Decision interaction between auditory channels

Observers detected signals presented in a two-channel, simultaneous detection task at 630 and 1,400 Hz. The familiar pattern of interference between the frequency channels was observed: detectability in one channel was depressed on trials when a signal or a yes response occurred in the other channel. On each trial, measures were made of the energy within specified frequency bands around each signal frequency. The relationships between these measures and performance in each channel were studied. There was no consistent relationship between the magnitude of the measure in one channel and performance in the other. Interactions between the channels probably originate in the response process of the interfering channel     

Processing two dimensions of nonspeech stimuli: the auditory-phonetic distinction reconsidered.

Nonspeech stimuli were varied along two dimensions--intensity and rise time. In a series of speeded classification tasks, subjected were asked to identify the stimuli in terms of one of these dimensions. Identification time for the dimension of rise time increased when there was irrelevant variation in intensity; however, identification of intensity was unaffected by irrelevant variation in rise time. When the two dimensions varied redundantly, identification time decreased. This pattern of results is virtually identical to that obtained previously for stimuli that vary along a linguistic and a nonlinguistic dimension. The present data, taken together with those from other studies using the same stimuli, suggest that the mechanisms underlying the auditory-phonetic distinction should be reconsidered. The results are also discussed in terms of general models of multidimensional information processing.     

Divided attention between simultaneous auditory and visual signals

Past studies of simultaneous attention to pairs of visual stimuli have used the “dual-task” paradigm to show that identification of the direction of a change in luminance, whether incremental or decremental, is “capacity-limited,” while simple detection of these changes is governed by “capacity-free” processes. On the basis of that finding, it has been suggested that the contrast between identification and detection reflects different processes in the sensory periphery, namely the responses of magno- and parvocellular receptors. The present study questions that assertion and investigates the contribution of central processing in resource limitation by applying the dual task to a situation in which one stimulus is auditory and one is visual. The results are much the same as before, with identification demonstrating the tradeoff in performance generally attributed to a limited capacity but detection showing no loss compared with single-task controls. This implies that limitations on resources operate at a central level of processing rather than in the auditory and visual peripheries.     

The control of responding by auditory stimuli: interactions between different dimensions of the stimuli.

Sounds have position in addition to other dimensions, such as intensity and frequency. Position rapidly gains control of spatially contiguous responses and this may interfere with control of responding by other acoustic dimensions. These experiments investigated interference of a tone-noise discrimination by the discrimination of acoustic position. Squirrel monkeys were studied when responding was differentially reinforced in the presence of both spectral content (tone-noise) and positional differences between the stimuli, and when responding was differentially reinforced only in the presence of spectral differences. Under the first condition, responding rapidly came under the control of the position of the noise in the two monkeys tested. The position of the tone controlled responding in one monkey; in the second monkey, responding came under the control of the spectral content of the tone. Under the second condition, responding was initially under the control of the noise in all three monkeys tested. This persisted for the duration of the condition for two of the monkeys; in one monkey, responding came under the control of the spectral content of the noise. Under the second condition, responding was also initially under the control of the position of the tone for all monkeys, but control by spectral content of the tone relatively rapidly developed in two of three monkeys.     

Spatial coding of auditory signals

Sequences of nine binary auditory signals (dots and dashes) were presented to 20 subjects in Experiment I. The subjects were instructed to internally organize the signals into two-dimensional arrays. Visual patterns (letters) could be recognized in these imaginary arrays in both upright and rotated orientations. In Experiment II, a group of nine subjects, which was instructed to use spatial imagery of this kind, reproduced significantly longer sequences of signals than nine control subjects. By means of internal spatial organization, experimental subjects were able to reproduce sequences up to 45 signals in length, whereas control subjects recalled near the chance level for portions of sequences longer than nine signals. Three levels of information processing were postulated to account for the results, with spatial organization occupying a mediating level between acoustic and verbal levels.     

Developmental trends in the interaction between auditory and linguistic processing

The developmental course of multidimensional speech processing was examined in 80 children between 3 and 6 years of age and in 60 adults between 20 and 86 years of age. Processing interactions were assessed with a speeded classification task (Garner, 1974a), which required the subjects to attend selectively to the voice dimension while ignoring the linguistic dimension, and vice versa. The children and adults exhibited both similarities and differences in the patterns of processing dependencies. For all ages, performance for each dimension was slower in the presence of variation in the irrelevant dimension; irrelevant variation in the voice dimension disrupted performance more than irrelevant variation in the linguistic dimension. Trends in the degree of interference, on the other hand, showed significant differences between dimensions as a function of age. Whereas the degree of interference for the voice-dimension-relevant did not show significant age-related change, the degree of interference for the word-dimension-relevant declined significantly with age in a linear as well as a quadratic manner. A major age-related change in the relation between dimensions was that word processing, relative to voice-gender processing, required significantly more time in the children than in the adults. Overall, the developmental course characterizing multidimensional speech processing evidenced more-pronounced change when the linguistic dimension, rather than the voice dimension, was relevant.     

