Stimulus information and processing time in pitch perception

Summary The assumption of Massaro, that the preperceptual auditory image is processed at the same rate as the stimulus information, was tested for pitch recognition, using a recognition masking paradigm. The data clearly show that the preperceptual image is processed with a much lower rate.     

Stimulus control of information processing in pigeon short-term memory

Six pigeons were trained initially on a delayed successive matching-to-sample task using red and green fields as sample and test stimuli. Following acquisition, each sample was followed either by a vertical line (“remember” cue), which indicated that sample memory would be tested, or by a horizontal line (“forget” cue), which indicated that sample memory would not be tested. During the experiments, sample memory on forget trials was tested occasionally. A series of five experiments revealed: (a) better retention on remember trials than on forget trials, (b) increased effectiveness of a forget cue when it followed closely sample offset, (c) more rapid forgetting over a retention interval ranging from 3 to 6 sec on forget trials than on remember trials, (d) a “cancellation” effect in which a remember cue which followed immediately the offset of a forget cue attenuated markedly the effectiveness of the forget cue, and (e) an “insulation” effect in which the effectiveness of a forget cue was reduced considerably when presented after a remember cue. It was concluded that pigeons actively process or rehearse the sample memory during the retention interval.     

Stimulus information vs processing time in auditory pattern recognition

Previous studies have shown that pitch perception improves with increases in tone duration. An increase in tone duration increases the information available in the stimulus presentation. Other recent experiments have shown that sufficient perceptual processing time is also necessary for accurate pitch perception. The present study determines the relative contribution of stimulus information and processing time in an absolute pitch indentification task. The results indicate that processing time is more critical than stimulus information. The results are described accurately by a model that describes the perceptual process in terms of the information in the stimulus and the time the information is available for perceptual processing.     

Stimulus processing constraints in audition

In 3 experiments, the authors tested performance in simple tone matching and classification tasks. Each tone was defined on location and frequency dimensions. In the first 2 experiments, participants completed a same-different matching task on the basis of one of these dimensions while attempting to ignore irrelevant variation in the other dimension. In Experiment 3, in which the tones were classified either by frequency or location, the authors explored intertrial repetition effects. The patterns of performance across these different tasks were remarkably similar and were taken to reveal basic characteristics of stimulus encoding processes. The data suggest a processing sequence in audition that reveals an early stage in which location and frequency are treated as being integral and a latter stage in which location and frequency are separable.     

Stimulus intensity and foreperiod effects in intersensory facilitation

Intersensory facilitation refers to the more rapid reaction time (RT) to a target in one modality and an accessory stimulus in a different modality compared to a RT to the target alone. Prior studies suggest two processes contribute to the phenomenon, termed the preparatory state and energy integration which refer to the action of accessory stimulation in providing forewarning and intensifying the reaction signal, respectively. Experiment I factorially varied foreperiod duration, light (target) intensity and tone (accessory) intensity in a discriminative RT task. The results were that foreperiod (preparatory state) and intensity (energy integration) effects were additive, implying that they affected separate processing stages. Accessory stimulus intensity affected false alarm rate on catch trials. This suggests that energy integration involves a form of response bias (increased likelihood of responding) and not facilitation (more rapid information processing). Experiment II indicated that comparable energy integration effects obtain with tone as target and light as accessory, as well as vice versa. The findings further indicated that RT to a bisensory pairing is more rapid when attention is directed to the more potent member of the pair.     

Stimulus intensity control and personality: A research note

Previous research has suggested that variations in augmenting-reducing, extraversion, and sensation seeking might be explained in terms of a common stimulus intensity control mechanism. However, empirical tests of this hypothesized relationship have produced equivocal findings. The present study attempts to clarify the issue by analyzing scores for extraversion, sensation seeking, and both cortical and questionnaire measures of augmenting-reducing obtained from the same sample of subjects. Apart from a significant positive correlation between the questionnaire index of reducing and sensation seeking, which have not previously been investigated, the results show no evidence of a systematic relationship among the variables.     

