Masking of noise bursts by an adjacent vowel for hearing-impaired listeners

Some masking effects of synthetic vowels on adjacent noise bursts are reported for hearing-impaired listeners. The 200-ms vowels were similar to [a] and [i]; the 50-ms noise bursts were in one of three frequency bands: .5 to 1.5, 1.5 to 4, or 4 to 6 kHz. With voiceless-stop-like temporal intervals between the stimuli, there was little backward or forward masking of the noise bursts by either vowel. Some forward masking occurred under proximate conditions of vowel and burst in time and frequency.     

Characteristics of perceptual grouping in rats

Parametric analysis was made of the characteristics by which proximity and alignment serve as cues for perceptual grouping in rats. Rats were initially conditioned to discriminate a series of horizontal lines from vertical lines. Following training, rats were presented with test stimuli that consisted of bistable arrays of disjunct dots. A grouping cue (greater proximity, greater alignment, or both) was randomly assigned to either the horizontal or vertical orientation. The effectiveness of the cues was based on behavioral responses to the cued orientation. Results indicated that proximity served as a cue for perceptual grouping. The effectiveness of the proximity cue was less for rats than found previously in humans and, unlike humans, diminished with increased stimulus scale. Rats did not respond to alignment cues when used in isolation, although alignment facilitated grouping when used in conjunction with proximity cues. Diminished effectiveness of grouping cues likely reduces object recognition abilities, particularly for complex visual stimuli.     

Effects of signaling retention interval length on delayed matching-to-sample in pigeons.

Pigeons were trained initially on a delayed matching task in which colors served as sample and comparison stimuli. During subsequent training, additional stimuli compounded with the sample signaled whether that trial involved a short (1 s) or a long (5 s) delay. In Experiment 1, miscuing reduced accuracy at the short delay markedly and tended to increase accuracy at the long delay slightly. Experiments 2 and 3 revealed a robust effect of cuing when the cues followed sample termination, thereby refuting the view that such cues evoke differential attention to the sample stimulus. Experiment 4 revealed that the cues did not influence rate of forgetting, and Experiment 5 revealed no effect of point of cue placement within the retention interval. It was concluded that cues correlated with retention interval length modulated matching accuracy independently of memory, perhaps by signaling different rates of reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative spectral change and formant transitions as cues to labial and alveolar place of articulation

The perceptual salience of relative spectral change [Lahiri et al., J. Acoust. Soc. Am. 76, 391-404 (1984)] and formant transitions as cues to labial and alveolar/dental place of articulation was assessed in a conflicting cue paradigm. The prototype stimuli were produced by two English speakers. The stimuli with conflicting cues to place of articulation were created by altering the spectra of the signals so that the change in spectral energy from signal onset to voicing onset specified one place of articulation while the formant transitions specified the other place of articulation. Listeners' identification of these stimuli was determined principally by the information from formant transitions. This outcome provides no support for the view that the relative spectral change is a significant perceptual cue to stop consonant place of articulation.     

Auditory perception of fractal contours.

A series of experiments examined auditory contour formation, investigating listeners' sensitivities to a family of random fractals known as fractional Brownian noises. Exps 1A and 1B looked at identification of contours when 3 different noises were portrayed using variations in the pitch, duration, or loudness of successive notes of a sequence. Listeners could categorize pitch and loudness encodings, but not duration mappings. Exp 2 looked at the effect of simultaneous presentation of pitch and loudness information, finding that these dimensions combined additively to increase identification of the noise distributions. Exp 3 looked at discrimination of pitch contours as a function of changing fractal dimension. Discrimination curves approximated an inverted U shape, a finding that is not understandable in terms of sensitivity to differences in fractal dimension per se, nor in terms of "tuned" perceptual sensitivity to statistical regularities of the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampectomy disrupts trace eye-blink conditioning in rabbits.

