An auditory localization model based on high-frequency spectral cues

We present in this paper a connectionist model that extracts interaural intensity differences (IID) from head-related transfer functions (HRTF) in the form of spectral cues to localize broadband high-frequency auditory stimuli, in both azimuth and elevation. A novel discriminative matching measure (DMM) is defined and optimized to characterize matching this IID spectrum. The optimal DMM approach and a novel back-propagation-based fuzzy model of localization are shown to be capable of localizing sources in azimuth, using only spectral IID cues. The fuzzy neural network model is extended to include localization in elevation. The use of training data with additive noise provides robustness to input errors. Outputs are modeled as two-dimensional Gaussians that act as membership functions for the fuzzy sets of sound locations. Error back-propagation is used to train the network to correlate input patterns and the desired output patterns. The fuzzy outputs are used to estimate the location of the source by detecting Gaussians using the max-energy paradigm. The proposed model shows that HRTF-based spectral IID patterns can provide sufficient information for extracting localization cues using a connectionist paradigm. Successful recognition in the presence of additive noise in the inputs indicates that the computational framework of this model is robust to errors made in estimating the IID patterns. The localization errors for such noisy patterns at various elevations and azimuths are compared and found to be within limits of localization blurs observed in humans.     

Bias in auditory priming.

Priming for previously studied words in an implicit auditory memory task has been interpreted as evidence for a presemantic perceptual representation system that encodes acoustic representations of words (B. A. Church and D. L. Schacter, see record 1994-36069-001). In this article, 3 experiments provided evidence that such priming may result instead from a bias to respond with studied words. In forced-choice identification with similar alternative choices, there was no overall improvement in performance due to prior study. Benefits for studied test words were offset by costs for similar but nonstudied test words. Prior study had no effect when forced-choice alternatives were dissimilar. The data are discussed in relation to current models of auditory information processing and a new model (R. Ratcliff and G. McKoon, in press) for priming in visual word identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear conditioning to discontinuous auditory cues requires perirhinal cortical function.

Pretraining lesions of rat perirhinal (PR) cortex impair fear conditioning to ultrasonic vocalizations (USVs) but have no effect on conditioning to continuous tones. This study attempted to deconstruct USVs into simpler stimulus features that cause fear conditioning to be PR-dependent. Rats were conditioned to one of three cues: a multicall 19-kHz USV, a 19-kHz discontinuous tone, and a 19-kHz continuous tone. The discontinuous tone duplicated the on/off pattern of the individual calls in the USV, but it lacked the characteristic frequency modulations. Well-localized neurotoxic PR lesions impaired conditioning to the USV, the discontinuous tone, and the training context. However, PR lesions had no effect on conditioning to the continuous tone. The authors suggest that the lesion effects on fear conditioning to both cues and contexts reflect the essential role of PR in binding stimulus elements together into unitary representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maturation of spatial delayed responses to auditory cues in kittens.

Tested 40 mongrel cage-reared kittens in 4 age groups (45, 60, 120, or 180 days) for locomotor delayed responses to auditory cues in a 2-choice situation. Each S was trained for 15 days (300 trials); delays of 5 different durations (0-27 sec) were randomly given in each session. Performance did not improve as a function of age. All groups showed some immediate capacity for the task, all improved with training, and in all ages more errors were made after longer than after shorter delays. The ability to remember the locus of a brief sound over short periods of time appears to be mature before weaning in kittens. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location and frequency cues in auditory selective attention.

The roles of frequency and location cues in auditory selective attention were investigated in a series of experiments in which target tones were distinguished from distractors by frequency, location, or the conjunction of frequency and location features. When frequency separations in high-rate tone sequences were greater than 1 octave, participants were fastest at identifying targets defined by frequency and were sometimes faster at identifying conjunction than location targets. Frequency salience diminished as filtering demands were reduced: At long interstimulus intervals (> 2.0 sec), performance was superior in location conditions. The results suggest that frequency may play a role in auditory selective attention tasks analogous to the role of spatial position in visual attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An analysis of cues to auditory depth perception in free space.

