Using network models of absolute pitch to compare frequency-range discriminations across avian species

The spectral frequency ranges of song notes are important for recognition in avian species tested in the field. Frequency-range discriminations in both the field and laboratory require absolute pitch (AP). AP is the ability to perceive pitches without an external referent. The authors provided a network model designed to account for differences in AP among avian species and evaluated it against discriminative performance in eight-frequency-range laboratory tests of AP for five species of songbirds and two species of nonsongbirds. The model's sensory component describes the neural substrate of avian auditory perception, and its associative component handles learning of the discrimination. Using only two free parameters to describe the selectivity and the sensitivity of each species’ auditory sensory filters, the model provided highly accurate predictions of frequency-range discrimination in songbirds and in a parrot species, but performance and its prediction were less accurate in pigeons: the only species tested that does not learn its vocalizations. Here for the first time, the authors present a model that predicted individual species’ performance in frequency-range discriminations and predicted differences in discrimination among avian species with high accuracy.     

Do musicians with perfect pitch have more autism traits than musicians without perfect pitch? An empirical study

Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increased prevalence of AP in individuals with sensory and developmental disorders. Here, we determine whether individual autistic traits are present in people with AP. We quantified subclinical levels of autism traits using the Autism-Spectrum Quotient (AQ) in three matched groups of subjects: 16 musicians with AP (APs), 18 musicians without AP (non-APs), and 16 non-musicians. In addition, we measured AP ability by a pitch identification test with sine wave tones and piano tones. We found a significantly higher degree of autism traits in APs than in non-APs and non-musicians, and autism scores were significantly correlated with pitch identification scores (r = .46, p = .003). However, our results showed that APs did not differ from non-APs on diagnostically crucial social and communicative domain scores and their total AQ scores were well below clinical thresholds for autism. Group differences emerged on the imagination and attention switching subscales of the AQ. Thus, whilst these findings do link AP with autism, they also show that AP ability is most strongly associated with personality traits that vary widely within the normal population.     

Absolute pitch: effects of timbre on note-naming ability

Background

Absolute pitch (AP) is the ability to identify or produce isolated musical tones. It is evident primarily among individuals who started music lessons in early childhood. Because AP requires memory for specific pitches as well as learned associations with verbal labels (i.e., note names), it represents a unique opportunity to study interactions in memory between linguistic and nonlinguistic information. One untested hypothesis is that the pitch of voices may be difficult for AP possessors to identify. A musician''s first instrument may also affect performance and extend the sensitive period for acquiring accurate AP.

Methods/Principal Findings

A large sample of AP possessors was recruited on-line. Participants were required to identity test tones presented in four different timbres: piano, pure tone, natural (sung) voice, and synthesized voice. Note-naming accuracy was better for non-vocal (piano and pure tones) than for vocal (natural and synthesized voices) test tones. This difference could not be attributed solely to vibrato (pitch variation), which was more pronounced in the natural voice than in the synthesized voice. Although starting music lessons by age 7 was associated with enhanced note-naming accuracy, equivalent abilities were evident among listeners who started music lessons on piano at a later age.

Conclusions/Significance

Because the human voice is inextricably linked to language and meaning, it may be processed automatically by voice-specific mechanisms that interfere with note naming among AP possessors. Lessons on piano or other fixed-pitch instruments appear to enhance AP abilities and to extend the sensitive period for exposure to music in order to develop accurate AP.     

Rats’ (Rattus norvegicus) temporal discrimination of brief auditory stimuli: How does it compare with that of humans (Homo sapiens) and zebra finches (Taeniopygia guttata)?

