The neural correlates of rapid eye movements (REMs) in sleep are extraordinarily robust; including REM-locked activation in the retrosplenial cortex, the supplementary eye field and areas overlapping cholinergic basal nucleus. The phenomenology of REMs speaks to the notion that perceptual experience in both sleep and wakefulness is a constructive process – in which we generate predictions of sensory inputs and then test those predictions through actively sampling the sensorium with eye movements. On this view, REMs during sleep may index an (...) internalized active sampling or ‘scanning’ of self-generated visual constructs that are not constrained by visual input. If this view is correct, it renders REMs an ideal probe to study consciousness as “an exclusively internal affair” (Metzinger 2009). In other words, REMs offer a probe of active inference – in the sense of predictive coding – when the brain is isolated from the sensorium in virtue of the natural blockade of sensory input during REM sleep. REMs are temporally precise events that enable powerful inferences based on timeseries analyses. As a natural, task-free probe, [REMs] could be used in non-compliant subjects, including infants and animals. In short, REM constitutes a promising probe to study the ontogenetic and phylogenetic development of consciousness and perhaps its abnormal development in schizophrenia and autism, which have been considered in terms of aberrant predictive coding. (shrink)

People often make use of a spatial “mental time line” to represent events in time. We investigated whether the eyes follow such a mental time line during online language comprehension of sentences that refer to the past, present, and future. Participants' eye movements were measured on a blank screen while they listened to these sentences. Saccade direction revealed that the future is mapped higher up in space than the past. Moreover, fewer saccades were made when two events are simultaneously taking (...) place at the present moment compared to two events that are happening in different points in time. This is the first evidence that oculomotor correlates reflect mental looking along an abstract invisible time line during online language comprehension about time. Our results support the idea that observing eye movements is likely to “detect” invisible spatial scaffoldings which are involved in cognitively processing abstract meaning, even when the abstract meaning lacks an explicit spatial correlate. Theoretical implications of these findings are discussed. (shrink)

This study investigates how speed of motion is processed in language. In three eye-tracking experiments, participants were presented with visual scenes and spoken sentences describing fast or slow events (e.g., The lion ambled/dashed to the balloon). Results showed that looking time to relevant objects in the visual scene was affected by the speed of verb of the sentence, speaking rate, and configuration of a supporting visual scene. The results provide novel evidence for the mental simulation of speed in language and (...) show that internal dynamic simulations can be played out via eye movements toward a static visual scene. (shrink)

We know that reading involves coordination between textual characteristics and visual attention, but research linking eye movements during reading and comprehension assessed after reading is surprisingly limited, especially for reading long connected texts. We tested two competing possibilities: (a) the weak association hypothesis: Links between eye movements and comprehension are weak and short‐lived, versus (b) the strong association hypothesis: The two are robustly linked, even after a delay. Using a predictive modeling approach, we trained regression models to predict comprehension scores (...) from global eye movement features, using participant‐level cross‐validation to ensure that the models generalize across participants. We used data from three studies in which readers (Ns = 104, 130, 147) answered multiple‐choice comprehension questions ~30 min after reading a 6,500‐word text, or after reading up to eight 1,000‐word texts. The models generated accurate predictions of participants' text comprehension scores (correlations between observed and predicted comprehension: 0.384, 0.362, 0.372, ps <.001), in line with the strong association hypothesis. We found that making more, but shorter fixations, consistently predicted comprehension across all studies. Furthermore, models trained on one study's data could successfully predict comprehension on the others, suggesting generalizability across studies. Collectively, these findings suggest that there is a robust link between eye movements and subsequent comprehension of a long connected text, thereby connecting theories of low‐level eye movements with those of higher order text processing during reading. (shrink)