The interaction between duration, velocity and repetitive auditory stimulation

Repetitive auditory stimulation (with click trains) and visual velocity signals both have intriguing effects on the subjective passage of time. Previous studies have established that prior presentation of auditory clicks increases the subjective duration of subsequent sensory input, and that faster moving stimuli are also judged to have been presented for longer (the time dilation effect). However, the effect of clicks on velocity estimation is unknown, and the nature of the time dilation effect remains ambiguous. Here were present a series of five experiments to explore these phenomena in more detail. Participants viewed a rightward moving grating which traveled at velocities ranging from 5 to 15°/s and which lasted for durations of 500 to 1500 ms. Gratings were preceded by clicks, silence or white noise. It was found that both clicks and higher velocities increased subjective duration. It was also found that the time dilation effect was a constant proportion of stimulus duration. This implies that faster velocity increases the rate of the pacemaker component of the internal clock. Conversely, clicks increased subjective velocity, but the magnitude of this effect was not proportional to actual velocity. Through considerations of these results, we conclude that clicks independently affect velocity and duration representations.     

The Signal-Cognition interface: Interactions between degraded auditory signals and cognitive processes

A hearing loss leads to problems with speech perception; this is exacerbated when competing noise is present. The speech signal is recognized by the cognitive system of the listener; noise and distortion tax the cognitive system when interpreting it. The auditory system must interact with the cognitive system for optimal signal decoding. This article discusses this interaction between the signal and cognitive system based on two models: an auditory model describing signal transmission and degeneration due to a hearing loss and a cognitive model for Ease of Language Understanding. The signal distortion depends on the specifics of the hearing impairment and thus differently distorted signals can affect the cognitive system in different ways. Consequently, the severity of a hearing loss may not only depend on the lesion itself but also on the cognitive recourses required to interpret the signal.     

Reaction time to the second of two shortly spaced auditory signals both varying in intensity

Six subjects participated in a reaction time (RT) task in which the stimulus events consisted of two sinusoidal waves presented in close succession. The leading stimulus (S₁) had a duration of 25 msec while the binary reaction stimulus (S₂) was 250 msec. Presentation of the interstimulus interval (ISI) was irregular. S₁ as well as S₂ varied in intensity and were assigned randomly the values of 45, 68, 85 and 105 db (SPL). RT to S₂ was examined as a function of the intensity of both stimuli. Generally RT varied inversely with the intensity of S₁ and the downward gradient of RT with ISI became steepened at least for ISIs shorter than 200–250 msec. Concerning S₂, RT grew shorter as the intensity increased up to 85 db. Probably due to startle, RT tended to lengthen at S₂ = 105 db. When both S₁ and S₂ were 105 db the startle effect upon RT seemed most evident. Then the elevation in RT took place at especially those ISIs for which he fastest RTs might have been expected (about 200 msec). For the remaining intensities no interaction between S₁ and S₂ upon RT was found even for the shortest ISIs, implying that the effects of S₁ and S₂ intensities upon RT were independent.     

Short-term memory for the timing of auditory and visual signals.

Short-term memory for the timing of irregular sequences of signals has been said to be more accurate when the signals are auditory than when they are visual. No support for this contention was obtained when the signals were beeps versus flashes (Experiments 1 and 3) nor when they were sets of spoken versus typewritten digits (Experiments 4 and 5). On the other hand, support was obtained both for beeps versus flashes (Experiments 2 and 5) and for repetitions of a single spoken digit versus repetitions of a single typewritten digit (Experiment 6) when the subjects silently mouthed a nominally irrelevant item during sequence presentation. Also, the timing of sequences of auditory signals, whether verbal (Experiment 7) or nonverbal (Experiments 8 and 9), was more accurately remembered when the signals within each sequence were identical. The findings are considered from a functional perspective.     

Attending to simple auditory and visual signals

Rutgers-The State University, New Brunswick, New Jersey 08903 Is the quality of information obtained from simple auditory and visual signals diminished when both modalities must be attended to simultaneously? This question was investigated in an experiment in which subjects made forced-choice judgments of the location of simple light and tone signals presented in focused- and divided-attention conditions. The data are compared with the predictions of a model that describes the largest performance decrement to be expected in the divided-attention condition on the basis of nonattentional factors. The results of this comparison suggest that the difference in performance between focused- and dividedattention conditions is attributable solely to the increased opportunity to confuse signal with noise as the number of modalities is increased. Thus, there appears to be no evidence that dividing attention between modalities affects the quality of the stimulus representations of individual light and tone signals.     

Detection of auditory signals presented at random times

One hundred msec tones of 1000 Hz at four intensities were presented according to two Poisson schedules in a background of wide band noise and as increments to a 1000 Hz tone. Each 15 minute test session was run under fixed conditions and one of three instructions to detect the signals; the two Ss were free to respond at any time. The data analyzed were several inter-response and signal-response distributions, and they were compared with a theory due to Luce. Discrepancies between the theory and data indicate needed modifications of both the theory and the procedure.     