Physical acoustics reveals a number of stimulus correlates of sound source distance. Quantitative estimates of these stimulus correlates are compared with appropriate psychophysical thesholds. Such comparisons show that most of these stimulus correlates can, with various restrictions, provide distance information detectable by the ear(s). The stimulus correlates dealt with at greatest length are: intensity, frequency spectrum at near and far distances, binaural intensity ratio, and interaural phase (or time) differences. Problems relating to the use of some of these stimulus correlates as cues are discussed. Other possible distance cues are briefly mentioned. The possible use of much of the available physical information in making distance judgments has not yet been adequately evaluated in psychophysical studies. (48 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Type I and Type II Bias.

Errors in research do occur. Their prevalence should be viewed with alarm rather than passive acceptance as an essential concomitant of humans conducting research. The author looks at the discussion of errors in an article by Leroy Wolins (Amer. Psychologist, 1962, 17, 657-658) and an article by Emanuel Berger (Amer. Psychologist, 1962, 17, 657). The first article suggests that we may be quite unaware of the large proportion of the iceberg (erroneous research results) which is never perceived or reanalyzed. The second article pleads for experimental evaluation of research results. It would seem as though these two articles are both positively and negatively related. On the one hand, subjective evaluation and interpretation of research results may possibly expose inadvertent errors in computations (or in design, sampling, etc.). Thus, results which do not readily blend with an already established nomological network might call for statistical recomputations. On the other hand, subjective evaluation can become quite blinding when one identifies with or strongly favors certain results. In such cases, errors in computation would never be suspected, much less discovered. The author discusses experimental errors further, taking a look at Type I and Type II bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of auditory cues in a visual search task.

Can an operator in a man machine system monitoring an instrument display do it better if he has both auditory and visual cues? 50 college students were assigned randomly to one of 5 conditions tested. A simulated man machine visual display was used for visual search tasks; a headset was used for sound. "In general, it appears that auditory cueing can be used effectively in conjunction with a visual search task." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Precision of auditory localization in human infants.

The precision of auditory localization in 26- to 30-week old infants was measured with a test based on the adult minimum audible angle. In this test, the horizontal angle between loudspeakers was varied systematically to determine thresholds for discriminating rightward versus leftward sound displacements. Infants were presented with sounds that shifted from straight ahead to the left or right, and observers judged from the infants' eye and head movements to which side the sound had shifted. From trial to trial, the size of the shift was decreased after correct responding and increased after incorrect responding. Infants discriminated sound displacements of about 19°, considerably less accurate than adult values of 1–2°. These findings are discussed in terms of their methodological implications and the development of sensitivity to information for sound localization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detecting anxiety and defensiveness from visual and auditory cues

Defensive individuals have been shown to differ from nondefensive individuals on a number of physiological and behavioral measures. We report two studies on observers' inferences of defensiveness, and the contribution of communication channels in the inference of defensiveness. Observers judged high and low state anxious segments of high and low trait anxious defensive and nondefensive individuals. Accurate assessments were made of (a) defensiveness, (b) state anxiety, and (c) trait anxiety: Individuals with higher levels of each variable were perceived as more anxious compared with the lower level. Effects for defensiveness and state anxiety were greater in audio-only segments, while effects for trait anxiety were greater in video-only segments. Inferences of defensiveness were greater at higher levels of state anxiety and trait anxiety. Low trait anxious defensive individuals were perceived as more anxious than the true low trait anxious. Results for defensiveness and trait anxiety were replicated in Study 2, and observers' perceptions of state anxiety matched individuals' self-reports: Defensive individuals with maximal differences between high and low state anxiety were seen as more anxious in high state anxiety, while defensive individuals with minimal differences between high and low state anxiety were regarded as less anxious in high state anxiety.     

Effects of ear plugging on single-unit azimuth sensitivity in cat primary auditory cortex. I. Evidence for monaural directional cues

