The Upper Eye Bias: Rotated Faces Draw Fixations to the Upper Eye.

There is a consistent left-gaze bias when observers fixate upright faces, but it is unknown how this bias manifests in rotated faces, where the two eyes appear at different heights on the face. In two eye-tracking experiments, we measured participants' first and second fixations, while they judged the expressions of upright and rotated faces. We hypothesized that rotated faces might elicit a bias to fixate the upper eye. Our results strongly confirmed this hypothesis, with the upper eye bias completely dominating the left-gaze bias in ±45° faces in Experiment 1, and across a range of face orientations (±11.25°, ±22.5°, ±33.75°, ±45°, and ±90°) in Experiment 2. In addition, rotated faces elicited more overall eye-directed fixations than upright faces. We consider potential mechanisms of the upper eye bias in rotated faces and discuss some implications for research in social cognition.

The Roelofs and induced Roelofs effects.

The visual image provides important cues for an observer's sense of location and orientation within the world. Occasionally, though, these cues can be misleading, resulting in illusions. In the Roelofs and induced Roelofs effects, for example, a large illuminated frame, offset from the observer's midline in otherwise complete darkness, tends to bias the observer's judgment of straight ahead, causing the position of the frame, and anything contained within it, to be misperceived. Studies of these illusions have provided much insight into the processes that establish an observer's egocentric reference frame, and the manner in which object locations are encoded relative to this frame for perception and action.

An Assessment of Stereovision Acquired in Adulthood.

SIGNIFICANCE: Increasing evidence indicates that childhood binocular vision disorders that lead to stereodeficiency may be treated in adulthood. Reports of patients who gain stereopsis as adults indicate that this achievement provides for a qualitatively different and dramatically improved sense of space and depth. PURPOSE: Increasing evidence suggests that stereopsis can be achieved in adult patients despite long-standing binocular disorders. We polled individuals who gained stereopsis as adults to ascertain their initial binocular disorders, the length of time they were stereodeficient, effective treatments, and the nature of their recovered stereovision. METHODS: A questionnaire was posted online and announced in a brief article in the journal Vision Development and Rehabilitation. RESULTS: Of the 63 responders, 56 (89%) reported strabismus and/or amblyopia, and 55 (87%) indicated that they had been stereodeficient for as long as they could remember. All but seven participants (89%) achieved stereovision through vision training or a combination of surgery and vision training, and many reported vivid visual changes. CONCLUSIONS: Despite childhood binocular disorders, patients may be able to achieve stereopsis following interventions in adulthood. This achievement provides for a qualitatively different and dramatically improved sense of space and depth.

Population growth underlies most other environmental problems: Comment on Clayton et al. (2016).

The need to protect our environment is urgent, and psychology can contribute to accomplishing this goal. Combating climate change, resource exhaustion, species extinction, and other problems is an admirable goal, but such efforts will fail in the long run if the population growth that creates or exacerbates the other problems is not addressed. The large and growing human population inevitably demands more and more resources. In this comment on Clayton et al. (2016), the author proposes that psychology can identify reasons why the underlying population issue is not adequately addressed and can suggest ways to improve the situation. (PsycINFO Database Record

Consciousness around the time of saccadic eye movements.

During saccadic eye movements, the job of the nervous system is not to perceive a change in stimulation from the receptors, but to prevent a change from reaching consciousness. These movements occupy an intermediate range between actions that are almost always conscious, such as finger movements, and those that are never conscious, such as the smooth-muscle actions of the digestive system. Consciousness in this context requires attention to the consequences of an action.

Attention and memory-driven effects in action studies.

We provide empirical examples to conceptually clarify some items on Firestone & Scholl's (F&S's) checklist, and to explain perceptual effects from an attentional and memory perspective. We also note that action and embodied cognition studies seem to be most susceptible to misattributing attentional and memory effects as perceptual, and identify four characteristics unique to action studies and possibly responsible for misattributions.

Effect of Eye Height on Estimated Slopes of Hills.

Several studies have shown that slopes of hills are greatly overestimated. We have recently demonstrated that the overestimates increase logarithmically as the end point of the domain to be estimated is increased. A theoretical analysis showed that a critical parameter is the angle between the observer's line of sight and the slope of the hill, when the observer fixates the far point of the required domain. The theory predicts that increasing the observers' eye height will increase this angle, thus reducing the overestimates. Here, we test that theory by having observers stand on a box to increase their eye height. Slope estimates for various ranges again followed a logarithmic function, with lower estimates at nearer distances compared with other observers standing directly on the surface of the hill. At larger distances, slope estimates with and without increased eye height converged.

Perceived difficulty of a motor task affects memory but not action.