The role of the hippocampus (HPC) in trace eye-blink conditioning was evaluated using a 100-ms tone conditioned stimulus/stimuli (CS), a 300- or 500-ms trace interval, and a 150-ms air puff unconditioned stimulus/stimuli (UCS). Rabbits received complete hippocampectomy (dorsal & ventral), sham lesions or neocortical lesions. Hippocampectomy produced differential effects in relation to the trace interval used. With a 300-ms trace interval, HPC-lesioned Ss showed profound resistance to extinction after acquisition. With a 500-ms trace interval, HPC-lesioned Ss did not learn the task (only 22% conditioned responses [CRs] after 25 sessions, whereas controls showed >80% after 10 sessions), and on the few trials in which a CR occurred, most were "nonadaptive" short-latency CRs (i.e., they started during or just after the CS and always terminated prior to UCS onset). The authors conclude that the HPC encodes a temporal relationship between CS and UCS, and when the trace interval is long enough (e.g., 500 ms), that the HPC is necessary for associative learning of the conditioned eye-blink response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feature modulation search: A novel memory search model that extends the perceptual interference effect to musical stimuli.

Although most research in the perceptual interference literature has used visual stimuli, recent experiments have replicated this effect using musical stimuli. Two experiments investigated whether musical and visual demonstrations of the effect are produced by a common mechanism by examining whether the provision of incorrect cues would impair melodic object identification in the perceptual interference paradigm. Whereas incorrect cues typically do not affect visual object identification, they reduced melody identification both when the subjects generated the cues and when the experimenter provided them. A novel model (feature modulation search) is presented to account for perceptual interference in musical stimuli. The model has potential applications for the larger perceptual interference literature and for related phenomena in which target-related information impairs cognition. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Interval and contour in serial pitch perception by a passerine bird, the European starling (Sturnus vulgaris).

Examined the capacity of starlings to perceive and process pitch information in serial acoustic patterns in 7 experiments. Exps I–III studied the discrimination of sequences of tones that rose or fell in pitch when the interval size between successive pitches changed relative to a standard baseline interval. The rising/falling discrimination maintained itself—the birds showed perceptual constancy—when intervals were halved, varied randomly in size, or changed to a continuous frequency sweep. Exps IV–VI examined discrimination performance when pitch contour (i.e., up and down pitch relation from tone to tone) was changed from the baseline patterns. Ss responded preferentially to early rising/falling pitch information on a pitch sequence; they ignored later relative pitch information even when it contradicted early information. However, they could delay pitch processing if initial tones lacked up or down pitch cues. Exp VII was an exploration of the birds' consistent predilection to use absolute frequency value, as opposed to relative pitch, as a discriminative cue in pitch pattern perception. Results suggest a comparison between the cognitive ability of humans and that of animals to process serial acoustic information. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning and generalization of a two-dimensional sameness-difference concept by chimpanzees and orangutans.

Taught 4 adult chimpanzees and 4 orangutans a 2-dimensional sameness-difference concept in which the positive pair of stimuli were the same color (or form) and different forms (or colors), while the negative pair were the same form (or color) and different colors (or forms). Testing with nondifferentially reinforced equivalence trials showed that the training generalized to a set of novel stimuli. Further equivalence trials demonstrated that color was more salient than form. Equivalence trials demonstrated that color was more salient than form. Equivalence trials with 3- instead of 2-object arrays as stimuli revealed significant generalization gradients along the heterogeneity-homogeneity dimension for both color and form cues. There were no important differences in the performances of the chimpanzees and the orangutans. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classic conditioning in aged rabbits: Delay, trace, and long-delay conditioning.

Young (0.5 yr old) and aged (2+, 3+, and 4+ yr old) rabbits underwent acquisition of the classically conditioned nictitating membrane response in a delay (500-ms conditioned stimulus [CS], 400-ms interstimulus interval [ISI]), long-delay (1,000-ms CS, 900-ms ISI), or trace (500-ms CS, 400-ms stimulus-free period) paradigm. Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning. Collapsing across conditioning paradigms, there is a general tendency for aged animals to acquire more slowly than younger animals. Of greater significance, however, are the age differences in the different conditioning paradigms. In the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4+ yr old group. In the trace conditioning paradigm, significant conditioning deficits became apparent in the 2+ yr old animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistent complex subliminal activation effects: First experimental observations.

