Heading and path information from retinal flow in naturalistic environments

In four experiments, we explored the heading and path information available to observers as we simulated their locomotion through a cluttered environment while they fixated an object off to the side. Previously, we presented a theory about the information available and used in such situations. For such a theory to be valid, one must be sure of eye position, but we had been unable to monitor gaze systematically; in Experiment 1, we monitored eye position and found performance best when observers fixated the designated object at the center of the display. In Experiment 2, when we masked portions of the display, we found that performance generally matched the amount of display visible when scaled to retinal sensitivity. In Experiments 3 and 4, we then explored the metric of information about heading (nominal vs. absolute) available and found good nominal information but increasingly poor and biased absolute information as observers looked farther from the aimpoint. Part of the cause for this appears to be that some observers perceive that they have traversed a curved path even when taking a linear one. In all cases, we compared our results with those in the literature.     

An electronic visual stimulator

A group of circuits is described that produce various patterns on an oscilloscope screen that are useful in studying vision. These patterns are: a flashing bar, a drifting bar, a flashing grating, and a drifting grating. The circuits have controls for: contrast, velocity, width, position, and orientation with respect to the vertical. This article describes the principles of design and use of these circuit modules as a precise electronic visual stimulator.     

Distance estimation in a dynamic simulated environment: a visual field dependence problem?

Egocentric distance estimation implies that the subject perceives his own location in the environment. In a simulated environment, subjects have to transpose perceptively their own observation point in order to assume their virtual body position. As only visual information specifies this position, their ability to perceive the camera viewpoint should be linked to the field dependence independence factor (FDI). Field-independent subjects underestimated the mid-distance between their own virtual body position and a far-located target; their bisection was located between the projective (2-D) and the simulated (3-D) mid-distance which indicates their difficulty in considering the in-depth simulated spatial references. High correlations between the vertical estimation in the rod-and-frame test and the egocentric-distance-estimation task (with shifted camera) suggest a similar perceptive process in both tasks. This result is confirmed by the better performances of the field-dependent subjects in this condition. In conclusion, we discuss the relationship between FDI and the sense of presence in virtual environments.     

Introduction: A Cognitive Science Slam in Honor of Guy Van Orden

Illusory depth perception experienced in driving simulators is afforded by monocular depth information contained in visual displays. Presumably binocular convergence and binocular disparity, though useful for depth perception in real environments, may poorly contribute to illusory depth in a driving simulator. Instead, they may generate conflicting information by revealing the distance of the display screen and its flatness. Nevertheless, illusory depth induced by monocular information contained in visual displays usually produces enough immersion and realism to create the illusion of driving in a real environment.

Many authors have noted improved depth perception in paintings, photographs, and even in drawings when viewed monocularly. However, this effect, known as monocular advantage, has never been explored in driving simulation. The purpose of this experiment was to assess whether the effect might exist in driving simulation. It was expected that drivers would perceive distances in depth better and more accurately with a monocular than with a binocular viewing of the display. Distance estimates were evaluated for two types of driving maneuvers referred to as alignment and bisection. Results showed that when significant performance differences between monocular and binocular viewing conditions occurred, target cars were perceived farther in depth and more accurately using monocular vision.

Alternative viewing conditions using both eyes are discussed at the end of the article.     

Gender differences in implicit and explicit personality traits

This article investigates gender differences in implicit and explicit measures of the Big Five traits of personality. In a high-powered study (N = 14,348), we replicated previous research showing that women report higher levels of Agreeableness, Conscientiousness, Extraversion and Neuroticism. For implicit measures, gender differences were much smaller for all, and opposite in sign for Extraversion. Somewhat higher levels of implicit Neuroticism and Agreeableness were observed in women, and somewhat higher levels of implicit Extraversion and Openness were observed in men. There was no gender difference in implicit Conscientiousness. A possible explanation is that explicit self-concepts partly reflect social norms and self-expectations about gender roles, while implicit self-concepts may mostly reflect self-related experiences.     

Positive associations primacy in the IAT: a many-facet rasch measurement analysis

Two studies investigated the different contribution of positive and negative associations to the size of the Implicit Association Test (IAT) effect. A Many-Facet Rasch Measurement analysis was applied for the purpose. Across different IATs (Race and Weight) and different groups of respondents (White, Normal weight, and Obese people) we observed that positive words increase the IAT effect whereas negative words tend to decrease it. Results suggest that the IAT is influenced by a positive associations primacy effect. As a consequence, we argue that researchers should be careful when interpreting IAT effects as a measure of implicit prejudice.     

The development of distance estimation in optic flow

In three experiments we tested the ability of children aged 8 to 12 years and adults to locate a target in an optic texture flow projected onto the ground. During the exposure phase, a static target (diode) was lit up at 6 m or 8 m on the ground in front of the subject. During the pointing phase, the subject was asked to indicate the perceived location of the target with a laser pointer as soon as the target was switched off. In the first experiment, during both phases the optic texture (environment) was either motionless or approaching the subject. Results showed that target locations were significantly more underestimated within the moving texture than within the still texture. In the second experiment, a detailed error analysis showed that the differences of performance between children and adults were not due to differences in eye height. Errors can be described by a linear fit with the retinal speed of the optic flow surrounding the targets. Distance judgments improved from the age of 8 years onwards. In the last experiment we found the same kind of results with a receding texture and without stimulation in central vision. Results are discussed in terms of subject's capacity to compensate for the effect of linear vection produced by the optic flow.     

A discrimination–association model for decomposing component processes of the Implicit Association Test

A formal model is proposed that decomposes the Implicit Association Test (IAT) effect into three process components: stimuli discrimination, automatic association, and termination criterion. Both response accuracy and reaction time are considered. Four independent and parallel Poisson processes, one for each of the four label categories of the IAT, are assumed. The model parameters are the rate at which information accrues on the counter of each process and the amount of information that is needed before a response is given. The aim of this study is to present the model and an illustrative application in which the process components of a Coca–Pepsi IAT are decomposed.     

A system for controlling the light output of a monochromator by any simple function and for temporally modulating the intensity

This paper describes an apparatus that controls the output of a monochromator so that the energies in each waveband can be equated according to any desired function. A photocell monitors the light from the monochromator and provides a feedback to the power supply driving the lamp. A function generatoris mechanically linked to the monochromator’s wavelength drive and provides the function for correcting the output spectrum. Once set, the light output remains constant even if the bulb ages or is replaced. If desired, a sinusoidalripple of variable frequency and amplitude can be imposed on the mean intensity of the light.     

Assessing the impact of replication on implicit association test effect by means of the extended logistic model for the assessment of change

The present study consists of a longitudinal investigation in which implicit association measures were collected by means of the implicit association test (IAT), with the purpose of assessing the impact of replication on the test effect with the same participants. The extended logistic model for the assessment of change (ELMAC), a procedure that belongs to Rasch modeling, was applied. By means of the ELMAC application, the existence of latent traits characteristic of the impact on the IAT effect (due to replication through time) is shown; more precisely, the model time parameters show the decrement of the IAT effect through time, due to the decrease of the implicit preference in both conditions, compatible and incompatible, associated with sweet foods and salty foods. The results confirm that in the long run, the incompatible condition latency may approach the compatible condition latency, causing a significant attenuation of the IAT effect.