Things I know about Things

Link between IQ and Eyes

Pupil diameter tracks changes in control state predicted by the adaptive gain theory of locus coeruleus function

Mark S. Gilzenrat | Sander Nieuwenhuis | Marieke Jepma | Jonathan D. Cohen

May, 2010 🔗

"Is it better to spend your time revising a manuscript that is likely to be published or attending a seminar on a topic that is unfamiliar but relevant to your work? The former holds well-defined prospects for reward, whereas the latter may open you up to new opportunities. This dilemma illustrates what is often referred to as the exploit/explore trade-off: whether to continue pursuing a known source of reward (exploit) or search for new ones (explore)... the locus coeruleus–norepinephrine (LC–NE) system plays an important role in this regulation."

"... revealed a close relationship between LC activity and behavioral performance indicative of shifts in control state between exploitation and exploration... a tight correlation between LC activity and pupil diameter... pupil diameter may provide a useful, noninvasive index of changes in control state..."

"The LC is a neuromodulatory nucleus, situated in the dorsal pons, with widely distributed, ascending projections throughout the forebrain that are responsible for all of the NE release in the neocortex..."

"... associated the LC–NE [locus coeruleus–norepinephrine] system with... sleep–wake cycle... recent neurophysiological studies... have suggested a more specific role for the LC–NE system in regulating the exploit/explore balance... proposing that the LC–NE system responds to changes in task utility by altering gain modulation of cortical processing mechanisms responsible for task performance, which, in turn, influences the exploit/explore balance."

"LC activity appears to exhibit two modes of function: phasic and tonic... Phasic firing typically occurs in response to task-relevant events during epochs of high performance and lower baseline LC activity... the tonic mode is associated with elevated baseline firing rate, absence of phasic responses, and degraded task performance... proposes that the phasic mode promotes exploitation, whereas the tonic mode promotes disengagement from the current task in favor of exploration..."

"NE effects can be described computationally as increased responsivity (gain modulation) of units to their inputs... when this effect is timed to task-relevant events (LC phasic mode), it facilitates execution of task-relevant processes (exploitation). However, indiscriminate uniform increases in gain (LC tonic mode) facilitate processing of stimuli and actions not relevant to the current task. This effect is akin to introducing processing noise, thereby favoring exploration..."

"... these findings suggest that pupil diameter may track instantaneous LC activity, such that baseline pupil diameter corresponds to LC tonic firing rate, and task-evoked dilations correspond to LC phasic activity... we observed that small baseline pupils were associated with better performance (i.e., fewer false alarms and shorter, less variable RTs), as well as with larger task-evoked dilations... large baseline pupils were associated with poorer performance and attenuated task-evoked dilations..."

"... peak dilations to targets did not differ between the light and dark conditions... we attempted to induce particular control states by manipulating the conflict (i.e., costs) and reward experienced by participants... manipulated the degree of conflict (high or low) experienced in... impossible-discrimination... equal... thus, discrimination was at chance... in positive feedback blocks, participants always received positive feedback to their responses... whereas in negative feedback blocks, participants always received negative feedback on these trials... Neither the main effect of conflict... nor the main effect of feedback... was significant... conflict × feedback interaction also was not significant..."

"... high-conflict/negative-feedback differed from high-conflict/positive-feedback... and low-conflict/negative-feedback... Subsequent pairwise comparisons indicated that high-conflict/negative-feedback differed from low-conflict/negative-feedback... but not from high-conflict/positive-feedback"

"The data observed prior to the escape (as task engagement presumably waned) and after the escape (as engagement built again) provide additional evidence that the pattern of pupillary responses shows a consistent relationship to control state.... we observed reliably increasing baseline pupil diameters (with a peak on the escape trial) and a trend toward diminished transient dilations (paralleling the LC tonic mode) as expected value began to decline and the participants approached a decision to escape..."

"After an escape, we observed reliably decreasing baseline pupil diameters and increasing transient dilations (paralleling the LC phasic mode). These results also replicated the hallmark finding in the classic work of Kahneman, Beatty, and others... our measure of expected value proved to be reliable in predicting pupil baseline and pupil dilation... as a predictor of pupillary dynamics, it proved superior to any other measure of performance, suggesting some validity of the measure..."