The present study with rats replicated an experiment on the ability of zebra finches and humans to discriminate among brief auditory stimuli (see Weisman et al., 1999, Experiment 2). We trained rats with 27 3-kHz tones that varied in duration from 10 ms to 1420 ms. Reinforcement was contingent on responding (approaching the food well) to the nine medium-durations range tones (56-255 ms) but not to the nine short-durations range (10-46 ms) or long-durations range tones (309-1420 ms). Rats also received post-discrimination transfer tests with 2 kHz and 4 kHz tones that varied over the same durations as the 3 kHz tones. Rats acquired the temporal discrimination to a slightly lower level of accuracy than seen in finches or humans by Weisman et al. (1999). We tested for transfer of the temporal discrimination to find that rats, similar to humans (data from Weisman et al., 1999), transferred to untrained 2-kHz and 4-kHz tones at levels approaching accuracy to that achieved to the trained 3-kHz tone. By contrast, zebra finches (data from Weisman et al., 1999) failed to transfer their discrimination to the trained tone. We conclude that (a) rats discriminate among tone durations at least as well as they do among auditory frequencies and (b) rats like humans, but unlike finches, are insensitive to absolute pitch in their temporal discrimination.     

Effects of early rearing experience on adult behavior and nesting in captive Hawaiian crows (Corvus hawaiiensis)

Behavioral data were collected during the breeding season on eight pairs of Hawaiian crows (Corvus hawaiiensis) housed at two facilities on different islands. All data were collected from videocamera time‐lapse recordings of the nesting platforms. Behaviors included frequency of nest cup manipulation, percent of time spent on nest, allopreening, play, and stereotypy. The number of breeding pairs increased from four in 1996 to six in 1997, to seven in 1998, and to eight in 1999. Five of the older birds (three males and two females) were solitary‐reared for most if not all of their first year, while the remaining 12 birds were all socially reared. Significant differences were found between isolate‐ and socially‐reared birds, with isolate‐reared birds having higher rates of solo play (P = 0.0041) and stereotypies (P = 0.0090). Pairs that were comprised of at least one isolate‐reared bird engaged in significantly less allopreening (P = <0.0001) than pairs in which both birds were socially reared. From 1996 to 1999, 87 eggs were laid, with a mean of 1.88 ± 0.24 SEM eggs per clutch. Only three females produced clutches every year, and they were responsible for 85.1% of the eggs laid. Although not significant, the mean number of clutches produced per pair decreased from 2.50 ± 0.65 in 1996 to 0.87 ± 0.99 in 1999. Age of females does not appear to be a critical factor in the decrease in clutch production. New pairing combinations are under way in an effort to improve propagation in this highly endangered species. Zoo Biol 21:59–75, 2002. © 2002 Wiley‐Liss, Inc.     

Vowel Identity between Note Labels Confuses Pitch Identification in Non-Absolute Pitch Possessors

The simplest and likeliest assumption concerning the cognitive bases of absolute pitch (AP) is that at its origin there is a particularly skilled function which matches the height of the perceived pitch to the verbal label of the musical tone. Since there is no difference in sound frequency resolution between AP and non-AP (NAP) musicians, the hypothesis of the present study is that the failure of NAP musicians in pitch identification relies mainly in an inability to retrieve the correct verbal label to be assigned to the perceived musical note. The primary hypothesis is that, when asked to identify tones, NAP musicians confuse the verbal labels to be attached to the stimulus on the basis of their phonetic content. Data from two AP tests are reported, in which subjects had to respond in the presence or in the absence of visually presented verbal note labels (fixed Do solmization). Results show that NAP musicians confuse more frequently notes having a similar vowel in the note label. They tend to confuse e.g. a 261 Hz tone (Do) more often with Sol than, e.g., with La. As a second goal, we wondered whether this effect is lateralized, i.e. whether one hemisphere is more responsible than the other in the confusion of notes with similar labels. This question was addressed by observing pitch identification during dichotic listening. Results showed that there is a right hemispheric disadvantage, in NAP but not AP musicians, in the retrieval of the verbal label to be assigned to the perceived pitch. The present results indicate that absolute pitch has strong verbal bases, at least from a cognitive point of view.     

