Pupillary responses index cognitive resource limitations

Abstract

Cognitive task-evoked pupillary responses reliably index information-processing loads. However, previous studies have reported inconsistent findings regarding the nature of the pupillary response when processing demands approach or exceed available processing resources. This condition was examined in 22 normal undergraduates by using pupillometric recordings during a digit span recall task, with 5 (low load), 9 (moderate load), and 13 (excessive load) digits per string. Pupillary responses increased systematically with increased processing load (to-be-recalled digits) until the limit of available resources (memory capacity of 7 +/- 2 digits), when they reached asymptote and then declined with resource overload (> 9 digits). These findings suggest that pupillary responses increase systematically with increased processing demands that are below resource limits, change little during active processing at or near resource limits, and begin to decline when processing demands exceed available resources.

Pupillary assessment and computational modeling of the Stroop task in depression

“…For example, as individuals are asked to remember larger number of digits, for example, pupil dilation increases proportionally (e.g. Kahneman and Beatty, 1966;Granholm et al, 1996). Thus, the pupil has been shown to reflect the time course of activity in brain areas associated with cognitive processing such as the dorso-lateral prefrontal cortex (Siegle et al, 2003b).…”

Pupillary and reaction time measures of sustained processing of negative information in depression

“…As individuals are asked to remember larger numbers of digits, for example, their pupils reliably dilate (e.g., Granholm et al 1996;Kahneman and Beatty 1966). Pupil dilation has also been observed to increase with the difficulty of mental arithmetic (Ahern and Beatty 1979;Hess and Polt 1964).…”

Assessment of a User’s Time Pressure and Cognitive Load on the Basis of Features of Speech

“…16 One way of understanding the better results for Experiment 2 is simply to note that the indicators shown in Figures 6 through 10 tend to occur to a greater extent in Experiment 2 (i.e., the lines in the right-hand graphs in these figures tend to be higher than those in the left-hand graphs). Since these indicators are on the whole low-frequency events, any increase in their frequency is likely to make recognition more accurate.…”

“…The diameter of a person's pupil has likewise been shown to vary systematically as a function of mental load-although it is also strongly affected by other factors, such as ambient illumination and the distance of objects being fixated (see, e.g., [16]). These other factors would be especially problematic with mobile systems.…”