ?common roars? and ?harsh roars?. This study
tests the hypothesis that harsh roars function to raise and maintain female
attention to calling males. To this end, we examined the response of female
red deer to playback sequences of common roar bouts including a bout of
harsh roars midway through the sequence. We found that females not only
substantially increased their attention to the bout of harsh roars but also
then maintained overall higher attention levels to subsequent common roar
bouts. Our results suggest that the specific acoustic characteristics of
male red deer harsh roar bouts may have evolved to engage and maintain the
attention of female receivers during the breeding season. More generally,
they indicate a possible evolutionary path for the diversification of male
sexual vocal repertoires.
URL: http://www.springerlink.com/content/21456060x5n63j26/
For reprints please contact David Reby (email:
Kind regards
Sonja
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Dr. Sonja Amoser
Steinrieglstraße 286
3400 Weidlingbach
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