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.     

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.     

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.     

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.     

Temporal characteristics of primary-secondary message interference in a dichotic listening task

Previous experiments have shown that during performance of a shadowing task the unattended message is processed at a semantic level. Four experiments are reported that deal with the question of how processing of the unattended message influences the difficulty of shadowing the attended message. Experiment I demonstrated that pupil dilation measures the difficulty associated with a shadowing task. In Experiment II it was shown that during shadowing of 20-item lists pupil dilation decreases as shadowing continues when either words or white noise are in the unattended channel. These results support the idea that it takes time for the attentional mechanism to focus on the attended message. In Experiments III and IV it was found that this decrease in difficulty of shadowing is much less when the attended and unattended messages come from the same stimulus category (letter-letter, digit-digit). The results indicate that, when the unattended message is from the same stimulus category as the attended message, it can interfere with the ability of the attentional system to focus on the attended message.     

Biasing thematic contexts for ambiguous sentences in a dichotic listening experiment

In an experiment derived from Lackner and Garrett (1972) 80 subjects were given a dichotic listening task where they were presented with ambiguous sentences to an attended ear and disambiguating sentences to the other, unattended, ear. Each of the sentences was preceded by a thematic context that was biased for one meaning of the ambiguous sentence. In one-half of the instances the contexts biased a meaning consistent with that of the disambiguating sentence, and in the remaining one-half they biased the meaning of the ambiguous sentence in a way that was inconsistent with the meaning of the ambiguous sentence. The meanings of the ambiguous sentences the subjects perceived tended to be those that were consistent with the biasing context, even when that meaning was inconsistent with the meaning of the disambiguating sentence. Therefore, when ambiguous sentences are preceded by a thematic context, a single-reading explanation of the processing is more appropriate than a multiple-reading explanation.     

Measurement of body image satisfaction using computer manipulation of a digital image

The authors investigated a method for assessing body image satisfaction based on computer manipulation of a digitized image of self using a sample of 56 female students aged 17 to 22 years. The total percentage change when re-sizing the actual image to the ideal by the computer adjustment method was significantly correlated with the figural/silhouette discrepancy method. Both of these measures were correlated significantly with body part satisfaction and body mass index but not with social physique anxiety. Although for this sample the 2 methods yielded similar results, the computer adjustment method addresses several limitations of the figural/silhouette method, such as scale coarseness and the accuracy of proportional change between figural/silhouettes. Furthermore, by using the individual's actual image, potential confounds associated with stylized figure drawings that are typically based on Caucasian physical features are removed. Finally, this method also takes into account the importance of various body parts for determining body image satisfaction.     

Effects of hemispheric asymmetry on electrodermal conditioning in a dichotic listening paradigm

It was predicted that when an auditive verbal conditional stimulus (CS+), previously associated with an aversive unconditional stimulus (UCS), is presented to theright ear (initial left hemisphere input), in a dichotic listening task, with the CS-simultaneously presented in the left ear, the result would be greater resistance to extinction than when the same CS+ is presented to the left ear (initial right hemisphere input). In the same vein, it was predicted that, when a tonal CS+ is presented to theleft ear, greater resistance to extinction would occur as compared with when it is presented to the right ear. During a dichotic test phase, each group was split into two subgroups, and the CS+ and CS—repeatedly were presented simultaneously to each ear. Half of the subjects in each subgroup had the CS+ presented to the left ear. The other half had the CS+ presented to the right ear. Skin conductance responses were recorded from both hands. Results showed significantly larger responding in all groups to the CS+/UCS compound during the acquisition phase. However, during the dichotic extinction phase, the verbal CS+ right-ear subgroup showed significantly larger resistance to extinction as compared with the verbal CS+ left-ear subgroup. No differences were found between the two tonal subgroups.     

Dependent processing in dichotic listening as a function of word meaning attributes

Single dichotic word pairs were presented for immediate identification. Recognition probability was greater and response latencies shorter for high- than for low-frequency words. Both recognition measures were also affected by the frequency of the word accompanying the target word, performance being facilitated by a high-frequency partner and sometimes impaired by a low-frequency partner. Associative meaningfulness had similar, though less reliable, effects whereas the effects of word concreteness-abstractness were inconsistent. Recognition accuracy was generally superior for right-ear inputs, but recognition latency did not show consistent ear effects. Similar results were obtained under both unrestricted (Experiment 1) and controlled (Experiment 2) ear order of report instructions. The findings are consistent with a limited capacity interpretation of secondary processing in word perception.