Human speech and birdsong have numerous parallels. Both humans and songbirds learn their complex vocalizations early in life, exhibiting a strong dependence on hearing the adults they will imitate, as well as themselves as they practice, and a waning of this dependence as they mature. Innate predispositions for perceiving and learning the correct sounds exist in both groups, although more evidence of innate descriptions of species-specific signals exists in songbirds, where numerous species of vocal learners have been compared. Humans also share with songbirds an early phase of learning that is primarily perceptual, which then serves to guide later vocal production. Both humans and songbirds have evolved a complex hierarchy of specialized forebrain areas in which motor and auditory centers interact closely, and which control the lower vocal motor areas also found in nonlearners. In both these vocal learners, however, how auditory feedback of self is processed in these brain areas is surprisingly unclear. Finally, humans and songbirds have similar critical periods for vocal learning, with a much greater ability to learn early in life. In both groups, the capacity for late vocal learning may be decreased by the act of learning itself, as well as by biological factors such as the hormones of puberty. Although some features of birdsong and speech are clearly not analogous, such as the capacity of language for meaning, abstraction, and flexible associations, there are striking similarities in how sensory experience is internalized and used to shape vocal outputs, and how learning is enhanced during a critical period of development. Similar neural mechanisms may therefore be involved.

/pdf/birdsong-and-human-speech-common-themes-and-mechanisms-39gg3m47d4.pdf

BIRDSONG AND HUMAN SPEECH: Common Themes and Mechanisms

A precursor of language acquisition in young infants.

Surveying the terrain a brief historical perspective on language acquisition research early research on speech perception how speech perception develops in the first year the role of memory and attentional processes in the development of speech perception how attention to sound properties may facilitate learning other elements of linguistic organization relating perception to production wrapping things up. Appendix - methodology used in studies of infant speech perception.

https://www.gendocs.ru/docs/18/17604/conv_1/file1.pdf

The discovery of spoken language

Evidence from fields as diverse as cognitive, evolutionary, and developmental psychology, as well as cognitive neuroscience, has increasingly pointed to the ‘special’ nature of face recognition. A critical examination of the literature supports the view that faces begin to be seen as a separate class of objects within the first 6 months of life. Not surprisingly, the neural systems that underlie face recognition also come on line during this period of time. Less clear, however, are the mechanisms whereby these events occur. It seems likely that face recognition reflects an experience-expectant process, whereby exposure to faces during a sensitive period of development likely leads to perceptual and cortical specialization. However, it is unknown what the role of experience is in maintaining this ability, and how long this sensitive period lasts. After reviewing three related models that attempt to account for the way the ability to recognize faces develops, a number of suggestions are offered for testing the hypothesis that face recognition depends on experience for acquisition, and for evaluating the role of experience in maintaining this ability. Copyright © 2001 John Wiley & Sons, Ltd.

https://www.biac.duke.edu/education/courses/spring03/cogdev/readings/C.A.%20Nelson%20(2001).pdf

The Development and Neural Bases of Face Recognition

Integration of information from face and voice plays a central role in our social interactions. It has been mostly studied in the context of audiovisual speech perception: integration of affective or identity information has received comparatively little scientific attention. Here, we review behavioural and neuroimaging studies of face-voice integration in the context of person perception. Clear evidence for interference between facial and vocal information has been observed during affect recognition or identity processing. Integration effects on cerebral activity are apparent both at the level of heteromodal cortical regions of convergence, particularly bilateral posterior superior temporal sulcus (pSTS), and at 'unimodal' levels of sensory processing. Whether the latter reflects feedback mechanisms or direct crosstalk between auditory and visual cortices is as yet unclear.

Integrating Face and Voice in Person Perception

it was reduced below and above this frequency and at higher frequencies remained at about 20 dB up to the highest recorded, 5 kHz. The amount of attenuation fluctuated, however: conversation at normal levels outside the animal could often, but not always, be understood when transmitted from inside. Raised voices were almost always distinct. Sounds generated within the ewe herself were picked up by the implanted hydrophone, amplified, and recorded by a tape recorder or fed directly to the spectrum analyzer (as the amplifier had two outputs we were able to listen while analyzing the sounds). In the main, sounds heard were characteristic and identifiable: drinking, eating, swallowing, rumination, and sometimes heavy breathing could be heard. Rumination, unexpectedly, was rather quiet. A rushing sound sometimes accompanied movement by the ewe and irregular gurgles, probably of digestive origin, occurred frequently. Periods of quiet were not unusual. Figure 2 shows root mean square values at peaks taken from spectrum analyses, for different types of internal sound. These were of low frequency, tailing off above 500 Hz. Although we found attenuation of external sounds to be less than in other species (2, 3, 6), the loudness peaks and frequency of internal sounds were similar to those recorded by others (3, 6). However, average sound levels were lower than those previously reported (2, 3, 6, 7), especially as we often observed periods of quiet. In one particular our results were at variance with those of other workers: we were not able to hear sounds from the maternal cardiovascular system. By holding a hydrophone firmly against the ewe's skin in the brachial area we were able to pick up heart

Of Human Bonding: Newborns Prefer Their Mothers' Voices

Hydrophones implanted inside the intact amniotic sac recorded sounds available to fetal lambs. Unlike recordings made from outside the intact amnion in human subjects, sounds produced at levels similar to normal conversation from outside the ewe were picked up without masking by maternal cardiovascular sounds. Noises from inside the mother were intermittent and linked to her activity.

https://science.sciencemag.org/content/sci/208/4448/1173.full.pdf

The fetal sound environment of sheep.

The sound environment of the foetal lamb was recorded using a hydrophone implanted a few weeks before term in a small number of pregnant ewes. It was implanted inside the amniotic sac and sutured loosely to the foetal neck, to move with the foetus. Results differ from those reported earlier for the human foetus: sounds from the maternal cardiovascular system were picked up only rarely, at very low frequencies and at sound pressures around, or below, the human auditory threshold. Other sounds from within the mother occurred intermittently and rose to a high sound pressure only at frequencies above about 300 Hz. Sounds from outside the mother were picked up by the implanted hydrophone when the external sound level rose above 65-70 dB SPL, and the attenuation in sound pressure was rarely more than 30 dB and, especially at low frequencies, usually much less. However, attenuation due to the transmission of sound through the body wall and other tissues tended to change from time to time. It is concluded that the foetal lamb's sound environment consists of (1) intermittent low frequency sounds associated largely with the ewe's feeding and digestive processes and (2) sounds such as vocalisations from the flock, human voices and other sounds from outside the mother.

B. A. Baldwin

Papers

Of Human Bonding: Newborns Prefer Their Mothers' Voices

The fetal sound environment of sheep.

The Sound Environment of the Foetal Sheep