Constraints on the selection of auditory information.

Four experiments were conducted to determine whether or not (a) selection of auditory information may be guided separately by location and frequency channels and (b) auditory attention is allocated to spatial locations and frequency regions or to auditory objects (i.e., streams). In Experiment 1, listeners were to categorize tones by location or frequency. In Experiments 2A and 2B, target identification was examined as a function of its similarity to a precue. In Experiment 3, the time required to detect a target embedded within a sequence of distractor tones was examined. In all experiments, performance depended on both location and frequency information even if 1 of these features was completely irrelevant with respect to the task. Results indicate that selection of auditory information is accomplished by an attentional template normally defined by both location and frequency parameters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The control of food-caching behavior by Western scrub-jays (Aphelocoma californica).

Western scrub-jays (Aphelocoma californica) did not show extinction when caching behavior was never rewarded and they had no choice of where to cache the food. However, when the jays had the choice of caching items in 2 different locations or during 2 successive episodes, and only 1 of each was always rewarded at recovery, they rapidly learned to cache in the rewarded location or episode. When the jays had learned during training trials that their caches were always moved to 1 of 2 locations they did not cache in, then on the test trial they cached in the location that had been previously rewarded. To test whether these jays avoided the location in which their caches had been pilfered or chose the rewarded location, the procedure was repeated to include a 3rd location that was never rewarded. The jays avoided the pilfered location but cached equally in the rewarded and nonrewarded locations. (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)     

Correction to Roberts et al. (2008).

Reports an error in "Effects of the build-up and resetting of auditory stream segregation on temporal discrimination" by Brian Roberts, Brian R. Glasberg and Brian C. J. Moore (Journal of Experimental Psychology: Human Perception and Performance, 2008[Aug], Vol 34[4], 992-1006). The year listed is incorrect. The article should have been dated 2008. (The following abstract of the original article appeared in record 2008-09670-016.) The tendency to hear a tone sequence as 2 or more streams (segregated) builds up, but a sudden change in properties can reset the percept to 1 stream (integrated). This effect has not hitherto been explored using an objective measure of streaming. Stimuli comprised a 2.0-s fixed-frequency inducer followed by a 0.6-s test sequence of alternating pure tones (3 low [L]-high [H] cycles). Listeners compared intervals for which the test sequence was either isochronous or the H tones were slightly delayed. Resetting of segregation should make identifying the anisochronous interval easier. The HL frequency separation was varied (0-12 semitones), and properties of the inducer and test sequence were set to the same or different values. Inducer properties manipulated were frequency, number of onsets (several short bursts vs. one continuous tone), tone:silence ratio (short vs. extended bursts), level, and lateralization. All differences between the inducer and the L tones reduced temporal discrimination thresholds toward those for the no-inducer case, including properties shown previously not to affect segregation greatly. Overall, it is concluded that abrupt changes in a sequence cause resetting and improve subsequent temporal discrimination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of the build-up and resetting of auditory stream segregation on temporal discrimination.

[Correction Notice: An erratum for this article was reported in Vol 34(6) of Journal of Experimental Psychology: Human Perception and Performance (see record 2008-16831-007). The year listed is incorrect. The article should have been dated 2008.] The tendency to hear a tone sequence as 2 or more streams (segregated) builds up, but a sudden change in properties can reset the percept to 1 stream (integrated). This effect has not hitherto been explored using an objective measure of streaming. Stimuli comprised a 2.0-s fixed-frequency inducer followed by a 0.6-s test sequence of alternating pure tones (3 low [L]-high [H] cycles). Listeners compared intervals for which the test sequence was either isochronous or the H tones were slightly delayed. Resetting of segregation should make identifying the anisochronous interval easier. The HL frequency separation was varied (0-12 semitones), and properties of the inducer and test sequence were set to the same or different values. Inducer properties manipulated were frequency, number of onsets (several short bursts vs. one continuous tone), tone:silence ratio (short vs. extended bursts), level, and lateralization. All differences between the inducer and the L tones reduced temporal discrimination thresholds toward those for the no-inducer case, including properties shown previously not to affect segregation greatly. Overall, it is concluded that abrupt changes in a sequence cause resetting and improve subsequent temporal discrimination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Randomized, double-blind clinical trial of amphotericin B colloidal dispersion vs. amphotericin B in the empirical treatment of fever and neutropenia

The possibility that there is an inhibitory component to auditory covert orienting was addressed. Each trial consisted of a cue followed by a target, and listeners were required to detect, localize, or identify the frequency of the target. At 150-msec stimulus onset asynchrony (SOA), performance was best when stimuli sounded from the same location or were of the same frequency. However, at 750-msec SOA, performance was best when stimuli differed in location or were of different frequencies. These results document the existence of both location-based and frequency-based auditory inhibition of return.     

