Temporal summation in the European starling (Sturnus vulgaris).

Temporal summation was studied in the European starling (Sturnus vulgaris) by using operant conditioning and the psychophysical method of constant stimuli. Auditory thresholds in quiet were determined for tones of 500; 1,000; 2,000; and 4,000 Hz with durations of between 30 and 2,000 ms, and temporal-summation functions were generated from the threshold data. Integration times depended on frequency; the shortest integration times were found at 500 and 4,000 Hz, and the longest at 1,000 and 2,000 Hz. The slopes of the temporal-summation functions at 1,000 and 2,000 Hz indicate a complete summation of energy. Temporal summation is discussed with respect to comparative data from other vertebrates and the possible neurophysiological mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative pitch perception in the European starling (Sturnus vulgaris): Further evidence for an elusive phenomenon.

Relative pitch perception in animals has been difficult to demonstrate. This failing is due in part to stimulus sets that make an absolute pitch solution viable. In Experiment 1, starlings failed to acquire a discrimination that could be solved only on the basis of relative pitch. In Experiment 2, starlings were trained on a smaller set of pitch patterns, for which both absolute and relative pitch solutions were available, then tested with three series of unreinforced probe stimuli. Series 1 assessed stimulus control by absolute pitch. In Series 2, absolute pitch cues dictated one response, and relative pitch cues dictated a different response. Results indicate that starlings extract relative pitch from artificial pitch patterns only after acquiring a discrimination that permits both absolute and relative pitch solutions. Results are discussed in terms of the relative salience of absolute and relative pitch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concurrent absolute and relative pitch processing by European starlings (Sturnus vulgaris).

In responding to sounds, birds use both relative and absolute pitch perception. As a means of testing which type of pitch perception is dominant, European starlings (Sturnus vulgaris) were trained to discriminate between low-ascending and high-descending sequences of tones. They were then tested with high-ascending and low-descending sequences during probe and transfer sessions. The birds could transfer their discrimination on the basis of either high versus low (absolute pitch) or ascending versus descending (relative pitch). During probe sessions, birds responded to nonreinforced novel sequences on the basis of absolute pitch. However, during transfer sessions, the birds could quickly learn to respond to reinforced novel sequences on the basis of relative pitch. The results indicate that during initial training, the birds learned about both relative and absolute aspects of the stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory frequency generalization and a failure to find octave generalization in a songbird, the European starling (Sturnus vulgaris).

Examined frequency generalization in starlings (Sturnus vulgaris) that were trained to discriminate between individual frequencies. Starlings were tested for frequency generalization after training on 2- and 3-tone discriminations. There was no evidence for octave generalization, which is a hallmark of human absolute pitch perception. This suggests that avian absolute pitch perception must not be interpreted as identical with that in humans. A control experiment with 1-tone discriminations indicated that the presence of lit response keys affect the shape of the generalization gradients. Lit response keys are a common feature in avian auditory perception experiments, and this control experiment cautions that results may be affected by this seemingly minor procedural change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory discrimination of chord-based spectral structures by European starlings (Sturnus vulgaris).

European starlings (Sturnus vulgaris) were trained to discriminate two complex harmonic structures modeled after musical chords in a 2-alternative choice task. Musical chords provide rich acoustic structures with which to study relative pitch perception and perceptual invariance in nonhuman animals. The starlings learned the chord discrimination and transferred the discrimination to chords with different root frequencies, thus showing perceptual invariance for the chords. Further transfer tests showed that correlates of chord structure were indeed controlling discrimination performance. The proposition that the starlings were responding primarily to a sensory dimension of consonance and dissonance in the acoustic structures provides a good account of the data. The harmonic principles that govern consonance and dissonance may be important for starling auditory communication and, perhaps, auditory communication of other songbirds. From the standpoint of human music cognition, the data add to previous observations suggesting that the idea of musical universals may be extended to species other than humans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A psychophysical measure of pitch discrimination loss resulting from a frequency range constraint in European starlings (Sturnus vulgaris).