Social comparison on two dimensions

In this experiment social comparison on two task dimensions has been studied. The subjects received bogus feedback on their performance on two tests, one allegedly measuring creativity, the other alertness. By means of this feedback four relative position conditions were induced: scoring high on both tests, scoring low on both tests, scoring high on creativity and low on alertness, and vice versa. Anticipating either a co-operative or a competitive game, the subjects indicated their preference for one or the other task dimension and also expressed their preference for a comparison person. It was found that, as predicted, the subjects preferred and valued comparison dimensions on which they occupied a favourable position. With respect to preference for a comparison person, compensatory choices were obtained: on the dimension on which the subject performed well, they preferred an inferior other. On the dimension on which they performed poorly, they preferred a superior other. This pattern of choices was found in co-operation as well as in competition. Finally, upward preference was stronger in co-operative than in competitive conditions, particularly on the dimension on which the subject's own score was low. These and other results were discussed in relation to theoretical social comparison notions.     

On the relation between auditory spatial attention and auditory perceptual asymmetries.

Laterality investigators have typically interpreted any perceptual asymmetry as a direct expression of the functional organization of the brain. However, many other confounding factors, including the asymmetric distribution of attention, may also contribute to either the magnitude or the direction of any of these advantages. In two experiments, attention was manipulated in a dichotic listening paradigm by presenting a preexposural tone cue to the ear from which the subject was required to report. The time available to orient attention was manipulated by varying the time period between the onset of the cue and the onset of the trial (stimulus onset asynchrony, or SOA). Results indicated that a right ear advantage for the identification of verbal material obtained at a 150-msec SOA was almost completely eliminated at an SOA of 450 msec. In addition, the direction of the ear advantage for emotion identification was found to depend on task difficulty. A left ear advantage, apparent when task difficulty was minimal, was reversed to a right ear advantage when difficulty was increased. These data are taken as evidence that, when subjects are faced with a difficult dichotic task, there is a general tendency for right-handed subjects to bias their attention toward the right ear. Such a tendency is shown not only to have likely seriously compromised the results of past investigations of functional perceptual asymmetries but also to be inconsistent with previously proposed theories of dichotic listening performance.     

Spatial coding in two dimensions

There has been growing interest in exploring human performance for situations in which stimuli and/or responses vary along both horizontal and vertical dimensions. Earlier studies indicated that there is a prevalence of the horizontal dimension over the vertical dimension in the spatial codes that are used for response selection. We review evidence about spatial coding for 2-D stimulus—response sets and accounts that have been proposed for explaining how it takes place. Particular attention is devoted to the relative salience account, which provides the most comprehensive explanation of 2-D spatial coding. We also evaluate the influence of speed of spatial code formation, number of reference frames, and learning on subjects’ performance in 2-D tasks.     

Assessing the similarity of burnout dimensions in two business samples.

The concept of career burnout has been investigated in a wide variety of human services settings. Several investigations have extended the study of burnout to individuals in private sector reorganizations although burnout factors have only been derived on one sample of private sector employees. In the current research, burnout factors from previous private sector research were replicated. Results showed a strong congruency between factors from the two studies. Support was provided for rewording burnout questions from the human services scales for private sector research.     

The interaction between emotion and executive control: Comparison between visual,auditory, and tactile modalities

The reciprocal connections between emotion and attention are vital for adaptive behaviour. Previous results demonstrated that the behavioural effects of emotional stimuli on performance are attenuated when executive control is recruited. The current research studied whether this attenuation is modality dependent. In two experiments, negative and neutral pictures were presented shortly before a visual, tactile, or auditory target in a Simon task. All three modalities demonstrated a Simon effect, a conflict adaptation effect, and an emotional interference effect. However, the interaction between picture valence and Simon congruency was found only in the visual task. Specifically, when the Simon target was visual, emotional interference was reduced during incongruent compared to congruent trials. These findings suggest that although the control-related effects observed in the Simon tasks are not modality dependent, the link between emotion and executive control is modality dependent. Presumably, this link occurs only when the emotional stimulus and the target are presented in the same modality.     

Processing linguistic and perceptual dimensions of speech: interactions in speeded classification.

Performance on selective-attention and divided-attention tasks shows strong and consistent interactions when participants rapidly classify auditory stimuli whose linguistic and perceptual dimensions (the words low vs. high, low and high pitch, low and high position in space) share common labels. Compared with baseline performance, response times were greater when one or two irrelevant dimensions varied (Garner interference) and when combinations of attributes were incongruent rather than congruent (congruence effects). Performance depended only on the congruence relationships between the relevant dimension and each of the irrelevant dimensions and not on the congruence relationships between the irrelevant dimensions themselves. In selective attention, an additive multidimensional model accounts well for the patterns of both Garner interference and congruence effects.