Mechanisms of song production in the Australian magpie

Australian magpies (Gymnorhina tibicen) are notable for their vocal prowess. We investigated the syringeal and respiratory dynamics of vocalization by two 6-month-old males, whose songs had a number of adult features. There was no strong lateral syringeal dominance and unilateral phonation was most often achieved by closing the syringeal valve on the contralateral side of the syrinx. Unlike other songbirds studied, magpies sometimes used an alternative syringeal motor pattern during unilateral phonation in which both sides of the syrinx are partially adducted and open to airflow. Also, in contrast to most other songbirds, the higher fundamental frequency during two-voice syllables was usually generated on the left side of the syrinx. Amplitude modulation, a prominent feature of magpie song, was produced by linear or nonlinear interactions between different frequencies which may originate either on opposite sides of the syrinx or on the same side. Pulse tones, similar to vocal fry in human speech, were present in some calls. Unlike small songbirds, the fundamental of the modal frequency can be as low as that of the pulse tone, suggesting that large birds may have evolved pulse tones to increase acoustic diversity, rather than decrease the fundamental frequency.     

Development of the visual preference of chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) for photographs of primates: effect of social experience

In a study by Tanaka (2003) five captive chimpanzees preferred photographs of humans to those of chimpanzees. All the subjects were raised by humans and lived in captivity for many years. This suggests their preference might have developed through social experience. In this study examined this hypothesis by using three young chimpanzees raised by their mothers in a captive chimpanzee community. The young chimpanzees were tested four times before six years of age. I also tested eight adult chimpanzees that had been in captivity for more than 20 years. Each subject was presented with digitized color photographs of different species of primates on a touch-sensitive screen. The subjects received a food reward when they touched a photograph, irrespective of which photograph they touched. All the adult chimpanzees touched photographs of humans more frequently than those of any other species of primate. Two of the young chimpanzees showed no species preference before reaching 5 years of age, when they started to show preference for humans. The remaining young chimpanzee consistently preferred chimpanzees. These results suggest that development of visual preference of chimpanzees is affected by social experience during infancy.     

Familial aggregation of absolute pitch

Absolute pitch (AP) is a behavioral trait that is defined as the ability to identify the pitch of tones in the absence of a reference pitch. AP is an ideal phenotype for investigation of gene and environment interactions in the development of complex human behaviors. Individuals who score exceptionally well on formalized auditory tests of pitch perception are designated as "AP-1." As described in this report, auditory testing of siblings of AP-1 probands and of a control sample indicates that AP-1 aggregates in families. The implications of this finding for the mapping of loci for AP-1 predisposition are discussed.     

Comparison of auditory functions in the chimpanzee and human

Absolute thresholds for pure tones, loudness, frequency and intensity difference thresholds and the resonance of the external auditory meatus were measured in chimpanzees and compared with those in humans. Chimpanzees were more sensitive than humans to frequencies higher than 8 kHz but less sensitive to frequencies lower than 250 Hz and 2- to 4-kHz tones. Difference thresholds for frequency and intensity were greater in chimpanzees than in humans. The resonance of the external ear was about the same in the two species. The effects of differences in hearing between species upon speech perception are discussed.     

音乐绝对音高行为研究述评

音乐绝对音高(musical absolute pitch,AP)能力是一种敏锐的乐音音高知觉分类和记忆能力,表现为在没有任何其它音高参照的情况下,能够对所听到乐音音高进行准确命名或分类。本文从音乐绝对音高甄别方法、基因遗传、早期音乐训练、语言环境对音乐绝对音高能力形成的影响,以及绝对音高与音乐能力、音乐记忆和空间能力方面的研究进行了介绍,提出研究音乐绝对音高的重要性。最后展望了音乐绝对音高领域未来可能的四个研究方向。     

Effect of light and incubation temperature on production by species of Fusarium of metabolites toxic to larvae of Tenebrio molitor L

