On the relation between stimulus intensity and processing time: Piéron’s law and choice reaction time

Piéron (1914, 1920, 1952) demonstrated that simple reaction time (SRT) decays as a hyperbolic function of luminance in detection tasks. However, whether such a relationship holds equally for choice reaction time (CRT) has been questioned (Luce, 1986; Nissen, 1977), at least when the task is not brightness discrimination. In two SRT and three CRT experiments, we investigated the function that relates reaction time (RT) to stimulus intensity for five levels of luminance covering the entire mesopic range. The psychophysical experiments consisted of simple detection, two-alternative forced choice (2 AFC) with spatial uncertainty, 2 AFC with semantic categorization, and 2 AFC with orientation discrimination. The results of the experiments showed that mean RT increases with task complexity. However, the exponents of the functions relating RT to stimulus intensity were found to be similar in the different experiments. This finding indicates that Piéron’s law holds for CRT as well as for SRT. It describes RT as a power function of stimulus intensity, with similar exponents, regardless of the complexity of the task.     

Laterality effects in processing tonal and atonal melodies with affective and nonaffective task instructions

Right-handed university subjects were presented with monaural melodies that either conformed to the rules of the Western tonal system (tonal melodies) or that systematically deviated from it (atonal melodies) while containing similar contours and pitch skips. Subjects were tested under two different task instructions. One group was requested to judge whether each melody sounded correct or not (the nonaffective task); the other group had to judge whether each melody sounded pleasant or not (the affective task). The nonaffective task was found to elicit essentially no ear difference. In contrast, the affective instruction induced opposite and reliable laterality effects, depending on the valence of the response. The pleasant responses were indicative of a left hemisphere predominance and the unpleasant responses of a right hemisphere predominance. The results are consistent with the claim that the left hemisphere is biased toward positive emotions and the right to negative emotions. Moreover, the results suggest that affective appreciation of melodies is dissociable from their nonaffective judgment.     

Cognitive intrusions in a non-clinical population. I. Response style, subjective experience, and appraisal

The present study identified distinctive response styles to unpleasant cognitive intrusions to further understanding of intrusive phenomena similar to those observed in obsessive-compulsive disorder and other anxiety disorders. Response styles were studied among 125 university students who completed a questionnaire describing and evaluating seven cognitive intrusions and inventories of depressive, anxious, and compulsive symptoms. Almost all subjects (99%) reported intrusions and 92% included effortful strategies in response to intrusions in their repertoire. Large differences were observed in the dominant strategy used. Three distinctive dominant response styles were identified including no effortful response (26%) and two effortful styles, attentive thinking (34%), and escape/avoidance (40%). The two groups using effortful strategies were more anxious and reported more difficulty removing intrusions. The group using escape/avoidance strategies reported more sadness, worry, guilt, and disapproval than subjects reporting no effortful response. The attentive thinking group reported more varied forms and more frequently triggered intrusions then the no effortful response group. Within subject analyses support the group comparisons and showed that intrusions eliciting escape/avoidance strategies were evaluated more disapprovingly than thoughts eliciting attentive thinking. The results are discussed in terms of Salkovskis' (Behavior Research and Therapy, 27, 677–682, 1985) formulation of obsessive-compulsive disorder and Borkovec's (Journal of Consulting and Clinical Psychology, 23, 481–482, 1985) and Barlow's (Anxiety and its disorders: The nature and treatment of anxiety and panic, 1988) discussions of worry and generalized anxiety.     

Strategies of text retrieval: a criterion shift account.

This study scrutinized people's ability to apply different strategies to randomly intermixed immediate and delayed test items. In three experiments, participants first read one set of stories. Later, they read more stories, and after each one, answered intermixed questions about that story and one of the earlier ones. The experiments cumulatively manipulated amount of delay, test probe plausibility, probe relation (explicit, paraphrase, inference), and testing procedure (mixed versus uniform delay). Using signal detection response criterion as the index of strategy, we contrasted the single criterion hypothesis, according to which one text retrieval criterion is applied to all test items, and a multiple-criterion hypothesis. The results consistently favoured the multiple-criterion hypothesis. The results also indicated that the presence of immediate and delayed probes mutually influence one another: Less extreme signal detection criteria were adopted under mixed than uniform testing. It was concluded that text retrieval strategy is continually calibrated with reference to the quality of the test probes.     

Toward a neurophysiological theory of auditory stream segregation

Auditory stream segregation (or streaming) is a phenomenon in which 2 or more repeating sounds differing in at least 1 acoustic attribute are perceived as 2 or more separate sound sources (i.e., streams). This article selectively reviews psychophysical and computational studies of streaming and comprehensively reviews more recent neurophysiological studies that have provided important insights into the mechanisms of streaming. On the basis of these studies, segregation of sounds is likely to occur beginning in the auditory periphery and continuing at least to primary auditory cortex for simple cues such as pure-tone frequency but at stages as high as secondary auditory cortex for more complex cues such as periodicity pitch. Attention-dependent and perception-dependent processes are likely to take place in primary or secondary auditory cortex and may also involve higher level areas outside of auditory cortex. Topographic maps of acoustic attributes, stimulus-specific suppression, and competition between representations are among the neurophysiological mechanisms that likely contribute to streaming. A framework for future research is proposed.