A simple device for the preparation of exactly aligned dichotic tapes

A system is described involving three tape recorders and a control device whereby dichotic tapes can be prepared with onset alignment accurate to a few milliseconds, or to a measured asynchrony if required. No modifications of any sort are necessary for the three tape recorders. The two channels are separately recorded in the speaker’s own time, the only requirement being that the separate words be spoken with an interword interval of 350 msec or more, to provide sufficient time for starting and stopping the system. A tone burst is placed directly on tape on another channel ahead of each word, the latter being delayed by recording in tandem through two tape recorders. The first recorder is set to the delay (echo, NAB) facility, while the tone is recorded directly on the second. Subsequently, when this is done for each item on the two speech channels, the device, described below. utilizes the tone bursts to align the two input recorders. It then rerecords each pair of words on to the third (output or dichotic) machine, to the desired synchrony/asynchrony, and interitem interval. The system can be left to align the two channels automatically. A maximum repetition rate of two dichotic pairs every 1.3 sec can be achieved with Revox A77 tape recorders.     

A method for the preparation of audio tapes for dichotic listening research

A simple method for producing audio tapes with temporally synchronized messages is described. The duration and spacing of words can be precisely controlled. This method requires a minimum of elaborate equipment, yet synchronization is very accurate with highly intelligible speech.     

Metamotivational states displayed using differential digital photoplethysmograms while listening to music and noise

The theory of psychological reversal postulates that individuals switch between paratelic and telic metamotivational states. To observe the paratelic state as an actual phenomenon using a physiological index, a correlation between changes in P-wave amplitudes of differential digital photoplethysmograms (deltaDPG) of 24 undergraduate students while listening to music and changes in mood pre- to postlistening was investigated. Elevation in arousal of the sympathetic nervous system, as indicated by deltaDPG. was related to improvement in mood. It was assumed that the subjects who were aroused more while listening to music enjoyed the high arousal more and were more susceptible to a pleasant state. This was interpreted as a paratelic state. In listening to a noise condition using another 24 undergraduate students, however, the correlation was inverse of that for the music condition. It was assumed that the subjects who spent more effort in identifying stimuli showed more elevation in arousal of the sympathetic nervous system and more aggravation in mood. This was interpreted as a telic state.     

Reliability of a dichotic consonant-vowel pairs task using an ABX procedure

The present study examined the reliability of a dichotic consonant-vowels (CV) pairs task using an ABX procedure. Twenty-four right-handed subjects (12 females, 12 males) completed a dichotic CV pairs task twice in a test-retest approach. The conventional free-recall or directed-attention procedure was replaced by an ABX procedure, in which participants were required to determine whether a CV heard binaurally was present in a dichotic pair presented on the same trial. Results showed the expected right-ear advantage in dichotic listening for verbal material. However, reliability was not as high as has been reported with a directed-attention procedure. Methods for improving the reliability of the ABX discrimination task are discussed. In addition, the discussion emphasizes the usefulness of the ABX approach for testing clinical populations.     

Adapted digital music players for individuals with severe impairments

Portable music production devices, such as radios, cassette players, and MP3 players, have characteristics that make them less than ideal for teaching the cause‐and‐effect relationships that would enable children and adults with severe impairments to control them independently and appropriately. Even when adapted for control with adaptive switches, the relationship between switch closure and on–off operation results in contingency characteristics that can inhibit learning. Some solutions to these problems are described, and for those individuals who can learn with complex contingencies, some promising products are reviewed. Copyright © 2011 John Wiley & Sons, Ltd.     

Ear asymmetry in a dichotic detection task

Pairs of consonant-vowel (CV) syllables were presented dichotically to Ss who were instructed to monitor for the presence of a target CV which could occur in either ear. Ss responded by depressing a response button ; reaction time (RT) was also recorded. Right ear targets were detected 6.2% more frequently, on the average, than left ear targets and had an average RT 50 msec quicker than their left ear counterparts. These results demonstrate the existence of a right ear superiority in dichotic listening when a nonverbal motor response measure is used, supporting the contention that the ear asymmetry phenomenon is truly perceptual in nature and not merely due to the lateralization of verbal output. Two alternative explanations of the RT difference between left and right ear targets are offered. One attributes this difference to the time necessary for intercortical transfer of right hemisphere information, while the second holds that it is due to the longer times needed by the right hemisphere to process information projected to it.     

