Pupil size is correlated with a wide variety of important cognitive variables and is increasingly being used by cognitive scientists. Pupil data can be recorded inexpensively and non-invasively by many commonly used video-based eye-tracking cameras. Despite the relative ease of data collection and increasing prevalence of pupil data in the cognitive literature, researchers often underestimate t...

Task preparation involves multiple component processes, including a general evaluative process that signals the need for adjustments in control, and the engagement of task-specific control settings. Here we examined the dynamics of these different mechanisms in preparing the attentional control system for visual search. We explored preparatory activity using pupil dilation, a well-established m...

What is the cause of perceptual switching of ambiguous stimuli? Although local competition between stimulus-specific representations can explain bistable perception dynamics (1), Einhäuser et al. (2) argue that norepinephrine (NE) release in the locus coeruleus (a nonperceptual structure) could play a critical role in perceptual bistability. They reported an NEmediated increase in pupil diamete...

Relative afferent pupillary defects were simulated in normal individuals by performing the alternating light test while dimming the light in front of one eye with neutral density filters. Pupillary responses were elicited using a binocular photostimulator and recorded using a binocular television pupillometer. In five subjects, four spatial variables of the pupillary response--contraction ampli...

Pupil diameters of color-grapheme synaesthetes were measured with an infrared eye-tracker while Stroop-like alphanumeric symbols were passively viewed. Pupils dilated more when synaesthetes viewed incongruently-colored symbols than congruently-colored symbols or symbols printed in the standard black ink. The results show that the physiological measure of pupillary diameter can be used as a mark...

BACKGROUND Schools have the potential to influence their pupils' behaviour through the school's social organisation and culture, as well as through the formal curriculum. This paper provides the first attempt to explain the differences between schools in rates of reported heterosexual sexual experience amongst 15 and 16 year olds. It first examined whether variations in rates of sexual experien...

Constricted affect (CA) is a cardinal negative symptom of schizophrenia-spectrum disorders. It is unclear whether behaviorally-defined CA occurs in individuals with schizotypy-those with the personality organization reflective of schizophrenia liability. Moreover, it is unclear whether CA contributes to real world dysfunction in this population. The present study employed computerized prosodic ...

In reading research, a longstanding question is whether any stages of lexical processing require central attention, and whether such potential demands are frequency-sensitive. In the present study, we examined the allocation of cognitive effort in lexical processing by examining pupil dilations and naming latencies in a modified delayed naming procedure. In this dual-task/change procedure, part...

We used diffraction modulation transfer functions and model eyes to predict the effect of defocus on the contrast sensitivity function (CSF) and compared these predictions with previously published experimental data. Using the principle that optically induced changes in the modulation transfer function should be paralleled by identical changes in the CSF, we used the modulation transfer functio...

Two patients are presented with respiratory depression for which no cause was apparent. Both had ingested narcotics without the parents' knowledge. Narcotic ingestion should be suspected if signs of respiratory failure with constricted pupils are present, and a diagnostic test with naloxone should be performed.