Earlier research by the 1st and 2nd authors (see record 1986-08273-001) revealed that a number of species of songbirds acquired a pitch discrimination between rising and falling sequences in an arbitrarily defined training range of frequencies but then failed to generalize the discrimination to new frequency ranges—a frequency range constraint. The present 2 experiments with 3 adult European starlings provide a psychophysical estimate of how pitch discrimination deteriorated in this species as sequences were stepped out from the training range. Results show that the gradient showing loss of discrimination was much sharper than would have been anticipated by stimulus generalization or the training procedures and appeared unaffected by the removal of rising and falling frequency information. It is concluded that the frequency range constraint and its psychophysical properties have implications both for the analysis of birdsong and the study of animal cognition. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer of serial stimulus relations by European starlings (Sturnus vulgaris): Loudness.

Four experiments investigated the ability of European starlings (Sturnus vulgaris) to perceive stimulus relations in serial sound patterns. Loudness was the relevant stimulus dimension. In Exp 1, Ss learned to discriminate between patterns of sine tones that increased and decreased monotonically in loudness. The discrimination transferred successfully to novel loudness levels outside the baseline training range. Starlings also maintained the discrimination when the loudness intervals between successive pattern elements were doubled in Exp 2 and when frequency was shifted in Exp 4. Successful discrimination was directly contingent on stimulus relations (i.e., increasing vs decreasing loudness levels) in Exp 3. When loudness relations were removed, the discrimination was lost. The research shows that the birds used stimulus relations as the basis for serial pattern discrimination. These results contrast with the results of earlier work on serial pitch-pattern discriminations in which birds attended preferentially to absolute as compared with relational features to guide performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Song sharing reflects the social organization in a captive group of European starlings (Sturnus vulgaris).

The social organization of captive groups of adult male and female starlings caught in different localities was studied to understand the possible social basis of song sharing. In the nonbreeding season, the social organization was based on within-sex groups or pairs and a few intersexual pairs. The pattern of song sharing clearly reflected the social organization. Members of the social pairs of females shared most of their songs, whereas males shared songs with other males to an extent that depended on their degree of social association. Song sharing was mostly restricted to birds of the same sex. The ability for adult vocal plasticity in both males and females may reflect the variety of possible social situations in this species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult:young ratio influences song acquisition in female European starlings (Sturnus vulgaris).

One parallel between humans and most songbirds is the fact that young require social interactions with an adult to acquire specific vocalizations. Songbirds are considered good models for comparative studies, although reports to date concern almost exclusively male songbirds. In addition, adult influence on vocal communication is generally investigated only in restricted social contexts (usually dyads). Here, the authors analyzed song learning and spatial associations among young female starlings that were maintained for 1 year in dyads (1 adult, 1 young), triads (2 adults, 1 young) or a larger group (7 young, 2 adults). Segregation by age was seen in the triads and in the larger group. The influence of adults (proportion of songs copied from adults) decreased as the young adult ratio increased. Unusual temporal features were observed in young maintained in triads and young neglected copying adult songs in the presence of peers. These results are among the first to explore the circumstances under which females learn and from whom they learn. They also add new insight to a wide range of questions about social influences on learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory scene analysis by songbirds: Stream segregation of birdsong by European starlings (Sturnus vulgaris).

Three experiments examined the capacity of European starlings to segregate perceptually 2 superimposed, intermixed auditory stimuli. The stimuli were 10-s song samples from 2 of 4 songbird species: European starling, brown thrasher, mockingbird, and nightingale. The birds first learned a discrimination between the intermixed song pairs. Then, they maintained the discrimination with novel song exemplars in the mixtures and when song stimuli for each species were presented alone. Performance fell, but remained above chance, when song pairs were mixed with the dawn chorus of bird song. The results show that starlings were identifying the songs of individual species within the baseline superimposed song pairs, a process of auditory stream segregation and scene analysis (A. S. Bregman, 1990). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of missing fundamental by a species of songbird (Sturnus vulgaris).