"... effect sizes obtained were generally modest, the results were consistently in line with our predictions..."

"In Experiment 1A, we used a target detection task that preserved close homology with the original work with monkeys... This experiment demonstrated the predicted inverse relationship between baseline and task-evoked pupil diameter and the relationship between pupil dynamics and behavior predicted by AGT [adaptive gain theory] if pupil diameter is indicative of LC activity. In Experiments 2 and 3, we manipulated conflict and reward in order to induce theoretically predicted changes in control state and showed that these manipulations produced the corresponding pattern of predicted pupil dynamics. Furthermore, in Experiment 3, we found that trial-to-trial changes in task utility (measured as expected value) were reliably correlated with baseline and task-evoked changes in pupil diameter and accurately predicted overt indications of task engagement and disengagement."

"... these findings provide the first evidence for a close relationship between pattern of pupillary response and control state, suggesting that pupillometry may provide a useful index of control state in future research... two additional inferences can be made from our findings: (1) Pupillary responses track LC activity in humans in a manner similar to that observed in monkeys, and (2) on the basis of this, changes in task utility are associated with changes in LC activity and control state predicted by AGT... "

"Both the pupil... and the LC... have traditionally been cast as mechanisms related to arousal. Because this article proposes a close relationship between the two and draws on AGT to relate them to behavior, the question arises as to how AGT relates to arousal theory... arousal impacts performance by restricting attentional selection... if arousal increases too much, selection becomes so restricted that some task-relevant cues fail to be processed, resulting in impaired performance..."

"... AGT associates high arousal (the LC tonic mode) with indiscriminate (vs. task-selective)... indiscriminate increase in gain increases the chances that task-irrelevant information will be processed... compete with task-relevant information for control of behavior..."

"... from an ecological perspective, the adaptiveness of the high-arousal state has been neglected... under high-arousal conditions, thorough information processing is sacrificed for quick action, self-preservation behavior, and efficient selection of alternate behaviors... is consistent with an account of the adaptiveness of the LC tonic mode in terms of disengagement and exploration...

"... found a significant difference in the mean pupil diameter during problem solving as a function of items that were correctly solved vs. those answered incorrectly... a smaller pupil response for tasks that overload participants as compared to tasks that participants successfully perform with very high load."

"A vast body of research has evolved from the theoretical framework put forward by Cattell, who developed the Culture-Fair IQ Test (CFT 20-R) to assess fluid intelligence."

"... researchers from various fields have investigated individual differences that contribute to fluid intelligence... including participants' reports of strategies [4] or motivational factors (e.g. effort [5, 6])... psychophysiological measures, especially ocular movements like scanpaths [8] and pupil diameter [9] have shown to be useful indices for strategies and motivational factors to predict individual differences in fluid intelligence..."

"Bornemann and colleagues have investigated 11th graders and found a significant positive correlation between task difficulty and pupil dilation for an analogy task that participants were unfamiliar with, but not for an algebra task that was already part of the curriculum [20]. They concluded that the novelty of the task allows participants with greater cognitive abilities to allocate more cognitive resources, whereas a familiar task does not cause this effect. Overall, there seems to be a complex interplay between task difficulty and pupil diameter that varies with task type, novelty, and intelligence."

"The authors found that a significant percentage of the variance on the participants' scores on a Raven's Advanced Progressive Matrices test was explained by eye-fixation patterns, where systematic scanning of the problem matrices and less toggling between matrix and responses were indicative of better performance, which likely reflects differential strategies between groups..."

"With regard to the pupil diameter size, we found a highly significant difference between the the items that were solved correctly and those which were not. As shown in Table 2, participants showed a larger pupil diameter size in the case of correctly solved test items as compared to those items that were answered incorrectly."

"... participants performed significantly less saccades for test items that were correctly solved than for those CFT items that they answered incorrectly. Additionally, in the case of correctly solved items, the participants performed saccades with significantly larger amplitude and longer duration... a strong positive correlation between saccade peak velocity and performance in fluid intelligence tasks."

Do your eye movements reveal your performance on an IQ test? A study linking eye movements and socio-demographic information to fluid intelligence

March 29, 2022 🔗