A strong recent focus on unconscious processes has increased interest in subliminal stimulation and other experimental activation technologies. Five experiments using male and female university students (N = 365) were carried out to compare 5-ms exposures of "mommy and I" stimuli with 5-ms control stimulation. Measures of self-mother similarity and other variables taken 7-14 days after exposure were more strongly correlated among experimental participants. Such complex, persistent effects may follow when powerfully activating stimuli administered under wholly unconscious conditions provokes schematic processing of social information and behavioral confirmation. These scientifically exciting and ethically problematic findings imply a need for further reduction of the role accorded to conscious volition and control in psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of continuous versus pulsed CO2 and Nd:YAG laser-induced pulmonary parenchymal lung injury in a rabbit model

Two studies investigated the effects of delayed visual feedback on manual tracking. In Experiment 1, individuals practiced with visual feedback provided either immediately (0 delay) or with a 333-ms delay. During acquisition, the 0 delay group performed with less error than the 333-ms delay group. A retention test with 0 delay feedback was performed with the least error by the 0 delay group. A transfer test using a different 0 delay tracking pattern, was performed with the least error by the 333-ms delay group. In Experiment 2, individuals practiced at six different delays. Error increased as training feedback delay increased. For retention there were no differences between the delay groups during the 0 delay retention. At a 417-ms retention, test error decreased as training feedback delay increased. Results indicate that error during acquisition does not necessarily impair learning and that feedback delays can be beneficial for learning.     

Proximal versus distal cues to smoke: The effects of environments on smokers' cue-reactivity.

Smokers are highly reactive to smoking-related cues that are directly linked, or most proximal, to actual smoking behavior (e.g., lit cigarettes). However, over the course of smoking, proximal cues may not be the only stimuli to become strongly associated with smoking. Distal cues, such as the environments in which smoking occurs (e.g., bar) might also gain associative properties and come to evoke robust reactivity from smokers. To test this, a pilot study was first conducted to develop standard pictorial stimuli of smoking and nonsmoking environments, all of which were completely devoid of proximal smoking cues. A comparison set of smoking and nonsmoking proximal cues was then created. Using the 12 total pictorial cues developed, 62 adult smokers participated in a cue-reactivity study during which they viewed and rated pictorial smoking and nonsmoking environment and proximal cues. Results demonstrate that, similar to proximal cues, environments associated with smoking can alone function as stimuli capable of evoking strong subjective reactivity from smokers. This work supports a broader conceptualization of drug-related cues in cue-based research and treatment development that includes proximal and distal cues as distinct categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

Simon effect with and without awareness of the accessory stimulus.

The authors investigated whether a Simon effect could be observed in an accessory-stimulus Simon task when participants were unaware of the task-irrelevant accessory cue. In Experiment 1A a central visual target was accompanied by a suprathreshold visual lateral cue. A regular Simon effect (i.e., faster cue-response corresponding reaction times [RTs]) was found. Experiment 1B demonstrated that this effect cannot be attributed to perceptual grouping of the target and cue. Experiments 2A, 2B, and 2C showed a reverse Simon effect (i.e., faster noncorresponding RTs) when participants were not aware of the cue. In this condition, the Simon effect would occur relative to the reorientation of attention from the cue, which would initially capture attention, toward the target. This conclusion is supported by the results of Experiments 3A and 3B, in which the reorientation of attention was induced by having the target flash after its onset. With suprathreshold cues either a reverse or regular Simon effect was observed by using a 100-ms or ≥200-ms onset flashing interval, respectively, whereas with subthreshold cues a reverse Simon effect was found irrespective of the interval length. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An objective measurement of the build-up of auditory streaming and of its modulation by attention.

Three experiments studied auditory streaming using sequences of alternating “ABA” triplets, where “A” and “B” were 50-ms tones differing in frequency by Δf semitones and separated by 75-ms gaps. Experiment 1 showed that detection of a short increase in the gap between a B tone and the preceding A tone, imposed on one ABA triplet, was better when the delay occurred early versus late in the sequence, and for Δf = 4 vs. Δf = 8. The results of this experiment were consistent with those of a subjective streaming judgment task. Experiment 2 showed that the detection of a delay 12.5 s into a 13.5-s sequence could be improved by requiring participants to perform a task on competing stimuli presented to the other ear for the first 10 s of that sequence. Hence, adding an additional task demand could improve performance via its effect on the perceptual organization of a sound sequence. The results demonstrate that attention affects streaming in an objective task and that the effects of build-up are not completely under voluntary control. In particular, even though build-up can impair performance in an objective task, participants are unable to prevent this from happening. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Acoustic cues to grammatical structure in infant-directed speech: cross-linguistic evidence