Two experiments investigated whether a species of songbird, the European starling, perceives missing fundamentals in sounds containing complex frequencies. In Exp I, 3 Ss were trained to discriminate between 2 sinusoids. This discrimination persisted when the sinusoids were replaced with waveforms composed solely of 4 consecutive higher harmonics of the training frequencies. In Exp II, 6 Ss trained to discriminate between 2 complex frequencies consisting of sets of higher harmonics transferred the discrimination to the sinusoidal fundamentals. It is suggested that starlings can perceive harmonic or periodic structure and that a species of songbird can use harmonic structure to gain information about its auditory environment. The findings, together with those obtained from fish and mammals, suggest that periodicity pitch perception may be a general process in vertebrate hearing. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for Opioid Involvement in the Regulation of Song Production in Male European Starlings (Sturnus vulgaris).

Many social animals vocalize at high rates, suggesting that vocal communication is highly motivated and rewarding. In songbirds, much is known about the neural control of vocal behavior; however, little is known about neurobiological mechanisms regulating the motivation to communicate. This study examined a possible role for opioid neuropeptides in motivation and reward associated with song production in male European starlings (Sturnus vulgaris). Peripheral opioid blockade facilitated male song production. Furthermore, methionine-enkephalin immunolabeled fiber densities within brain regions in which opioids are known to regulate motivation and reward (i.e., the medial preoptic nucleus and ventral tegmental area) related positively to male song production. These data suggest that song production might be regulated by opioid activity within motivation and reward neural systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Avfail in color avoidance learning by starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus).

Certain unconditioned stimulus/stimuli (UCS) in flavor avoidance learning sometime become ineffective after pairings with relatively stronger UCS. This failure of avoidance learning (avfail) has been demonstrated only with rodents. The present investigations examined whether avfail might also occur with avian species, the food selection of which is guided primarily by visual cues. In Exp I, 20 male starlings were given pairings of 2 mg/kg methiocarb (a relatively weak UCS) and LiCl (a relatively strong UCS) in propylene glycol vehicle. In Exp II, 20 male red-winged blackbirds were given pairings of 2 or 4 mg/kg methiocarb (relatively weak and relatively strong UCS, respectively). Pairings were followed by a conditioning trial (UCS gavage in the presence of a color cue) and 2-choice tests. Conditioned avoidance was observed except (a) when methiocarb preceded LiCl and (b) when the low preceded the high methiocarb dose in preconditioning pairings. Exp III, with 20 Ss of each species, demonstrated that UCS habituation could not account for the results of Exps I and II. The data reflect avfail in the visual modality, and a biological implication of the results is that birds may not learn strong avoidance of aposematic prey containing varied levels of toxicant. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social Suppression of Song Is Associated With a Reduction in Volume of a Song-Control Nucleus in European Starlings (Sturnus vulgaris).

In seasonally breeding songbirds, variations in testosterone and song correlate with volume changes in brain nuclei associated with song, including the HVC. The authors tested whether singing can lead to activity-dependent increases in HVC volume by examining song output in starlings (Sturnus vulgaris). The authors manipulated males' environments so that only some were dominant with nestboxes, whereas others were not. Some of these males thus sang at higher rates and had larger HVC volume than others. The study was conducted over 2 years. In 1 year, males selectively occupied nestboxes but did not sing. HVC volume did not differ in these starlings, indicating that nestbox possession alone cannot increase HVC. The findings suggest that changes in song nuclei volume can be driven by changes in singing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric Specialization in the Primary Auditory Area of Awake and Anesthetized Starlings (Sturnus vulgaris).