Toward a model of dichotic listening performance

Dichotic listening performance for different classes of speech sounds was examined under conditions of controlled attention. Consideration of the complex of target item and competing item demonstrated that, in general, targets were more accurately identified when the competing item shared no relevant features with it and less accurately identified when the competing item shared place, voice, or manner with the target item. Nasals as well as stops demonstrated a significant right-ear advantage (REA). False alarm rates were very similar for left and right attentional conditions, whereas intrusions from the right ear while attending to the left were far more common than intrusions from the left while attending to the right. Attention is viewed as serving to select the stimuli that will be reported, but at a late stage, and only after the right ear perceptual advantage has had its effect. A model of dichotic listening performance is proposed in which both the ease of localizing the item and the strength of evidence for the presence of the item are relevant factors.     

Frequency selectivity using tonal-temporal masking: Diotic vs. dichotic masking

A combined forward-backward masking procedure was used to investigate the threshold of a 30-msec, 500-Hz signal as a function of masker frequency. The signal thresholds were obtained in two signal conditions, diotic (So) and dichotic (S_π), and for two different temporal separations of the maskers. The maskers were 500 msec in duration and were presented at 75 dB SPL. The function relating masked signal threshold to masker frequency was used to describe frequency selectivity in the four conditions. There were no differences in frequency selectivity measured between the diotic and dichotic signal conditions and only a small difference measured between the two intermasker interval conditions. The S_π conditions yielded lower thresholds than did the So conditions. The change in intermasker interval from 10 to 50 msec lowered the threshold maximally 18 dB for the So condition and 13 dB for the S_π condition. The results indicate that in this tonal temporal masking procedure there are no differences between the diotic and dichotic critical bands.     

Evidence for tempo-specific timing in music using a web-based experimental setup

Perceptual invariance has been studied and found in several domains of cognition, including those of speech, motor behavior, and object motion. It has also been the topic of several studies in music perception. However, the existing perceptual studies present rather inconclusive evidence with regard to the perceptual invariance of expressive timing under tempo transformation in music performance. The current study used a novel experimental methodology that took advantage of new technologies, such as an online Internet setup, high-quality audio, and state-of-the-art tempo-transformation techniques. The results show that listeners could detect which was the original performance when asked to compare 2 recordings, 1 of which was tempo-transformed to make both similar in overall tempo. This result is taken as support for the tempo-specific timing hypothesis--which predicts that a tempo-transformed performance will sound less natural than an original performance--and as counterevidence for the relationally invariant timing hypothesis, which predicts that a tempo-transformed performance will sound equally natural.     

Simultaneous masking in a dichotic emotion detection task

The present study investigated the possible role of ceiling effects in producing laterality effects of small magnitude in dichotic emotion detection. Twenty two right-handed undergraduate students participated in the present experiment. They were required to detect the presence of a target emotion in the expressions tones of happiness, sadness, anger, and neutrality presented dichotically. Stimuli were adjusted to 70 dB and occurred simultaneously with a white noise mask that had an intensity of 65, 70, 80, or 85 dB. Results showed a left ear advantage (LEA) for the 65 dB mask and a right ear advantage for the 85 dB mask, but only after two testing sessions. The possible existence of a generalized right ear bias that might affect the observed LEA for non-verbal tasks is discussed. Alternative explanations and limitations of the present experiment are also presented.     

Personality and hemisphere function: Two experiments using the dichotic shadowing technique

Two experiments using nonpsychiatric samples employed the auditory dichotic shadowing procedure to examine the relationship between psychotic predisposition or symptomatology and differential hemisphere performance. In experiment 1, right-handed Ss with high scores on the EPQ P-scale failed to show the normal right-ear preference for verbal material. This findings was not replicated in experiment 2, where there was a marginally significant tendency for right-handed Ss with high scores on the Schizotypy Scale (STA) to fail to show the normal right-ear preference. Different patterns of results were obtained for males and females in experiment 2. The results provide partial support for earlier studies on the relationship between schizotypy and differential hemisphere function. It is argued that the different patterns of means obtained in these and other studies in this area are best explained by a structural-dynamic model of hemisphere functioning.     

Hemispheric emotional asymmetry in a dichotic listening task.

In a dichotic listening experiment white noise was played to one ear and either music or poetry to the other ear. Subjects rated the stimuli on each of three dimensions. The results showed that both music poetry were judged as more pleasant when heard at the left than the right ear. In addition the music, but not the poetry, was perceived as more soothing at the left ear. The findings are discussed in relation to other indications in the literature that left and right cerebral hemispheres differ in their emotional make-up.     