Intensity discrimination for precedence effect stimuli

When two identical stimuli are presented from two loudspeakers with a brief delay between them, a single image is heard near the source of the leading sound. The delayed sound or echo appears to be suppressed whereas the preceding sound determines perceived location, hence the name, the precedence effect. This study investigated normal-hearing listeners' sensitivity to changes in the intensity of the lagging sound. Pairs of 2-ms white noise bursts, with a 2-ms delay between the onsets of lead and lag, were presented from two loudspeakers 45 degrees left and right of midline in an anechoic chamber. A 2AFC procedure was used to test discrimination of intensity changes in the lead, lag, and both sounds together. The untreated results showed discrimination to be poorest for changes in the lag stimulus. However, when the intensity differences were transformed into predictions of equivalent monaural level based on KEMAR measurements and binaural loudness summation, discrimination for the lag was equal to the other two conditions. A follow-up experiment found that listeners were highly sensitive to the presence of the lag, more sensitive than would be predicted from loudness changes. It is concluded that the precedence effect does not consist of a general suppression or attenuation of the lagging sound, but rather that suppression may be limited to directionality cues.     

Adaptation reveals multiple levels of representation in auditory stream segregation.

When presented with alternating low and high tones, listeners are more likely to perceive 2 separate streams of tones (“streaming”) than a single coherent stream when the frequency separation (Δ?) between tones is greater and the number of tone presentations is greater (“buildup”). However, the same large-Δ? sequence reduces streaming for subsequent patterns presented after a gap of up to several seconds. Buildup occurs at a level of neural representation with sharp frequency tuning. The authors used adaptation to demonstrate that the contextual effect of prior Δ? arose from a representation with broad frequency tuning, unlike buildup. Separate adaptation did not occur in a representation of Δ? independent of frequency range, suggesting that any frequency-shift detectors undergoing adaptation are also frequency specific. A separate effect of prior perception was observed, dissociating stimulus-related (i.e., Δ?) and perception-related (i.e., 1 stream vs. 2 streams) adaptation. Viewing a visual analogue to auditory streaming had no effect on subsequent perception of streaming, suggesting adaptation in auditory-specific brain circuits. These results, along with previous findings on buildup, suggest that processing in at least 3 levels of auditory neural representation underlies segregation and formation of auditory streams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparative analysis of the categorization of multidimensional stimuli: II. Strategic information search in humans (Homo sapiens) but not in pigeons (Columba livia).

Pigeons and undergraduates learned conditional discriminations involving multiple spatially separated stimulus dimensions. Under some conditions, the dimensions were made available sequentially. In 3 experiments, the dimensions were all perfectly valid predictors of the response that would be reinforced and mutually redundant; in 2 others, they varied in validity. In tests with stimuli in which 1 of the 3 dimensions took an anomalous value, most but not all individuals of both species categorized them in terms of single dimensions. When information was delivered as a function of the passage of time, some students, but no pigeons, waited for the most useful information, especially when the cues differed in objective validity. When the subjects could control information delivery, both species obtained information selectively. When cue validities varied, almost all students tended to choose the most valid cues, and when all cues were valid, some chose the cues by which they classified test stimuli. Only a few pigeons chose the most useful information in either situation. Despite their tendency to unidimensional categorization, the pigeons showed no evidence of rule-governed behavior, but students followed a simple “take-the-best” rule. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual processing of multidimensional and unidimensional auditory stimuli.

Stimulus context (the distribution of stimulus values) can strongly affect both perception and judgment. In 14 experiments, the method of magnitude estimation revealed 2 fundamentally different kinds of context effect in loudness. An assimilative effect dominated when stimuli varied unidimensionally (in intensity only). But a contrastive, or adaptationlike, effect dominated when stimuli varied multidimensionally (in frequency and intensity). In Exp 15, direct loudness comparison revealed a potent, adaptational process specific to the signal frequency. Taken together, these and other results are compatible with the view that loudness perception and judgment reflect the net outcome of 2 different contextual processes: a relatively early (though probably not peripheral) process of perceptual adaptation and a later process of response-dependent assimilation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Qualities and locations of stimuli and responses affecting discrimination learning of chinchillas (Chinchilla laniger) and pigeons (Columba livia).