Although evidence exists for a lateralization of song production, few studies have focused on the perceptual aspect of lateralization in songbirds. In the present study, the authors recorded neuronal responses to a variety of species-specific and artificial, nonspecific stimuli in both hemispheres of awake and anesthetized male starlings (Sturnus vulgaris). Recordings were made in the primary auditory area of the songbird brain, the Field L complex. The right hemisphere exhibited significantly more responsive units than the left hemisphere in awake birds, and this difference was significantly reduced in anesthetized birds. Furthermore, clear hemispheric specialization toward categories of behaviorally relevant stimuli and precise parameters of these stimuli were found. The main auditory area of the starling's brain thus appears to show some degree of lateralization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of cliff swallow calls by birds (Hirundo pyrrhonota and Sturnus vulgaris) and humans (Homo sapiens).

Tested for species differences in the perception of the cliff swallow chick begging call. One cliff swallow, 3 European starling, and 3 human Ss were trained on go–no-go or repeating background tasks to discriminate between all possible stimulus pairs, measured by percentage of correct response and latency. Multidimensional scaling was used to convert the similarity measures into a 2-dimensional map for each S. Most of the maps were significantly correlated in Dimension 1 but not in Dimension 2. A cluster analysis separated bird and human maps. To identify the most important acoustic cues for each S, the coordinates of each dimension were regressed on acoustic variables measured from the stimuli. For all Ss, center frequency was Dimension 1. Different acoustic cues were associated with Dimension 2, with agreement only on bandwidth, by the cliff swallow and 1 starling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative pitch perception is constrained by absolute pitch in songbirds (Mimus, Molothrus, and Sturnus).

Assessed the ability of starlings (Sturnus vulgaris), cowbirds (Molothrus ater), and a mockingbird (Mimus polyglottos) to maintain a relative pitch discrimination when the absolute frequencies of a serial pattern of tones were changed. In Exp I, 7 Ss learned a relative pitch discrimination between 4-tone sequences that either ascended or descended in frequency within a 1-octave range. Results show that Ss lost the discrimination completely when the frequency range was shifted an octave above or below the initial training range. Recovery of the discrimination in the novel ranges was slow, and considerable relearning was necessary. Starling Ss, however, easily generalized the relative pitch discrimination to new frequencies within the original training range. In Exp II, 4 starlings were trained on the same relative ascending–descending discrimination in 2 noncontiguous frequency ranges. Ss lost the discrimination when transferred into a novel gap of frequencies between the original training ranges. Findings demonstrate that songbirds can learn a relational discrimination between serial pitch patterns but that their ability to generalize the discrimination is constrained markedly by the frequency range in which the sound sequences are learned initially. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responsiveness to conspecific and alien song by canaries (Serinus canaria) and European starlings (Sturnus vulgaris) as a function of photoperiod.

Nine canaries and 8 European starlings were tested for responsiveness to conspecific song, alien song, or no sound at all. Responsiveness was assessed by letting the birds choose among perches associated with the different auditory stimuli. The birds were tested when they were adapted to short and to long photoperiods. The results showed that both species responded to song, especially conspecific song, more in the long-day condition than in the short-day one. For canaries, but not for starlings, perch selection also varied as a function of sex. These data show that responsiveness to song in songbirds changes as a function of day length. An important implication of this result is that song perception, as well as song production, may change with the photoperiod. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative pitch perception in Japanese monkeys (Macaca fuscata).

To investigate whether monkeys perceive relative pitch, the author trained 3 Japanese monkeys (Macaca fuscata) to detect changes from rising to falling contours of 3-tone sequences. Tone sequences were presented serially with transposition, so monkeys were urged to attend to cues other than the absolute frequency of a component tone. Results from probe tests with novel sequences showed that monkeys discriminated by the relative pitch when the frequency ranges of sequences were within the training range, showing a similar tendency as birds in previous studies (e.g., S. H. Hulse, J. Cynx, & J. Humpal, 1984). (PsycINFO Database Record (c) 2010 APA, all rights reserved)