Influence of correlated visual cues on auditory signal detection

Two experiments investigated the effects on auditory signal detection of introducing visual cues that were partially correlated with the signal events. The results were analyzed in terms of a detection model that assumes that such cue-signal correlations will not affect sensitivity, but will instead cause the subject to develop separate response biases for each cue. The model specifies a functional relationship between the asymptotic values of these cuecontingent biases. The overall results of the experiments supported the detection assumptions of the model and the general bias learning assumption, but indicated a more complex learning process than that specified by the model.     

Congruency reversals in an accessory signal Simon task with auditory and visual stimuli

In visual two-choice reaction-time tasks, a Simon-like effect occurs when a peripheral accessory signal is presented shortly before or together with the response signal. However, the effect reverses when the peripheral signal appears shortly after the response signal. This pattern also occurs when the peripheral signal appears relative to a go (nogo) signal, with the relevant signal presented well in advance. The reversal has been explained as the inhibition of exogenous response-code activation as soon as an action plan has been developed. In three experiments we investigated whether the inhibition also occurred with auditory and crossmodal stimuli. A Simon effect appeared in all experiments, but the reversal only occurred when peripheral and relevant response signals were auditory, and not when the relevant and irrelevant signals were in a different modality. We suggest that planned actions are protected against exogenous interference by a modality-specific inhibitory process, determined by the relevancy of the modality of the peripheral accessory signal.     

Operator behavior in a dynamic visual signal detection task

The effects of changes in signal-to-noise ratio (SIN) and feedback state on the operator’s detection behavior, particularly derived operator thresholds, were investigated using a discrete visual signal. It was found that: (1) the operator behaves as if he has established different thresholds as a function of S/N; (2) his decision thresholds are relatively independent of the presence or absence of feedback; and (3) the operator will change his threshold accordingly for a change from one S/N to another. A model of the operator’s behavior, which introduced the concept of “operator” noise. yielded predictions of detection and false alarm probabilities which were extremely close to the observed values.     

Decision-related cortical potentials during an auditory signal detection task with cued observation intervals.

Cortical-evoked potentials were recorded from human subjects performing an auditory detection task with confidence rating responses. Unlike earlier studies that used similar procedures, the observation interval during which the auditory signal could occur was clearly marked by a visual cue light. By precisely defining the observation interval and, hence, syncrhonizing all perceptual decisions to the evoked potential averaging epoch, it was possible to demonstrate that high-confidence false alarms for accompanied by late-positive P3 components equivalent to those for equally confident hits. Moreover the hit and false alarm evoked potentials were found to covary similarily with variations in confidence rating and to have similar amplitude distributions over the scalp. In a second experiment wherein the signal intensity was increased to make signal presence and signal absence clearly discriminable and the a priori probability of signal presentation was varied from .5 to .9, it was demonstrated that correct rejections can be associated with a P3 component larger than that for hits. Thus it was possible to show, within the signal detection paradigm, how the two major factors of decision confidence and expectancy are reflected in the P3 component of the cortical-evoked potential.     

The effect of cueing in a visual signal detection task

In a signal detection task four subjects were presented with stimulus cards, 50% of which contained a capital O in one of the four quadrants. Fifty per cent of these Os were surrounded by a small rectangle. This small rectangle served as a simultaneous cue, indicating the region where the O could appear. The other 50% were surrounded by a big rectangle encompassing the whole field. Fifty per cent of the blank cards contained a small rectangle, the other 50% a big one. Exposure duration was set at 15 and 20 ms. The results indicated that subjects, for whom these exposure durations led to performance exceeding chance level, used the simultaneous cue for reducing the field to be searched, resulting in higher sensitivity (d') in the small rectangle condition. Results were interpreted in terms of increasing efficiency of search as a result of which a higher quality of the icon was available for making decisions about the presence of the O.     

Sex composition and group performance in a visual signal detection task

Forty-eight Ss (24 males, 24 females) were run in groups of 4 on 720 trials of a 16-alternative forced-choice visual signal detection task requiring both individual and group decisions. Four types of groups were formed: all male, all female, mixed-alternate (seated in the order male-female-male-female), and mixed-adjacent (seated in the order male-male-female-female). There were no differences in performance between all-male and all-female groups, but mixed-sex groups had poorer performance, with mixed-adjacent groups having significantly lower sensitivity than homogeneous-sex groups. The results were interpreted as indicating that heterogeneity of groups with regard to sex interacts with seating pattern in affecting performance, probably due to the formation of information coalitions between like-sex group members when the seating pattern encourages such coalitions.     