Larvae of Tenebrio molitor L., Gembloux strain, race F, having an initial weight of 10 mg were reared for 4 weeks at 27 +/- 0.25 degrees C 65 +/- 5% relative humidity on rye seed incubated with single isolates of four strains of Fusarium. The fungi had been cultured in total darkness or in constant light at a temperature of 8, 14, 20 or 24 degrees C. Two isolates of Fusarium poae (Peck). Wollenw. (7450 and 7452) retarded growth more than the third isolate of this species or than the isolate of Fusarium accuminatum Ell. & Ev. Nutritional value of rye seed decreased with increasing temperature, but declined to a larger extent when Fusarium species were present than when they were absent. The results suggest that changes in weight and mortality of larvae are good criteria for determining toxicity of fungal metabolites in Insects.     

Pitch enumeration: failure to subitize in audition

BACKGROUND: Subitizing involves recognition mechanisms that allow effortless enumeration of up to four visual objects, however despite ample resolution experimental data suggest that only one pitch can be reliably enumerated. This may be due to the grouping of tones according to harmonic relationships by recognition mechanisms prior to fine pitch processing. Poorer frequency resolution of auditory information available to recognition mechanisms may lead to unrelated tones being grouped, resulting in underestimation of pitch number. METHODS, RESULTS AND CONCLUSION: We tested whether pitch enumeration is better for chords of full harmonic complex tones, where grouping errors are less likely, than for complexes with fewer and less accurately tuned harmonics. Chords of low familiarity were used to mitigate the possibility that participants would recognize the chord itself and simply recall the number of pitches. We found that accuracy of pitch enumeration was less than the visual system overall, and underestimation of pitch number increased for stimuli containing fewer harmonics. We conclude that harmonically related tones are first grouped at the poorer frequency resolution of the auditory nerve, leading to poor enumeration of more than one pitch.     

Habituation of the eyeblink response in humans with stimuli presented in a sequence of incremental intensity

In an experiment we examined whether the repeated presentation of tones of gradually increasing intensities produces greater decrement in the eyeblink reflex response in humans than the repetition of tones of constant intensities. Two groups of participants matched for their initial level of response were exposed to 110 tones of 100-ms duration. For the participants in the incremental group, the tones increased from 60- to 90- dB in 3-dB steps, whereas participants in the constant group received the tones at a fixed 90-dB intensity. The results indicated that the level of response in the last block of 10 trials, in which both groups received 90-dB tones, was significantly lower in the incremental group than in the constant group. These findings support the data presented by Davis and Wagner (7) with the acoustic response in rats, but differ from several reports with autonomic responses in humans, where the advantage of the incremental condition has not been observed unambiguously. The discussion analyzes theoretical approaches to this phenomenon and the possible involvement of separate neural circuits.     

Human discrimination and modeling of high-frequency complex tones shed light on the neural codes for pitch

Accurate pitch perception of harmonic complex tones is widely believed to rely on temporal fine structure information conveyed by the precise phase-locked responses of auditory-nerve fibers. However, accurate pitch perception remains possible even when spectrally resolved harmonics are presented at frequencies beyond the putative limits of neural phase locking, and it is unclear whether residual temporal information, or a coarser rate-place code, underlies this ability. We addressed this question by measuring human pitch discrimination at low and high frequencies for harmonic complex tones, presented either in isolation or in the presence of concurrent complex-tone maskers. We found that concurrent complex-tone maskers impaired performance at both low and high frequencies, although the impairment introduced by adding maskers at high frequencies relative to low frequencies differed between the tested masker types. We then combined simulated auditory-nerve responses to our stimuli with ideal-observer analysis to quantify the extent to which performance was limited by peripheral factors. We found that the worsening of both frequency discrimination and F0 discrimination at high frequencies could be well accounted for (in relative terms) by optimal decoding of all available information at the level of the auditory nerve. A Python package is provided to reproduce these results, and to simulate responses to acoustic stimuli from the three previously published models of the human auditory nerve used in our analyses.     