1. Single-unit recordings were carried out in primary auditory cortex (AI) of barbiturate-anesthetized cats. Neurons, sensitive to sound direction in the horizontal plane (azimuth), were identified by their responses to noise bursts, presented in the free field, that varied in azimuth and sound pressure level (SPL). SPLs typically varied between 0 and 80 dB and were presented at each azimuth that was tested. Each azimuth-sensitive neuron responded well to some SPLs at certain azimuths and did not respond well to any SPL at other azimuths. This report describes AI neurons that were sensitive to the azimuth of monaurally presented noise bursts. 2. Unilateral ear plugging was used to test each azimuth-sensitive neuron's response to monaural stimulation. Ear plugs, produced by injecting a plastic ear mold compound into the concha and ear canal, attenuated sound reaching the tympanic membrane by 25-70 dB. Binaural interactions were inferred by comparing responses obtained under binaural (no plug) and monaural (ear plug) conditions. 3. Of the total sample of 131 azimuth-sensitive cells whose responses to ear plugging were studied, 27 were sensitive to the azimuth of monaurally presented noise bursts. We refer to these as monaural directional (MD) cells, and this report describes their properties. The remainder of the sample consisted of cells that either required binaural stimulation for azimuth sensitivity (63/131), because they were insensitive to azimuth under unilateral ear plug conditions or responded too unreliably to permit detailed conclusions regarding the effect of ear plugging (41/131). 4. Most (25/27) MD cells received either monaural input (MD-E0) or binaural excitatory/inhibitory input (MD-EI), as inferred from ear plugging. Two MD cells showed other characteristics. The contralateral ear was excitatory for 25/27 MD cells. 5. MD-E0 cells (22%, 6/27) were monaural. They were unaffected by unilateral ear plugging, showing that they received excitatory input from one ear, and that stimulation of the other ear was without apparent effect. On the other hand, some monaural cells in AI were insensitive to the azimuth of noise bursts, showing that sensitivity to monaural directional cues is not a property of all monaural cells in AI. 6. MD-EI cells (70%, 19/27) exhibited an increase in responsiveness on the side of the plugged ear, showing that they received excitatory drive from one ear and inhibitory drive from the other. MD-EI cells remained azimuth sensitive with the inhibitory ear plugged, showing that they were sensitive to monaural directional cues at the excitatory ear.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of same- and different-modality spatial cues on auditory and visual target identification.

A target identification paradigm was used to study cross-modal spatial cuing effects on auditory and visual target identification. Each trial consisted of an auditory or visual spatial cue followed by an auditory or visual target. The cue and target could be either of the same modality (within-modality conditions) or of different modalities (between-modalities conditions). In 3 experiments, a larger cue validity effect was apparent on within-modality trials than on between-modalities trials. In addition, the likelihood of identifying a significant cross-modal cuing effect was observed to depend on the predictability of the cue-target relation. These effects are interpreted as evidence (a) of separate auditory and visual spatial attention mechanisms and (b) that target identification may be influenced by spatial cues of another modality but that this effect is primarily dependent on the engagement of endogenous attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word recognition cues used in matching verbal stimuli within and between auditory and visual modalities.

Administered a matching-to-sample task to 60 first graders under 4 conditions, 2 intra- and 2 intermodal. The 5 matching cues (letters and segments) were used differentially within the 4 conditions with the initial segment selected most frequently in all conditions. The 5 cues were also used differentially across the 4 task conditions. Cue choice was related to reading achievement in the visual-to-visual matching condition, with the good readers using the final word segment cue significantly more often than the initial and final consonant cue. The reading achievement of those selecting the reversal, initial word segment, or final word segment did not differ. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences and cues to deception.

In an extension of previous studies on deception and deception detection, the present study investigated the relations among individual differences, behavioral cues displayed when deceiving and telling the truth, and the perceptions of naive observers. 63 undergraduates were measured on the Self-Monitoring Scale, the Affective Communication Test, the Personality Research Form, the Eysenck Personality Inventory, their acting ability, and their overall appearance. They were then videotaped while deceiving and while telling the truth, and their verbal and nonverbal cues were rated and coded. Their success at creating an honest appearance was assessed by showing edited videotapes of their faces or their bodies to naive judges (176 undergraduates), with and without sound. Behavioral cues validly discriminated truthfulness from deception, but these valid cues were not necessarily used or were incorrectly used by the judges. Comparison of the facial and body conditions suggested explanations for the relative inaccuracy of face-viewing judges. Individual differences were related to the overall display of behavioral cues, to variance in the display of cues from deceptive to truthful conditions, to overall perceptions of truthfulness, and to successful deception. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ontogenesis of an auditory localization response from birth to four months of age.