Effects of signal to noise variability over repeated sessions in an auditory vigilance task

Subjects listened to a sequence of Gaussian noise pulses of 0.5-sec duration, occurring at 2.5-sec intervals. Performance was compared under two conditions: One group detected the occurrence of a 1.8-dB increment in noise pulses; a second group detected the occurrence of increments of 1.3, 1.8, or 2.3 dB. All Ss performed for three 90-min sessions on different days The usual trends were noted for hits and false alarms. TSD indices, d’ and β were also derived. For both groups, it was found that d′ increased slightly over sessions and decreased almost negligibly during sessions, and criterion indices, β generally increased slightly both within and over sessions. Performance was generally comparable under the fixed- and mixed-signal conditions.     

阈下情绪启动对认知任务转换的影响

阈下情绪启动是最近热点问题之一。本研究通过两个实验考察了阈上和阈下情绪图片所诱发的情绪状态对任务转换的影响。实验一对28名被试分别阈上启动三种情绪,发现积极和消极情绪对任务转换有一定的影响,但积极情绪与消极情绪两者对任务转换影响的差异不显著。实验二对32名被试分别阈下启动三种情绪,并完成相应的数字任务,发现三种情绪下的转换损失无显著性差异。以上结果表明阈上和阈下刺激所诱发的情绪对任务转换影响机制是有差异的。     

Critical-band effects in two-channel auditory signal detection

Two-channel auditory signal detection was investigated with 50-msec sinusoidal signals masked by binaurally uncorrelated noise. In the two-channel tasks, the signals in each earphone channel were presented with an independent probability during the single observation interval and the observers were required to detect the inputs in a single earphone (selective-attention condition) or in both earphones (divided-attention condition). When the signals in each earphone were within the same critical band (the assumed singled processing unit in frequency domain), there was a decrement in detection performance in both the selective- and divided-attention (i.e. dichotic) conditions compared with the monaural condition. However, when signals were separated in frequency by several critical bands, a decrement in dichotic performance, as compared with monaural performance, occurred only in the divided-attention condition. These findings are discussed in terms of their implications regarding models of multichannel signal processing and the definition of input channels in terms of earphones.     

The effect of auditory and visual models on acquisition of a timing task

While research on observational learning has typically employed visual models of correct performance, the characteristics of perceptual systems support the suggestion that an auditory model may be more effective in developing a cognitive representation of tasks for which timing is essential. Therefore, it was the purpose of this study to compare the relative effectiveness of auditory and visual models in the acquisition of a timing task. Subjects were provided with an auditory model, a visual model, a combined auditory and visual model, or no model of correct performance. There were significant main effects of groups and trials during acquisition. While performance of all groups improved during acquisition, the audio and audiovisual groups had generally better performance. The same effects were significant on immediate transfer, again reflecting the superior performance of the two auditory model groups. The results suggest an important role for audition in the development of a cognitive representation of movement timing.     

Respiratory phase and visual signal detection

Previous studies have implicated respiration as a source of intra-S variation in visual signal detection tasks. In the present study, pneumographic respiration records were obtained on 22 female undergraduates during a visual signal detection task. The analysis of signal detection with respect to respiration phase showed that signals presented during exhalation were detected more frequently than those presented during inhalation. These findings suggest that the intra-S variation in signal detection performance may be partially accounted for by respiratory behavior at the moment of signal presentation.     

Residual sensory capacities of the deaf: a signal detection analysis of a visual discrimination task.

This experiment compared the visual sensory sensitivity of deaf and hearing subjects in a signal detection paradigm. Subjects (ns = 6) were required to give forced-choice responses to a brightness discrimination task under three stimulus probability conditions (0.25, 0.50, and 0.75). A total of 1,800 trials were given to each subject and utilized to construct isosensitivity functions and d' and Beta, indices for sensory sensitivity and response bias, respectively. The results showed that no enhanced sensory sensitivity is present for these deaf children and questions the classical sensory compensation hypothesis. Furthermore, the deaf subjects responded in a relatively bias-free manner to variations in stimulus probability.     

Effect of interval between auditory and preceding visual stimuli on auditory sensitivity

Auditory thresholds were determined by a modified method of limits, in introverts, ambiverts and extraverts, under three intensities of light. Five determinations were made: one before, one during and three (30 sec., c. 8 and 16 min.) after the light stimulation. An analysis of variance of the data showed significant results for the interval conditions, the personality type and the interaction of these parameters, under the weak light. Interval effects were also significant under medium and strong light. A weak light increased, and a strong light decreased, auditory sensitivity when threshold determinations began 30 sec., but not more than about 8 min., after the light stimulation, in introverts.