Chinchillas and pigeons were used as subjects in separate experiments to study interactions among stimulus and response characteristics in discrimination learning. Both the stimuli and the responses could differ with respect to their "quality" and their "location." Bright versus dim lights and upper versus lower lights served as the stimulus qualities and stimulus locations for the chinchillas, respectively. Red versus green lights and upper versus lower lights served as the stimulus qualities and stimulus locations for the pigeons, respectively. Respond versus no-respond and respond-left versus respond-right served as the response qualities and response locations, for both species, respectively. In both experiments, response–quality performance was superior when the discriminative stimuli differed in quality than when they differed in location, whereas response–location performance was superior when the discriminative stimuli differed in location than when they differed in quality. These results were interpreted within the framework provided by a general law of learning, that is, the "quality-location hypothesis." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relative importance of location and feature cues for homing pigeon (Columba livia) goal recognition.

Homing pigeons were raised and trained in two lofts that differed with respect to their color features and location in space. During training, pigeons displayed accurate site preference for a particular loft. When tested for loft preference with the feature cues switched between the 2 lofts, the pigeons returned to the loft that occupied the correct location. In a 2nd experiment, pigeons were trained to find food hidden in I of 4 color bowls (feature cues) located next to a landmark beacon (proximal spatial cue) in a constant location in a room (distal spacial cues). On test trials, pigeons chose the bowl at the correct location in the room if either the color bowl or the beacon was moved by itself but chose the correct color bowl next to the beacon if they were moved together. Together, the data suggest that the importance of location and feature information for goal recognition may be context specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Recalibrating" the auditory system: The perception of loudness.

Listening to relatively intense tones at one frequency and weak tones at another makes the latter relatively louder. The auditory system's relative response to low-frequency (f?) and high-frequency (f?) tones depends on the separation between f? and f?. When f? and f? differ little, loudness matches change little with shifts in mean sound pressure levels (SPLs) at each frequency; but when f? and f? differ more, matches change markedly, showing how the auditory system "recalibrates" its responses to f? and f?. The magnitude of recalibration and its frequency bandwidth also depend to a modest degree on the range of SPLs, their mean level, and the experimental paradigm. The representation of loudness reflects the processing and recalibration of multidimensional peripheral inputs within a higher level, context-sensitive (adaptation-like) mechanism. Other perceptual modalities show evidence of analogous mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of context on auditory stream segregation.

The authors examined the effect of preceding context on auditory stream segregation. Low tones (A), high tones (B), and silences (-) were presented in an ABA- pattern. Participants indicated whether they perceived 1 or 2 streams of tones. The A tone frequency was fixed, and the B tone was the same as the A tone or had 1 of 3 higher frequencies. Perception of 2 streams in the current trial increased with greater frequency separation between the A and B tones (Δf). Larger Δf in previous trials modified this pattern, causing less streaming in the current trial. This occurred even when listeners were asked to bias their perception toward hearing 1 stream or 2 streams. The effect of previous Δf was not due to response bias because simply perceiving 2 streams in the previous trial did not cause less streaming in the current trial. Finally, the effect of previous Δf was diminished, though still present, when the silent duration between trials was increased to 5.76 s. The time course of this context effect on streaming implicates the involvement of auditory sensory memory or neural adaptation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual–motor sequence learning of general regularities and specific sequences.

Participants viewed digit strings and typed them on a computer keyboard. When they used the same key configuration across training and test, they typed test strings that adhered to the same sequence rule as training strings faster than test strings that adhered to the opposite rule (general-regularity [GR] learning), and they typed test strings that were processed repeatedly during training faster than test strings that were not (specific-sequence [SS] learning). However, when they used different key configurations at training and at test, GR learning, but not SS learning, was observed. Conversely, when they did not type but spoke the strings aloud during training, SS learning, but not GR learning, was observed. Results suggest that in addition to declarative memory for specific sequences, relatively independent subsystems underlie procedural learning of perceptual-motor sequence components (producing GR effects) and sequence wholes (producing SS effects). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of frequency, amplitude, and azimuth of a vibratory dipole source by the octavolateralis system of goldfish (Carassius auratus).

Goldfish (Carassius auratus) were conditioned to suppress respiration to a 40-Hz vibratory source and subsequently tested for stimulus generalization to frequency, stimulus amplitude, and position (azimuth). Animals completely failed to generalize to frequencies separated by octave intervals both lesser and greater than the CS. However, they did appear to generalize weakly to an aerial loudspeaker stimulus of the same frequency (40 Hz) after conditioning with an underwater vibratory source. Animals had a gradually decreasing amount of generalization to amplitude changes, suggesting a perceptual dimension of loudness. Animals generalized largely or completely to the same underwater source presented at a range of source azimuths. When these azimuths were presented at a transect of 3 cm, some animals did show decrements in generalization, while others did not. This suggests that although azimuth may be perceived more saliently at distances closer to a dipole source, perception of position is not immediately salient in conditioned vibratory source detection. Differential responding to test stimuli located toward the head or tail suggests the presence of perceptual differences between sources that are rostral or caudal with respect to the position of the animal or perhaps the head. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Dynamic frequency change influences loudness perception: A central, analytic process.