Response-initiated imaging of operant behavior using a digital camera

A miniature digital camera, QuickCam Pro 3000, intended for use with video e-mail, was modified so that snapshots were triggered by operant behavior emitted in a standard experimental chamber. With only minor modification, the manual shutter button on the camera was replaced with a simple switch closure via an I/O interface controlled by a PC computer. When the operant behavior activated the I/O switch, the camera took a snapshot of the subject's behavior at that moment. To illustrate the use of the camera, a simple experiment was designed to examine stereotypy and variability in topography of operant behavior under continuous reinforcement and extinction in 6 rats using food pellets as reinforcement. When a rat operated an omnidirectional pole suspended from the ceiling, it also took a picture of the topography of its own behavior at that moment. In a single session after shaping of pole movement (if necessary), blocks of continuous reinforcement, in which each response was reinforced, alternated with blocks of extinction (no reinforcement), with each block ending when 20 responses had occurred. The software supplied with the camera automatically stored each image and named image files successively within a session. The software that controlled the experiment also stored quantitative data regarding the operant behavior such as consecutive order, temporal location within the session, and response duration. This paper describes how the two data types--image information and numerical performance characteristics-can be combined for visual analysis. The experiment illustrates in images how response topography changes during shaping of pole movement, how response topography quickly becomes highly stereotyped during continuous reinforcement, and how response variability increases during extinction. The method of storing digital response-initiated snapshots should be useful for a variety of experimental situations that are intended to examine behavior change and topography.     

The processing of fundamental frequency in a dichotic matching task

The temporal characteristics of auditory memory were investigated using a reaction time paradigm. The study attempted to determine whether or not there are functionally distinct left and right hemisphere components of auditory memory with different capacities for the retention of nonlinguistic information, such as fundamental frequency, over the course of several seconds. The results indicated that fundamental frequency information in auditory memory remains substantially unchanged over the course of 2 sec. No evidence was found for the existence of separate left and right hemisphere components of auditory memory with different temporal characteristics. The implications of this finding for the organization of auditory memory in the brain are discussed.     

Diotic and dichotic frequency recognition in a single-interval temporal interference procedure

The frequency discriminability of a 70-dB SPL, 20-msec test tone followed 5 msec later by an equally intense 500-msec, 800-Hz interference tone was studied in a single-interval procedure for one diotic condition and three dichotic conditions. The test tone (T) and interference tone (I) were presented the same to both ears (ToIo, diotic condition) and in three dichotic conditions: (1) the interference tone was presented to the right ear (R) and the test tone to the left ear (L) (T_LI_R), (2) the interference tone was presented the same to both ears and the test tone to one ear (TmIo), and (3) the interference tone was presented the same to both ears and the test tone to both ears with an interaural phase reversal (TπIo). The threshold value for test tone frequency discrimination in the diotic temporal interference condition was approximately six times greater than that obtained without an interference tone. The three dichotic temporal interference conditions yielded essentially equivalent threshold values which were approximately 2.4 times that obtained when the test tone was presented without an interference tone. Therefore, although never equaling interference-free conditions, dichotic test tone presentations can improve frequency recognition relative to diotic conditions at intensities well above threshold. It is postulated that this improvement may be due to the spatial separation of test and interfering tones, rather than to possible differences in diotic vs. dichotic subjective intensities. Dichotic-diotic frequency recognition differences did not occur when a 100-msec interval separated the test and interfering tone or when the interfering tone preceded the test tone.     

Hemispheric performance in detecting prosody: a competitive dichotic listening task

Ross's 1981 model of right-hemisphere processing of affective speech components was investigated within the dichotic paradigm. A spoken sentence constant in semantic content but varying among mad, sad, and glad emotional tones was presented to 45 male and 45 female college students. Duration of stimuli was controlled by adjusting digital sound samples to a uniform length. No effect of sex emerged, but the hypothesized ear advantage was found: more correct identifications were made with the left ear than with the right. A main effect of prosody was also observed, with significantly poorer performance in identifying the sad tone; in addition, sad condition scores for the right ear were more greatly depressed than those for the left ear, resulting in a significant interaction of ear and prosody.     

Attentional set in pure- versus mixed-lists in a dichotic listening paradigm

An experiment was designed to assess the contribution of attentional set to performance on a forced choice recognition task in dichotic listening. Subjects were randomly assigned to one of three conditions: speech sounds composed of stop consonants, emotional nonspeech sounds, or a random combination of both. In the groups exposed to a single class of stimuli (pure-list), a REA (right ear advantage) emerged for the speech sounds, and a LE (left ear advantage) for the nonspeech sounds. Under mixed conditions using both classes of stimuli, no significant ear advantage was apparent, either globally or individually for the speech and nonspeech sounds. However, performance was more accurate for the left ear on nonspeech sounds and for the right ear for speech sounds, regardless of pure versus mixed placement. The results suggest that under divided attention conditions, attentional set influences the direction of the laterality effect.