Stimulus variability and processing dependencies in speech perception

Processing dependencies in speech perception between voice and phoneme were investigated using the Garner (1974) speeded classification procedure. Variability in the voice of the talker and in the cues to word-initial consonants were manipulated. The results showed that the processing of a talker's voice and the perception of voicing are asymmetrically dependent. In addition, when stimulus variability was increased in each dimension, the amount of orthogonal interference obtained for each dimension became significantly larger. The processing asymmetry between voice and phoneme was interpreted in terms of a parallel-contingent relationship of talker normalization processes to auditory-to-phonetic coding processes. The processing of voice information appears to be qualitatively different from the encoding of segmental phonetic information, although they are not independent. Implications of these results for current theories of speech perception are discussed.     

Stimulus intensity effects on auditory and visual reaction processes.

Literature on the effect of stimulus intensity on reaction processes was reviewed. It was shown that there is no agreement as to whether intensity effects are limited to encoding or whether they are extended to later processing stages. The situation can be characterized as an asymmetry between modalities: vision is consistent with the first alternative and audition with the second.Chronometric analysis was used to bear on the question. It was shown that the effects of visual intensity and foreperiod (FP) are additive in a simple RT situation both for constant and mixed blocks FP. Auditory intensity and FP interact in both simple and two-choice situations. In a control experiment visual intensity and S-R compatibility were found to be additive. The asymmetry was accounted for by auditory alerting, previously discussed by several authors.The framework of stimulus intensity research utilizing RT measures was briefly evaluated.     

Stimulus and response conflict processing during perceptual decision making

Encoding and dealing with conflicting information is essential for successful decision making in a complex environment. In the present fMRI study, stimulus conflict and response conflict are contrasted in the context of a perceptual decision-making dot-motion discrimination task. Stimulus conflict was manipulated by varying dot-motion coherence along task-relevant and task-irrelevant dimensions. Response conflict was manipulated by varying whether or not competing stimulus dimensions provided evidence for the same or different responses. The right inferior frontal gyrus was involved specifically in the resolution of stimulus conflict, whereas the dorsal anterior cingulate cortex was shown to be sensitive to response conflict. Additionally, two regions that have been linked to perceptual decision making with dot-motion stimuli in monkey physiology studies were differentially engaged by stimulus conflict and response conflict. The middle temporal area, previously linked to processing of motion, was strongly affected by the presence of stimulus conflict. On the other hand, the superior parietal lobe, previously associated with accumulation of evidence for a response, was affected by the presence of response conflict. These results shed light on the neural mechanisms that support decision making in the presence of conflict, a cognitive operation fundamental to both basic survival and high-level cognition.     

Stimulus processing during apparent unconsciousness in anesthetized volunteers

Return of motor-responses upon request as an indicator of stimulus processing during apparent unconsciousness in general anesthesia was studied in 8 healthy, male volunteers during prolonged inhalation of nitrous oxide. First the minimal effective concentration of nitrous oxide was established for each volunteer, based upon continued absence of motor-responses to repeated verbal commands. One week later this concentration of nitrous oxide was administered for a 3-hr. period; return of motor-responses after at least 30 min. of absence was considered a sign of so-called unconscious perception. Four volunteers showed return of motor-response within the 3 hr. of exposure, but two of these had been rather restless throughout the session. Results indicate that unexpected processing of information by patients may occur during presumed unconsciousness after a prolonged inhalation of nitrous oxide in general anesthesia.     

Stimulus information and stimulus interference in bisensory short-term memory

An attempt was made to determine if Ss’ strategy of retaining stimulus material changed under conditions of bisensory simultaneous stimulation when one of the two inputs was relevant information as opposed to interference. Thus in Group 1 Ss were stimulated bisensorily, attended to both inputs (information), but recalled only one input. Ss in Group 2 were stimulated bisensorily, attended to only one input, and recalled only that input (interference). It was found that S’s efficiency of recall was decreased in the information condition (Group 1) but strategy was not altered. In both groups, Ss performed similarly; performance was in turn similar to that observed in the typical bisensory situation, i.e., where both channels are recalled.     

Stimulus information and primate discrimination learning: The influence of postresponse stimulus information

This paper describes an experiment concerned with the operation of discriminatory processes subsequent to an individual's overt choice response and how these may be affected by extrinsic stimulus information. The experiment used subhuman primates and was conducted within the simultaneous two-choice visual discrimination paradigm. The major results of the experiment indicated that: (1) learning performance may be significantly interfered with by irrelevant postresponse stimulus information, and (2) this interference is primarily associated with the presentation of irrelevant information subsequent to nonreinforced choice responses. The results are discussed in terms of the relation between the occurrence of reinforcement and the operation of memory storage processes.