Successful motor interaction with a target changes memory of the target's size, which seems larger if the action was successful than if it was unsuccessful. This has been attributed to the effect of action on subsequent perception or memory. We asked what the action provides: Is feedback from the action necessary, or only the information provided by the action? We found that perceived difficulty alone changes the remembered goal characteristics, without changes in the stimuli, and before the motor task is executed. We gave observers a marble and showed them a hole in a box. They were told that throwing the marble into the hole was either difficult or easy, depending on the condition. The hole was then covered and its size judged. Participants who were told that the task was difficult judged the hole to be significantly smaller than it was, whereas those told that the task was easy made judgements not significantly different from veridical. When observers subsequently threw the marble, their success rates were independent of their own estimates of hole size or of what they had been told about the difficulty of the task, showing that their size estimates affected memory but not action. In a second experiment, we found that the effect disappeared if the hole was visible during the size estimation.

Optical correction reduces simulator sickness in a driving environment.

OBJECTIVE: We propose and test a method to reduce simulator sickness. BACKGROUND: Prolonged work in driving simulators often leads to nausea and other symptoms summarized as simulator sickness. Visual/vestibular mismatches are a frequently addressed cause; we investigate another possibility, mismatch between actual distance to a screen and depicted distances in the simulator's graphics. METHOD: Drivers negotiated a figure-8 course in a photorealistic simulator. They reported discomfort and vection every 10 minutes up to 40 min. A correction group wore optometric test frames with + 1.75 diopter lenses and prisms to converge parallel lines of sight on a screen 56 cm from the driver's eyes, preserving the normal accommodative convergence-to-accommodation (AC/A) ratio. A control group wore neutral lenses in the same test frames. In other experiments head tilt simulated vestibular experience on curves. RESULTS: The optical correction significantly reduced simulator sickness measured on a 10-point discomfort scale, where I is no problem and 10 is about to vomit. Vection ratings were similar for correction and control groups. Some drivers failed to complete the course because of high discomfort ratings, crashes, or other causes. Head tilt in the direction opposite each curve while wearing the correction did not affect discomfort, while tilt in the same direction as each curve made simulator sickness worse. CONCLUSION: Optical corrections can significantly reduce simulator sickness, though they do not eliminate it. Head tilt while driving is not recommended. Application: Simple optical corrections in spectacle frames, easily purchased at any optical facility, should be used in screen-based driving simulators. Strength of the correction depends on distance from the driver to the screen.

A slippery slope: estimated slant of hills increases with distance.

The slopes of hills tend to be greatly overestimated. Previous studies have found that slope estimates are significantly greater when estimated verbally than with a proprioceptive measure. It has yet to be determined whether these estimates are made for the entire extent of the slope, or whether the estimates in closest proximity are estimated using a different process. Since some parietal cortex neurons respond differently to objects within arm's reach, short-distance slope estimation may utilize these or analogous neurons. Alternatively, greater implied effort might make longer slopes seem steeper. We determined that both verbal and proprioceptive reports of slope are overestimates that increase logarithmically with distance from the observer, contradicting both theories. Consistent with previous work, proprioceptive estimates were more accurate at all ranges. Our results can be interpreted as a function of the angle between the observer's gaze and the plane of the hill, modified by depth cues available at only near distances.

Restoring adult stereopsis: a vision researcher's personal experience.

In February 2012, the author acquired improved stereoscopic vision after viewing Martin Scorsese's film Hugo in 3D. The author had been deficient in stereo vision all of his life because in the first two decades, one eye deviated outward from the gaze position of the other. At that time, he was an alternator (alternating exotrope) showing strabismus (>20 prism diopters) without amblyopia. After viewing the 2-hour film, the Wirt stereo threshold decreased from 200 to 80 arcsec, and stereoscopic vision became a vivid experience. Exophoria decreased to 7 prism diopters. Numerous personal and research experiences throughout the author's career helped to interpret the phenomenon, which suggests a powerful new method for treating stereo-deficient patients.

Applications of predictive control in neuroscience.

The sensory cortex has been interpreted as coding information rather than stimulus properties since Sokolov in 1960 showed increased response to an unexpected stimulus decrement. The motor cortex is also organized around expectation, coding the goal of an act rather than a set of muscle movements. Expectation drives not only immediate responses but also the very structure of the cortex, as demonstrated by development of receptive fields that mirror the structure of the visual world.

Metacontrast masking is processed before grapheme-color synesthesia.

We investigated the physiological mechanism of grapheme-color synesthesia using metacontrast masking. A metacontrast target is rendered invisible by a mask that is delayed by about 60 ms; the target and mask do not overlap in space or time. Little masking occurs, however, if the target and mask are simultaneous. This effect must be cortical, because it can be obtained dichoptically. To compare the data for synesthetes and controls, we developed a metacontrast design in which nonsynesthete controls showed weaker dichromatic masking (i.e., the target and mask were in different colors) than monochromatic masking. We accomplished this with an equiluminant target, mask, and background for each observer. If synesthetic color affected metacontrast, synesthetes should show monochromatic masking more similar to the weak dichromatic masking among controls, because synesthetes could add their synesthetic color to the monochromatic condition. The target-mask pairs used for each synesthete were graphemes that elicited strong synesthetic colors. We found stronger monochromatic than dichromatic U-shaped metacontrast for both synesthetes and controls, with optimal masking at an asynchrony of 66 ms. The difference in performance between the monochromatic and dichromatic conditions in the synesthetes indicates that synesthesia occurs at a later processing stage than does metacontrast masking.

