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Morphologically marked case is in Arabic a feature exclusive to the variety of Standard Arabic, with no parallel in the spoken varieties, and it is orthographically marked only on some word classes in specific grammatical situations. In this study we test the hypothesis that readers of Arabic do not parse sentences for case and that orthographically marked case can therefore be removed with no effect on reading. Twenty-nine participants read sentences in which one of the two most frequent types of orthographically marked case was either retained or omitted, while their eye-movements were monitored. The removal of case marking from subjects in the sound masculine plural declension (changing the suffix -un [characters omitted] to -in [characters omitted]) had no negative effect on gaze duration, regressions out, or go-past time. The removal of case marking form direct objects in the triptote declension (omitting the suffix -an [characters omitted]) did however resulted in an increase in these measures. These results indicate that only some forms of case marking are required in the grammar used by readers for parsing written text.

Pupil–corneal reflection (P–CR) eye tracking has gained a prominent role in studying dog visual cognition, despite methodological challenges that often lead to lower-quality data than when recording from humans. In the current study, we investigated if and how the morphology of dogs might interfere with tracking of P–CR systems, and to what extent such interference, possibly in combination with dog-unique eye-movement characteristics, may undermine data quality and affect eye-movement classification when processed through algorithms. For this aim, we have conducted an eye-tracking experiment with dogs and humans, and investigated incidences of tracking interference, compared how they blinked, and examined how differential quality of dog and human data affected the detection and classification of eye-movement events. Our results show that the morphology of dogs' face and eye can interfere with tracking methods of the systems, and dogs blink less often but their blinks are longer. Importantly, the lower quality of dog data lead to larger differences in how two different event detection algorithms classified fixations, indicating that the results of key dependent variables are more susceptible to choice of algorithm in dog than human data. Further, two measures of the Nyström & Holmqvist (Behavior Research Methods, 42(4), 188–204, 2010) algorithm showed that dog fixations are less stable and dog data have more trials with extreme levels of noise. Our findings call for analyses better adjusted to the characteristics of dog eye-tracking data, and our recommendations help future dog eye-tracking studies acquire quality data to enable robust comparisons of visual cognition between dogs and humans. [ABSTRACT FROM AUTHOR]

Visual routines theory posits that vision is critical for guiding sequential actions in the world. Most studies on the link between vision and sequential action have considered individual agents, while substantial human behaviour is characterized by multi-party interaction. Here, the actions of each person may affect what the other can subsequently do. We investigated task execution and gaze allocation of 19 dyads completing a Duplo-model copying task together, while wearing the Pupil Invisible eye tracker. We varied whether all blocks were visible to both participants, and whether verbal communication was allowed. For models in which not all blocks were visible, participants seemed to coordinate their gaze: The distance between the participants' gaze positions was smaller and dyads looked longer at the model concurrently than for models in which all blocks were visible. This was most pronounced when verbal communication was allowed. We conclude that the way the collaborative task was executed depended both on whether visual information was available to both persons, and how communication took place. Modelling task structure and gaze allocation for human-human and human-robot collaboration thus requires more than the observable behaviour of either individual. We discuss whether an interactive visual routines theory ought to be pursued. [ABSTRACT FROM AUTHOR]

In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section "An empirically based minimal reporting guideline"). [ABSTRACT FROM AUTHOR]

Eyeblink conditioning is the most popular paradigm for studying classical conditioning in humans. But the fact that eyelids are under voluntary control means it is ultimately impossible to ascertain whether a blink response is 'conditioned' or a timed 'voluntary' blink response. In contrast, the pupillary response is an autonomic response, not under voluntary control. By conditioning the pupillary response, one might avoid potential volition-related confounds. Several attempts have been made to condition the pupillary constriction and dilation responses, with the earliest published attempts dating back to the beginning of the 20th century. While a few early studies reported successful conditioning of pupillary constriction, later studies have failed to replicate this. The apparatus for recording pupil size, the type of stimuli used and the interval between the stimuli has varied in previous attempts--which may explain the inconsistent results. Moreover, measuring the pupil size used to be cumbersome compared with today when an eyetracker can continuously measure pupil size non-invasively. Here we used an eyetracker to test whether it is possible to condition the autonomic pupillary constriction response by pairing a tone (CS) and a light (US) with a 1s CSUS interval. Unlike in previous studies, our subjects went through multiple training sessions to ensure that any potential lack of conditioning would not be due to too little training. A total of 10 participants went through 2-12 conditioning sessions, each lasting approximately 20 min. One training session consisted of 75 paired, tone + light, trials and 25 randomly interspersed CS alone trials. The eyetracker (Tobii Pro Nano), continuously measured participants' pupil size. To test statistically whether conditioning of the pupillary response occurred we compared the pupil size after the tone on the first session and the last session. The results showed a complete lack of evidence of conditioning. Though the pupil size varied slightly between participants, the size did not change as a result of the training--irrespective of the number of training sessions. The data replicate previous findings that pupillary constriction does not show conditioning. We conclude that it is not possible to condition pupillary constriction--at least not by pairing a tone and a light. One hypothesis is that when pupillary conditioning has been observed in previous studies, it has been mediated by conditioning of an emotional response. [ABSTRACT FROM AUTHOR]

The concept of optic flow, a global pattern of visual motion that is both caused by and signals self-motion, is canonically ascribed to James Gibson's 1950 book " The Perception of the Visual World. " There have, however, been several other developments of this concept, chiefly by Gwilym Grindley and Edward Calvert. Based on rarely referenced scientific literature and archival research, this article describes the development of the concept of optic flow by the aforementioned authors and several others. The article furthermore presents the available evidence for interactions between these authors, focusing on whether parts of Gibson's proposal were derived from the work of Grindley or Calvert. While Grindley's work may have made Gibson aware of the geometrical facts of optic flow, Gibson's work is not derivative of Grindley's. It is furthermore shown that Gibson only learned of Calvert's work in 1956, almost a decade after Gibson first published his proposal. In conclusion, the development of the concept of optic flow presents an intriguing example of convergent thought in the progress of science. [ABSTRACT FROM AUTHOR]