Several theorists have suggested that infants use prosodic cues such as pauses, final lengthening, and pitch changes to identify linguistic units in speech. One potential difficulty with this proposal, however, is that the acoustic shape of an utterance is affected by many factors other than its syntax, including its phonetic, lexical, and discourse structure. This has raised questions about how the infant could use timing and pitch as cues to any aspect of linguistic structure without simultaneously factoring out other effects. Acoustic analyses of connected samples of spontaneous speech addressed to 13.5-14-month-old infants by American English- and by Japanese-speaking mothers revealed that both utterance- and phrase-level acoustic regularities were large enough to be detected in spontaneous speech without correcting for other influences on the same acoustic features. (1) Utterance-final vowels were lengthened and underwent exaggerated pitch changes in both languages, and (2) local acoustic changes in duration (English) or pitch (Japanese) were reliably associated with some phrase boundaries within utterances. These findings suggest that a naive listener could estimate a rough prosodic template for each language based on robust acoustic patterns in observed sentences. We discuss ways in which the learner could combine acoustic and distributional analyses across utterances to acquire language-specific variations in prosodic bracketing cues and to obtain indirect perceptual evidence for the internal structure of utterances.     

Absolute pitch in infant auditory learning: Evidence for developmental reorganization.

To what extent do infants represent the absolute pitches of complex auditory stimuli? Two experiments with 8-month-old infants examined the use of absolute and relative pitch cues in a tone-sequence statistical learning task. The results suggest that, given unsegmented stimuli that do not conform to the rules of musical composition, infants are more likely to track patterns of absolute pitches than of relative pitches. A 3rd experiment tested adults with or without musical training on the same statistical learning tasks used in the infant experiments. Unlike the infants, adult listeners relied primarily on relative pitch cues. These results suggest a shift from an initial focus on absolute pitch to the eventual dominance of relative pitch, which, it is argued, is more useful for both music and speech processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dimensional interaction between color and pitch.

In three experiments I investigated the nature of cross–modal dimensional interaction by testing speeded classification of the synesthetically corresponding dimensions of color (white–black) and pitch (high–low). Experiment 1 showed significant Garner interference when these dimensions were varied orthogonally—redundancy gain for positively correlated dimensions and redundancy loss for negatively correlated dimensions. Attributes from synesthetically congruent stimuli were classified faster than attributes from incongruent stimuli (a congruity effect). Experiment 2 tested a perceptual explanation of this interaction (i.e., that color and pitch are configural dimensions) by using Pomerantz's (1986) diagnostic (comparison of selective and divided attention performance). The configurality hypothesis received little support. Experiment 3 examined the effect of optional processes on color and pitch classification. The results suggest that partly strategic and partly mandatory components may constitute overall performance. Three alternative explanations of the color–pitch interaction—perceptual, semantic, and response based—are evaluated in the context of the present results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulation of the acquisition of the rabbit eyeblink conditioned response by conditioned contextual stimuli.

Three experiments were conducted to ask if conditioned emotional responses (CERs) controlled by contextual cues modulate the acquisition of eyelid conditioned responses (CRs) to discrete conditioned stimuli (CSs). Experiment 1 showed that 30-s auditory stimuli that were paired with aversive shocks to one paraorbital region or the other controlled discriminated CERs, as measured by potentiation of a startle response. In Experiments 2 and 3, similarly trained 30-s stimuli served as contexts in which 1,050-ms CSs were paired with a paraorbital unconditioned stimulus (US). Reinforced contexts both impaired (Experiments 2A and 2B) and facilitated (Experiment 3B) acquisition of the eyeblink CR, depending on the locus of the USs involved. The data are consistent with the interpretation that CERs controlled by contextual cues facilitate CR acquisition, but do so in the face of blocking effects of CR tendencies also conditioned to the contextual cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)