Take the matter into your own hands: a brief review of the effect of nearby-hands on visual processing.

An exciting new line of research that investigates the impact of one's own hands on visual perception and attention has flourished in the past several years. Specifically, several studies have demonstrated that the nearness of one's hands can modulate visual perception, visual attention, and even visual memory. These studies together shed new light on how the brain prioritizes certain information to be processed first. This review first outlines the recent progress that has been made to uncover various characteristics of the nearby-hand effect, including how they may be transferred to a familiar tool. We then summarize the findings into four specific characteristics of the nearby-hand effect, and conclude with a possible neural mechanism that may account for all the findings.

Does action affect perception or memory?

Current literature maintains that success or failure in the performance of an action can modify perception of the objects of that action. The tests of that modification, however, may have measured memory rather than perception. To address this issue, the current experiment had observers throw a marble into various sized holes and assess their size through either a haptic or verbal measure. They respond either before the throw while the hole is visible (control condition), after the throw while the hole is visible (perception condition), or after the throw while the hole is not visible (memory condition). It was found that observers judged the hole size to be different depending on their throwing success only during the memory condition. This casts doubt on the conclusion of an action-specific perception account (Witt, 2011), and instead we propose an action-specific memory account.

Improved change detection with nearby hands.

Recent studies have suggested altered visual processing for objects that are near the hands. We present three experiments that test whether an observer's hands near the display facilitate change detection. While performing the task, observers placed both hands either near or away from the display. When their hands were near the display, change detection performance was more accurate and they held more items in visual short-term memory (experiment 1). Performance was equally improved for all regions across the entire display, suggesting a stronger attentional engagement over all visual stimuli regardless of their relative distances from the hands (experiment 2). Interestingly, when only one hand was placed near the display, we found no facilitation from the left hand and a weak facilitation from the right hand (experiment 3). Together, these data suggest that the right hand is the main source of facilitation, and both hands together produce a nonlinear boost in performance (superadditivity) that cannot be explained by either hand alone. In addition, the presence of the right hand biased observers to attend to the right hemifield first, resulting in a right-bias in change detection performance (experiments 2 and 3).

Embodied cognition and the perception-action link.

Perception is interpreted as a set of capabilities that facilitate two functions necessary for survival; learning about the environment and controlling real-time behavioral interactions with it. Perceptual capabilities evolve in the context of an organism and its environment, adapted to an organism's ecological niche. The relation between embodied perception and action can be studied in the context of the only muscles that serve only to enable perception--the eye muscles. The only eye movements under cognitive control are saccades, the rapid jumps of binocular fixation from one target to another. The world is perceived as stable while the retinal image, and the corresponding projections inside the brain, are displaced with each saccade. This space constancy forms the stable platform for all other visual functions and requires an explanation that involves visual short-term memory. This memory, and the change detection that it makes possible, is enhanced when there is a physical interaction between the observer and the visual stimulus. Perception is something you do, not something that happens to you.

Perception in the absence of attention: perceptual processing in the Roelofs effect during inattentional blindness.

We present two experiments that examine sensory processing during conditions of inattentional blindness. A large rectangular frame that normally induces a Roelofs effect can go unreported due to inattentional blindness. Even when participants fail to report the frame, they mislocalize an attended target in a way consistent with having processed the frame. A more demanding visuospatial distractor task can increase inattentional blindness during conditions of divided attention, but has no effect on the spatial mislocalization illusion. Our results support theories that postulate a significant amount of perceptual processing in the absence of attention.

Functions of consciousness.

Abstract Evolutionary theory indicates that consciousness has a function, if it is complex enough to be supported by genetically guided brain structures. Otherwise there would be no selective pressure against degrading it. Hints about its function come from word priming studies, where conscious awareness of a prime allows it to be avoided according to instructions. Consciousness, then, allows behavior to be driven by internal plans rather than primed contingencies from the momentary environment. Since consciousness is normally tested by memory of events, its mechanism may be a form of working memory.

Enhancing implicit change detection through action.

Implicit change detection demonstrates how the visual system can benefit from stored information that is not immediately available to conscious awareness. We investigated the role of motor action in this context. In the first two experiments, using a one-shot implicit change-detection paradigm, participants responded to unperceived changes either with an action (jabbing the screen at the guessed location of a change) or with words (verbal report), and sat either 60 cm or 300 cm (with a laser pointer) away from the display. Our observers guessed the locations of changes at a reachable distance better with an action than with a verbal judgment. At 300 cm, beyond reach, the motor advantage disappeared. In experiment 3, this advantage was also unavailable when participants sat at a reachable distance but responded with hand-held laser pointers near their bodies. We conclude that a motor system specialized for real-time visually guided behavior has access to additional visual information. Importantly, this system is not activated by merely executing an action (experiment 2) or presenting stimuli in one's near space (experiment 3). It is activated only when both conditions are fulfilled, which implies that it is the actual contact that matters to the visual system.