The Development of Geographic Song Preferences in Female Song Sparrows Melospiza melodia

Previous work suggests that early learning plays a role in auditory preferences of female songbirds. We explored whether early experience shapes preferences for local geographic song in female song sparrows ( Melospiza melodia ), a species that prefers local geographic song in adulthood. We hand-reared females from two locations 450 km apart and controlled song exposure early in life. To examine the effects of experience and inherited factors on geographic song preferences, we used a counterbalanced design. Females from each location were tutored with either natal song (recorded from their location of capture) or non-natal song (recorded from the other location) and their preferences for tutor vs. non-tutor song assessed in adulthood. We also examined song preferences in isolate females reared with no song experience. We found that tutored females preferred their tutor song over non-tutor song, regardless of their capture location. Furthermore, birds not exposed to song (isolates) had no geographic song preferences. Thus, song exposure early in life clearly plays an important role in adult female preferences for local song in this species.     

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae)

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.     

Tonotypic cortical representation in man (case report)

Cortical stimulation--evoked perception of tones differing in pitch suggests that the perception of pitch may be discretely organized in the human auditory parakoniocortex. Findings, obtained from a neurosurgical patient undergoing temporal lobectomy, are discussed with reference to anatomical and functional considerations of the auditory parakoniocortex in humans. These tonotypic findings are potentially significant since, as previously reported, auditory sensations have not been analyzed in relation to perceptual categories of pitch.     

Circuits,hormones, and learning: Vocal behavior in songbirds

Species-typical vocal patterns subserve species identification and communication for individual organisms. Only a few groups of organisms learn the sounds used for vocal communication, including songbirds, humans, and cetaceans. Vocal learning in songbirds has come to serve as a model system for the study of brain-behavior relationships and neural mechanisms of learning and memory. Songbirds learn specific vocal patterns during a sensitive period of development via a complex assortment of neurobehavioral mechanisms. In many species of songbirds, the production of vocal behavior by adult males is used to defend territories and attract females, and both males and females must perceive vocal patterns and respond to them. In both juveniles and adults, specific types of auditory experience are necessary for initial song learning as well as the maintenance of stable song patterns. External sources of experience such as acoustic cues must be integrated with internal regulatory factors such as hormones, neurotransmitters, and cytokines for vocal patterns to be learned and produced. Thus, vocal behavior in songbirds is a culturally acquired trait that is regulated by multiple intrinsic as well as extrinsic factors. Here, we focus on functional relationships between circuitry and behavior in male songbirds. In that context, we consider in particular the influence of sex hormones on vocal behavior and its underlying circuitry, as well as the regulatory and functional mechanisms suggested by morphologic changes in the neural substrate for song control. We describe new data on the architecture of the song system that suggests strong similarities between the songbird vocal control system and neural circuits for memory, cognition, and use-dependent plasticity in the mammalian brain. © 1997 John Wiley & Sons, Inc. J Neurobiol 33: 602–618, 1997     

An evaluation of ERIC PCR and AP PCR fingerprinting for discriminating Salmonella serotypes

PCR fingerprints of 89 Salmonella isolates belonging to 22 serotypes were obtained using ERIC PCR (enterobacterial repetitive intergenic consensus PCR) and AP PCR (arbitrarily primed PCR) to evaluate the ability of different fingerprinting methods to differentiate or identify serotypes and subtypes. Fingerprints were scored and comparisons were made using a computer program. ERIC PCR produced a unique, complex fingerprint for almost every isolate, but these fingerprints did not identify serotypes. One AP PCR primer also produced complex fingerprints that discriminated among isolates, but again did not identify serotypes. A second AP PCR primer produced simple patterns, including one pattern shared by 35 isolates from 12 different serotypes. In general, the three sets of PCR fingerprints distinguished isolates, but were not correlated with serotypes. Matching fingerprints from different gels by computer was difficult, since similarities were based on both intense and faint bands. In addition, this study suggests that dendrograms created from PCR fingerprints should be viewed with caution.