Three experiments showed that dynamic frequency change influenced loudness. Listeners heard tones that had concurrent frequency and intensity change and tracked loudness while ignoring pitch. Dynamic frequency change significantly influenced loudness. A control experiment showed that the effect depended on dynamic change and was opposite that predicted by static equal loudness contours. In a 3rd experiment, listeners heard white noise intensity change in one ear and harmonic frequency change in the other and tracked the loudness of the noise while ignoring the harmonic tone. Findings suggest that the dynamic interaction of pitch and loudness occurs centrally in the auditory system; is an analytic process; has evolved to take advantage of naturally occurring covariation of frequency and intensity; and reflects a shortcoming of traditional static models of loudness perception in a dynamic natural setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of responsiveness to suprathreshold acoustic stimulation in chickens.

Observed developmental changes in a UCR to acoustic stimulation in young Hubbard?×?Hubbard chickens. Specifically, durations of distress call (peep) suppression were measured after the onsets of tones that differed in intensity and frequency in 384 newly hatched and 4-day-old chicks. Resuppression was also measured after a 6% change in the frequency of these tones, once Ss had habituated to the original tone. Data show that the suppression varied systematically as a function of age, intensity, and frequency: (a) the duration of suppression increased with increasing stimulus intensity; (b) responsiveness to high frequencies grew more rapidly over the 1st 4 days than responsiveness to low frequencies, an effect indicating a developmental gradient across frequencies with age; (c) resuppression to the 6% change in frequency increased in duration with age; and (d) young Ss suppressed vocalizations longer to loud tones in the range of their species' maternal assembly call than to other frequency–intensity combinations. These developmental trends indicate rapid changes in perceived loudness and perceptual sharpening over the first few days of postnatal life. (51 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Novel redistribution of the Ca(2+)-dependent cell adhesion molecule DdCAD-1 during development of Dictyostelium discoideum

Dictyostelium discoideum cells express DdCAD-1, a Ca(2+)-dependent cell-cell adhesion molecule, soon after the initiation of development. DdCAD-1 is a soluble protein which shares a significant degree of sequence similarity with E-cadherin. Laser scanning confocal microscopy of the subcellular localization of DdCAD-1 has revealed a nonrandom pattern of DdCAD-1 distribution. DdCAD-1 is present mostly as diffusely stained material in the cytoplasm during the initial stage of development. However, a drastic redistribution takes place before the onset of cell aggregation, when DdCAD-1 become localized predominantly at the cell periphery and an enrichment of DdCAD-1 occurs on membrane ruffles. A high concentration of DdCAD-1 also becomes associated with lamellipodia and filopodia, which often appear to participate in cell contact formation. Although DdCAD-1 is present in high concentrations in contact regions during early development, it disappears rapidly from these areas during cell aggregation. This redistribution is accompanied by an accumulation of the Ca(2+)-independent cell adhesion molecule gp80 in contact regions. During chemotactic migration, DdCAD-1 is present primarily on cells at the tip and on the outer margin of cell streams. In contrast, gp80 is concentrated in contact regions among cells within well-developed streams. This dynamic redistribution suggests a unique role for DdCAD-1 in the recruitment of cells into streams and in the formation of initial contacts, but it may not be required to maintain stable contacts in the presence of gp80.     

Infants' visual following: Effects of size and sound.

In Study 1, 22 infants were observed at 1 and 2 mo of age as they visually followed 4 possible combinations of a big or small doll's head accompanied by loud or soft speech. The targets moved on a horizontal track at the Ss' eye level. Ss followed the larger and louder targets, but there was no interaction between size and loudness. Study 2, with 47 Ss, indicated that the effect of size on following was apparently general at 1 mo; at 2 mo, it was specific to heads and did not extend to other 3-dimensional objects such as geometric or animal shapes. Studies 3 and 4, with 40 9-wk-old Ss, explored the nature of the effect of sound. Results indicate that 2-mo-olds followed a variety of objects more when they were accompanied by a variety of sounds than when they were silent; their following, however, was the same whether the sound source moved conjointly with the target or was in a clearly displaced stationary location. At this age, therefore, sound apparently exerts its influence through alterations in arousal rather than through facilitation of localization. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)