Previous studies have suggested that female voices may impede verbal processing. For example, words were remembered less well and lexical decision was slower when spoken by a female speaker. The... Show morePrevious studies have suggested that female voices may impede verbal processing. For example, words were remembered less well and lexical decision was slower when spoken by a female speaker. The current study tried to replicate this gender effect in an auditory semantic/associative priming task that excluded any effects of speaker variability and extended previous research by examining the role of two voice features important in perceived gender: pitch and formant frequencies. Additionally, listener gender was included in the experimental design. Results show that, contrary to previous findings, there is no evidence that a lexical decision of a target word is slower when spoken by a female speaker than by a male speaker for female and male listeners. Additionally, the semantic/associative priming effect was not affected by speaker gender, neither did female mean pitch or formants predict the semantic/associative priming effect. At the behavioural level, the current study found no evidence for a gender effect in a semantic/associative priming task. Show less
Birdsong and human speech are both complex behaviours which show striking similarities mainly thought to be present in the area of development and learning. The most important parameters in human... Show moreBirdsong and human speech are both complex behaviours which show striking similarities mainly thought to be present in the area of development and learning. The most important parameters in human speech are vocal tract resonances, called formants. Different formant patterns characterize different vowels and are produced by moving articulators such as tongue and lips. However, not much is known about the production and perception of vocal tract resonances by birds. In this thesis I show that both songbirds and parrots use different articulators, comparable to humans, to modify the sound produced. While in songbirds beak gape and the expansion of the oropharyngeal-esophageal cavity are the most important articulators, parrots exhibit prominent tongue movements which also might explain their sophisticated ability to mimic human speech. Regarding formant perception I show that zebra finches can discriminate human words differing only in their vowels and categorize these words independent of speaker identity. To do so the birds employ, just like humans, a combination of intrinsic and extrinsic speaker normalization. Furthermore, when tested for a cue weighting bias both zebra finches and Dutch adults weight higher frequencies stronger. These results indicate that the mechanisms underlying vocal production and perception in birds and humans exhibit more similarities than realized before and studying birdsong will increase our knowledge about the emergence of these mechanisms and might even shed light on the evolution of human speech. Show less
