Odd But Yet Feasible MAO Procedures

In their review of this topic KEtC focus on vowel contrasts that have revealed directional asymmetries in infants and non-human animals. We offer some clarification with respect to these stimulus issues and highlight another aspect of this research landscape��the role of task demands��that must also guide future comparative investigations. Vowel perception asymmetries��stimulus issues The authors present a detailed overview of studies that reveal directional asymmetries in vowel discrimination in infants and several non-human species. To date infant perceptual asymmetries can be accounted for within the NRV framework (Polka and Bohn, 2011). Although directional asymmetries are evident for vowel pairs tested with cats, vervet monkeys, birds, and macaques, the overall pattern of the asymmetries observed in these SP600125 ic50 species is inconsistent with the predictions of the NRV model1. As KEtC note, contrast-specific comparisons are limited because very few contrasts have been tested with both animals and infants. However, the richest cross-species data set pertains to the /��-?/ contrast. For this contrast, infants show the asymmetry predicted by NRV (easier in the /��/ to /?/ direction) whereas cats, birds, and vervets show an asymmetry in the opposite direction. Macaques performed at ceiling in both directions. These findings point to distinct vowel discrimination patterns in human infants and non-human animals. Surprisingly, KEtC dismiss these findings and question whether the /��-?/ asymmetry in infants is interpretable. They further suggest that we have not claimed that infant perception of /��-?/ supports the NRV framework; this is an incorrect representation of our work. In Polka and Bohn (1996), which subsequently led to the formulation of the NRV framework, we report and discuss the /��-?/ asymmetry and propose an account based on the location of these vowels in the vowel space (/?/ is more extreme than /��/). We further propose how this peripherality effect is acoustically grounded in Polka and Bohn (2011, p. 474, paragraphs 6, 7): ��The salience and stability of natural referent vowels is due to formant frequency convergence or focalization. ��Focalization is graded and gives rise to salience differentials across the vowel space.�� To clarify, in all of the infant and animal experiments on the /��-?/ contrast to date, focalization differences are clearly observed; i.e., F1 and F2 are spectrally closer in the more peripheral vowel /?/ compared to the less peripheral /��/. Accordingly, there is no basis for viewing research on /��-ae/ as irrelevant to a discussion of comparative differences in vowel perception asymmetries. This issue aside, we concur with KEtC that the current literature is sparse and inadequate for drawing firm conclusions regarding species-specificity with respect to vowel perception asymmetries.