Oculometric investigation of internally directed cognition

Even though our eyes are open for the most of the time when awake, our attention is often directed to internal processes, thus disregarding visual stimulation from the environment. This is particularly true for cognitive tasks that are independent of external information such as creative imagination, or thinking about the future. Monitoring the focus of attention is crucial in many fields of cognitive (neuroscience) research. In the past, eye tracking has been successfully used to assess the focus of attention within the external world. So far, however, there is no objective measure of whether attention is directed to external or internal events. Different lines of research suggest that internally directed cognition (IDC) implies a state of visual disengagement and thus can be characterized by a specific oculometric response. As a first central aim, this project will hence examine the validity of oculometric parameters (OPs; i.e., eye parameters) as objective, continuous indicators of an internal vs. external focus of attention. Here we will consider well-established oculometric parameters, as well as eye vergence as a novel, straightforward measure that reflects dis-accommodation and hence is involved in visual disengagement. As another goal of the project, we will investigate interindividual differences in the capacity to enter and maintain visual disengagement, and whether these differences predict task performance in IDC tasks and are related to traits associated with cognitive control and creativity. Finally, the availability of a continuous indicator of internally directed (vs. externally directed) attention also provides new ways to study the neural correlates of IDC. This project hence is expected to represent a major advancement in research on IDC by providing insights directly relevant to our understanding of the cognitive and neural basis of attention, vision, and creativity.

Different cognitive activities imply that we direct our attention externally (e.g., reading, visual search) or externally (e.g., imagination, mental arithmetic). This research project investigated how eye behavior differs between externally and internally directed attention, and how reliably we can predict attention focus from eye behavior. Across serval studies, internal attention was indeed observed to elicit changes in various eye. Some of these changes can be attributed, in line with the perceptual decoupling hypothesis, to a reduced consideration of visual stimuli (e.g., fewer fixations); other changes can be attributed to a generally reduced visual engagement (e.g., more blinks) and higher mental load associated with the internal activity (e.g. increased pupil dilation); yet other changes may be due to an coupling of eye behavior to the internal events of ongoing imagination processes (e.g. increased variance in various eye parameters). In further studies we were able to show that these changes occur largely automatically and not due to a proactive gating of expected visual interference. In sum, we can conclude that many eye parameters are sensitive to a shift between external and internal attention focus, with several of them, however, being moderated by the specific kind of external/internal activity. Further investigations showed that the attention focus can be predicted or classified based on eye behavior. One study showed that present eye behavior predicts the likelihood of attending to a subsequent distractor. Additional studies showed that the attention focus of a person can be automatically classified, with classification accuracy depending on the amount of data and the type of external/internal activity. We also found that people are able to identify the attention focus in others through observation, even though maybe not as reliably as we might have thought. For doing so, people again mainly focus on the eye behavior of others. Another part of this project investigated the relationship between eye behavior and brain activation in the context of attention focus. An EEG study found showed that internal attention was associated with increased alpha activity in posterior brain regions, and that alpha activity further covaries with pupil dilation (an important index of internal attention) across time. An MRI study showed that internal attention was associated with increased activation in the lingual gyrus, a region associated with visual imagination; moreover, regions of the visual cortex showed a temporal covariation again exclusively with pupil dilation. Together, this project highlights that eye behavior represents a sensitive, objective indicator of whether attention is focused on external versus internal worlds. These findings could be used to assess changes in attention focus in an unobtrusive way (e.g., mind wandering or distractions in the context of driver safety or education).