A controversial claim in recent dual process accounts of reasoning is that intuitive processes not only lead to bias but are also sensitive to the logical status of an argument. The intuitive logic hypothesis draws upon evidence that reasoners take longer and are less confident on belief–logic conflict problems, irrespective of whether they give the correct logical response. In this paper, we examine conflict detection under conditions in which participants are asked to either judge the logical validity or believability of (...) a presented conclusion, accompanied by measures of eye movement and pupil dilation. The findings show an effect of conflict, under both types of instruction, on accuracy, latency, gaze shifts, and pupil dilation. Importantly, these effects extend to conflict trials in which participants give a belief‐based response (incorrectly under logic instructions or correctly under belief instructions) demonstrating both behavioral and physiological evidence in support of the logical intuition hypothesis. (shrink)

In two experiments, participants solved anagram problems while their eye movements were monitored. Each problem consisted of a circular array of five letters: a scrambled four-letter solution word containing three consonants and one vowel, and an additional randomly-placed distractor consonant. Viewing times on the distractor consonant compared to the solution consonants provided an online measure of knowledge of the solution. Viewing times on the distractor consonant and the solution consonants were indistinguishable early in the trial. In contrast, several seconds prior (...) to the response, viewing times on the distractor consonant decreased in a gradual manner compared to viewing times on the solution consonants. Importantly, this pattern was obtained across both trials in which participants reported the subjective experience of insight and trials in which they did not. These findings are consistent with the availability of partial knowledge of the solution prior to such information being accessible to subjective phenomenal awareness. (shrink)

The issues the commentators have raised and which we address, include: the debate over how attention is allocated during reading; our distinction between early and late stages of lexical processing; our assumptions about saccadic programming; the determinants of skipping and refixations; and the role that higher-level linguistic processing may play in influencing eye movements during reading. In addition, we provide a discussion of model development and principles for evaluating and comparing models. Although we acknowledge that E-Z Reader is incomplete, we (...) maintain that it provides a good framework for systematically trying to understand how the cognitive, perceptual, and motor systems influence the eyes during reading. (shrink)

The focus of this chapter is the relationship between synaesthesia, attention and eye movements. The measurement of eye movements as a core experimental tool for gaining insight into complex cognitive processes in general and attentional mechanisms more specifically, is now firmly established. By means of eye movements, the neural basis of higher cognitive processes, such as target selection, working memory, and response suppression, can be investigated. It therefore seems logical that eye movement recordings can also be used to investigate a (...) complex phenomenon like synaesthesia. In this chapter, we will start with a section summarizing the relationship between eye movements and attention in general. Then the focus moves to synaesthesia and what we currently know about synaesthesia based on the method of measuring eye movements. Finally, we discuss pupillometry which provides a window on changes in the 'allocation' of attention and the 'consolidation' of perception. Consequently, it offers a useful technique for probing 'changes' in mental states due synaesthetic perceptions. (shrink)

We explore the idea that eye-movement strategies in reading are precisely adapted to the joint constraints of task structure, task payoff, and processing architecture. We present a model of saccadic control that separates a parametric control policy space from a parametric machine architecture, the latter based on a small set of assumptions derived from research on eye movements in reading (Engbert, Nuthmann, Richter, & Kliegl, 2005; Reichle, Warren, & McConnell, 2009). The eye-control model is embedded in a decision architecture (a (...) machine and policy space) that is capable of performing a simple linguistic task integrating information across saccades. Model predictions are derived by jointly optimizing the control of eye movements and task decisions under payoffs that quantitatively express different desired speed-accuracy trade-offs. The model yields distinct eye-movement predictions for the same task under different payoffs, including single-fixation durations, frequency effects, accuracy effects, and list position effects, and their modulation by task payoff. The predictions are compared to—and found to accord with—eye-movement data obtained from human participants performing the same task under the same payoffs, but they are found not to accord as well when the assumptions concerning payoff optimization and processing architecture are varied. These results extend work on rational analysis of oculomotor control and adaptation of reading strategy (Bicknell & Levy, ; McConkie, Rayner, & Wilson, 1973; Norris, 2009; Wotschack, 2009) by providing evidence for adaptation at low levels of saccadic control that is shaped by quantitatively varying task demands and the dynamics of processing architecture. (shrink)