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Perception likely results from the interplay between sensory information and top-down signals. In this electroencephalography (EEG) study, we utilised the hierarchical frequency tagging (HFT) method to examine how such integration is modulated by expectation and attention. Using intermodulation (IM) components as a measure of nonlinear signal integration, we show in three different experiments that both expectation and attention enhance integration between top-down and bottom-up signals. Based on a multispectral phase coherence (MSPC) measure, we present two direct physiological measures to demonstrate the distinct yet related mechanisms of expectation and attention, which would not have been possible using other amplitude-based measures. Our results link expectation to the modulation of descending signals and to the integration of top-down and bottom-up information at lower levels of the visual hierarchy. Meanwhile, the results link attention to the modulation of ascending signals and to the integration of information at higher levels of the visual hierarchy. These results are consistent with the predictive coding account of perception. [ABSTRACT FROM AUTHOR]

A debate has emerged as to whether recognition of emotional stimuli is more accurate or more biased than recognition of nonemotional stimuli. Teasing apart changes in accuracy versus changes in bias requires a measurement model. However, different models have been adopted by different researchers, and this has contributed to the current debate. In this article, different measurement models are discussed, and the signal detection model that is most appropriate for recognition is adopted to investigate the effects of valence and arousal on recognition memory performance, using receiver operating characteristic analyses. In addition, complementary two-alternative forced choice experiments were conducted in order to generalize the empirical findings and interpret them under a relatively relaxed set of measurement assumptions. Across all experiments, accuracy was greater for highly valenced stimuli and stimuli with high arousal value. In addition, a bias to endorse positively valenced stimuli was observed. These results are discussed within an adaptive memory framework that assumes that emotion plays an important role in the allocation of attentional resources. [ABSTRACT FROM AUTHOR]

This study applied specific aspects of signal detection theory (target salience and decision payoffs) to examine the associations among measured attention and accuracy on a stimulus discrimination task patterned after prescription checking. 85 participants completed the d2 Test of Attention and were assigned to either a control condition with general task instructions or a payoff condition with points accumulated or lost based on ultimate performance. Participants checked simulated product order forms for clerical errors for 40 mm. The stimulus set included errors that varied with respect to their ease of detection or salience. Analysis indicated that measured attention was related to performance accuracy and speed as expected. Also decision payoffs significantly increased accuracy on the discrimination task regardless of target salience and discrimination accuracy decreased as the salience of the stimulus mismatches decreased. Implications for real-world applications of signal detection theory to tasks such as prescription checking are explored. [ABSTRACT FROM AUTHOR]

The authors explored the temporal mechanism of attention deficit in children with attention-deficit/ hyperactivity disorder (ADHD). In rapid serial visual presentation tasks in which two targets (T1 and T2) were presented in close temporal proximity among distractors, participants tried to identify T1 and detect T2 in one (dual-task) experiment and only to detect T2 in a second control (single-task) experiment. The sensitivity of T2 detection was analyzed using signal detection theory. The attentional blink-the impairment in T2 detection following the identification of T1 -- was increased in magnitude and protracted in the patients. Moreover, some ADHD children appeared to have a blink largely normal in magnitude but temporally displaced toward a later time. The authors hypothesize that a slower closing of the attention gate may mediate this specific attention impairment in ADHD children. [ABSTRACT FROM AUTHOR]

Describes the classical similarity-choice and signal-detection theories and relates them to current theories of categorization, Garner tasks, visual search, cuing procedures, task switching, and strategy choice. Information on similarity-choice theory; Details of signal-detection theory; Executive control of attention.

Animal models of human cognitive processes are essential for studying the neurobiological mechanisms of these processes and for developing therapies for intoxication and neurodegenerative diseases. A discrete-trial signal detection task was developed for assessing sustained attention in rats; a previous study showed that rats perform as predicted from the human sustained attention literature. In this study, we measured the behavior of humans in a task formally homologous to the task for rats, varying two of the three parameters previously shown to affect performance in rats. Signal quality was manipulated by varying the increment in the intensity of a lamp. Trial rate was varied among values of 4, 7, and 10 trials/min. Accuracy of signal detection was quantified by the proportion of correct detections of the signal (P(hit)) and the proportion of false alarms (P(fa), i.e. incorrect responses on non-signal trials). As with rats, P(hit) in humans increased with increasing signal intensity whereas P(fa) did not. Like rats, humans were sensitive to the trial rate, though the change in behavior depended on the sex of the subject. These data show that visual signal detection behavior in rats and humans is controlled similarly by two important parameters, and suggest that this task assesses similar processes of sustained attention in the two species. [Copyright &y& Elsevier]

It has been suggested that perceptual hallucination results from a bias in attributing a self-generated event to an external source. The ‘self-monitoring’ model proposes that the impairment arises from a defective corollary discharge in perceptual decisions. However, psychophysical studies in schizophrenia patients have not found consistent support for the model. We re-explored this issue by including subjects with mood disorders as patient controls and employed signals of variable intensities in an auditory detection and discrimination task. Using signal detection theory, we found decreased sensitivity in auditory detection and discrimination in schizophrenia patients, as compared to control subjects. Moreover, the psychometric functions of schizophrenics had a shallower slope than those of the controls. According to the uncertainty theory of signal detection, this suggested that schizophrenia patients monitored a smaller number of perceptual channels. On the other hand, hallucinating and non-hallucinating schizophrenia patients did not differ from each other, nor did they as a group differ from control subjects in terms of response bias. Overall, our results do not support the idea that hallucination results from an altered bias in the on-line processing of perceptual signals. [Copyright &y& Elsevier]

Examines the demonstration of robust stimulus-driven, attentional processes in selective frequency listening in signal-detection experiments. Detection of signal tones; Frequency of an uninformative cue tone; Implications for models of auditory attention.