Research on the early development of auditory localization responses is reviewed, and the existence of a U-shaped developmental function is described. It has been reported that many newborns turn toward off-centered sound sources reliably at birth and will perform well for approximately the 1st mo of life, poorly during the 2nd and 3rd mo, and well again during the 4th mo. This trend was confirmed in 3 of 4 infants who were tested extensively throughout their early months. The 4th S failed to show reliable orientation toward sounds until the 4th mo of life. During the period of temporary performance decrement, attempts to reinstate reliable responding by either introducing meaningful acoustic stimuli or eliminating possible auditory-visual conflicts were not successful. (French abstract) (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Manual performance of a repeated pattern by older and younger adults with supplementary auditory cues.

Ss performed the same M-shaped manual movement pattern on repeated trials using a visual display of instantaneous error. With practice, Ss' effective time delays were diminished by increased anticipation as evidenced by an increased correlation of their movement patterns with the input velocity. However, younger adults had lower error scores, performed larger movements, and had shorter effective time delays than did older adults. Supplementary auditory displays additionally contributed to greater anticipation. However, men exhibited this effect most with an auditory display of input velocity and women with an auditory display of input position. This benefit of the auditory displays did not carry over after these displays were withdrawn. When the visual display was additionally withdrawn, benefits of the auditory training were manifest among the older adults as relatively greater temporal modulation of movement. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Development of research on the physiological mechanisms of auditory localization.

Early work on the perception of location of a sound source was considered to be a judgment arrived at by comparing differences in the stimulation at the 2 ears. This view gave way to the dichotic time hypothesis which led to many speculations concerning the neurological mechanisms involved in localization. More recently ablation and electrophysiological techniques have been employed but as yet there is not a completely satisfactory neurological model. From Psyc Abstracts 36:01:3DI76R. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral cues to counselor expertness.

Two male and 2 female counselors at each of 3 levels of training and experience conducted an initial interview with a female confederate client who presented the same role to all counselors. Videotapes of these interviews were viewed by 120 undergraduates who rated the counselors' expertness, indicated counselor behaviors that contributed to their judgments, and rated their willingness to refer close friends to the observed counselors for various concerns. Only individual counselor performance contributed significantly to rated expertness. Data do not support those of L. D. Schmidt and S. R. Strong (see record 1970-09304-001), which show an inverse relationship between training/experience and rated expertness. Willingness to refer was differentially related to rated expertness, depending on the client concern. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The hippocampus and conditioning to contextual cues.

Two experiments are reported in which behavioral control by contextual cues was assessed in groups of rats with dorsal hippocampal (HC), neocortical (NC), or operated control (OC) lesions. Following Odling-Smee's (1975) procedure, a Pavlovian conditioning paradigm was followed in which conditioned stimuli (CS; tone, light) predicted an unconditioned stimulus (US; footshock) always, never, or half the time. Conditioning trials took place in a small black box. Subsequently, conditioning to background contextual cues was assessed by measuring the amount of time rats spent in the black box in preference to an adjacent white one with neither CS nor US presented. In OC groups and, to a lesser extent, NC groups, conditioning to background cues was inversely related to the probability that CS predicted US. In contrast to graded contextual conditioning in control groups, the HC groups consistently showed abnormally strong conditioning to context that was at or near asymptotic level. The results, which were related to current theories of the relation between contextual stimuli and CS, suggest that the hippocampus may play an important role in stimulus selection during learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deficits in auditory temporal and spectral resolution in language-impaired children

Between 3 and 6 per cent of children who are otherwise unimpaired have extreme difficulties producing and understanding spoken language. This disorder is typically labelled specific language impairment. Children diagnosed with specific language impairment often have accompanying reading difficulties (dyslexia), but not all children with reading difficulties have specific language impairment. Some researchers claim that language impairment arises from failures specific to language or cognitive processing. Others hold that language impairment results from a more elemental problem that makes affected children unable to hear the acoustic distinctions among successive brief sounds in speech. Here we report the results of psychophysical tests employing simple tones and noises showing that children with specific language impairment have severe auditory perceptual deficits for brief but not long tones in particular sound contexts. Our data support the view that language difficulties result from problems in auditory perception, and provide further information about the nature of these perceptual problems that should contribute to improving the diagnosis and treatment of language impairment and related disorders.