Geometrical illusions in solid objects under ordinary viewing conditions.

The Müller-Lyer and Ponzo illusions were obtained under free binocular viewing of three-dimensional objects, and the function relating magnitude of illusion to fin angle, characteristic of converging-line versions of the Müller-Lyer pattern, was closely paralleled by volumetric (three-cone), line-free objects (but not with an erect, planar "walk-through" construction and moving observers). Illusions cannot be dismissed as artifacts of static, impoverished viewing, therefore, but must be explained within any general theory of perception. Perspective explanations have difficulties with such three-dimensional manifestations, and seem completely inapplicable to our further finding that approximately the same amount of illusion occurred in objects and patterns with no oblique lines or edges. Confusion or averaging theories, not themselves tested here, remain unthreatened by these data.     

Geometrical illusions in solid objects under ordinary viewing conditions

The Müller-Lyer and Ponzo illusions were obtained under free binocular viewing of three-dimensional objects, and the function relating magnitude of illusion to fin angle, characteristic of converging-line versions of the Müller-Lyer pattern, was closely paralleled by volumetric (three-cone), line-free objects (but not with an erect, planar “walk-through” construction and moving observers). Illusions cannot be dismissed as artifacts of static, impoverished viewing, therefore, but must be explained within any general theory of perception. Perspective explanations have difficulties with such three-dimensional manifestations, and seem completely inapplicable to our further finding that approximately the same amount of illusion occurred in objects and patterns with no oblique lines or edges. Confusion or averaging theories, not themselves tested here, remain unthreatened by these data.     

Haitian and Haitian American experiences of racism and socioethnic discrimination in Miami-Dade county: At-risk and court-involved youth

We examine how juvenile justice-involved youth of Haitian descent in Miami-Dade County cope with structural racism and its impact on their mental health. Drawing on longitudinal ethnography, psychosocial assessment data, and a family-based clinical intervention funded by the National Institute on Drug Abuse, this article explores youth narratives of discrimination prior to and during the COVID-19 pandemic. We use critical race theory and theory of practice to understand youths’ perceptions as racialized bodies and stigmatized selves, highlighting the experiences and perspectives of a particular black immigrant group, ethnic beings caught up in the everyday practices of racialization, sociocultural marginalization, and racism. We frame these experiences as a variation of the complex continuum of structural racism and racial domination in the US. These experiences have caused anger, fear, anxiety, chronic anticipatory distress, and hopelessness among youth of Haitian descent. We conclude with some recommendations for therapeutic support that encourages youth to process their experiences, promotes their development of a positive self-concept, and provides them with mind-body techniques to attenuate the physical impacts of discriminatory events. The clinical trial registration number for this study intervention is NCT03876171.     

Required pecking alters judgments of the passage of time by pigeons

There is evidence that how humans perceive time is affected by the activity in which they are engaged when they are judging time. In humans, typically, the more demanding the task, the faster time seems to pass. We asked whether a similar effect could be found in pigeons. Pigeons were trained to discriminate between a short-(2-sec) and a long-(10-sec) duration stimulus. Depending on the color of the stimulus (white or blue), the pigeons were required to peck (at least once per second or the trial was aborted) or to refrain from pecking (pecks aborted the trial). Once these tasks had been acquired to a high degree, probe trials involving white and blue stimuli were presented at durations between 2 and 10 sec. On trials in which the pigeons were required to peck, the point of subjective equality (i.e., the point at which pigeons are equally likely to choose the stimulus associated with long stimuli as the stimulus associated with short stimuli) was almost 1 sec longer than on trials in which the pigeons were required to refrain from pecking. In other words, on trials that required pecking, more time passed before the pigeons indicated that the probe duration was at the subjective midpoint between 2 and 10 sec than on trials that did not require pecking. This result suggests that like humans, the pigeons underestimated the passage of time when they were active or when attention to time-related cues had to be shared with attention to satisfying the response rate requirement.     

Second-order contrast based on the expectation of effort and reinforcement

Pigeons prefer signals for reinforcement that require greater effort (or time) to obtain over those that require less effort to obtain (T. S. Clement, J. Feltus, D. H. Kaiser, & T. R. Zentall, 2000). Preference was attributed to contrast (or to the relatively greater improvement in conditions) produced by the appearance of the signal when it was preceded by greater effort. In Experiment 1, the authors of the present study demonstrated that the expectation of greater effort was sufficient to produce such a preference (a second-order contrast effect). In Experiments 2 and 3, low versus high probability of reinforcement was substituted for high versus low effort, respectively, with similar results. In Experiment 3, the authors found that the stimulus preference could be attributed to positive contrast (when the discriminative stimuli represented an improvement in the probability of reinforcement) and perhaps also negative contrast (when the discriminative stimuli represented reduction in the probability of reinforcement).     

Information integration in judgements of time to contact

Time to contact (TTC) is specified optically by tau, and studies suggest that observers are sensitive to this information. However, TTC judgements also are influenced by other sources of information, including pictorial depth cues. Therefore, it is useful to identify these sources of information and to determine whether and how their effects combine when multiple sources are available. We evaluated the effect of five depth cues on TTC judgements. Results indicate that relative size, height in field, occlusion, and motion parallax influence TTC judgements. When multiple cues are available, an integration (rather than selection) strategy is used. Finally, the combined effects of multiple cues are not always consistent with a strict additive model and may be task dependent.