Shaziela Ishak

Perceiving affordances for fitting through apertures.

Affordances--possibilities for action--are constrained by the match between actors and their environments. For motor decisions to be adaptive, affordances must be detected accurately. Three experiments examined the correspondence between motor decisions and affordances as participants reached through apertures of varying size. A psychophysical procedure was used to estimate an affordance threshold for each participant (smallest aperture they could fit their hand through on 50% of trials), and motor decisions were assessed relative to affordance thresholds. Experiment 1 showed that participants scale motor decisions to hand size, and motor decisions and affordance thresholds are reliable over two blocked protocols. Experiment 2 examined the effects of habitual practice: Motor decisions were equally accurate when reaching with the more practiced dominant hand and less practiced nondominant hand. Experiment 3 showed that participants recalibrate motor decisions to take changing body dimensions into account: Motor decisions while wearing a hand-enlarging prosthesis were similar to motor decisions without the prosthesis when data were normalized to affordance thresholds. Across experiments, errors in decisions to reach through too-small apertures were likely due to low penalty for error.

Visual Occlusion Decreases Motion Sickness in a Flight Simulator

Sensory conflict theories of motion sickness (MS) assert that symptoms may result when incoming sensory inputs (e.g., visual and vestibular) contradict each other. Logic suggests that attenuating input from one sense may reduce conflict and hence lessen MS symptoms. In the current study, it was hypothesized that attenuating visual input by blocking light entering the eye would reduce MS symptoms in a motion provocative environment. Participants sat inside an aircraft cockpit mounted onto a motion platform that simultaneously pitched, rolled, and heaved in two conditions. In the occluded condition, participants wore “blackout” goggles and closed their eyes to block light. In the control condition, participants opened their eyes and had full view of the cockpit’s interior. Participants completed separate Simulator Sickness Questionnaires before and after each condition. The posttreatment total Simulator Sickness Questionnaires and subscores for nausea, oculomotor, and disorientation in the control condition were significantly higher than those in the occluded condition. These results suggest that under some conditions attenuating visual input may delay the onset of MS or weaken the severity of symptoms. Eliminating visual input may reduce visual/nonvisual sensory conflict by weakening the influence of the visual channel, which is consistent with the sensory conflict theory of MS.

Undergraduate Psychological Writing: A Best Practices Guide and National Survey

There is no comprehensive guide for teaching psychological writing, and little is known about how often instructors teach the topic. We present a best practices guide for teaching psychological writing beyond just American Psychological Association style, discuss psychology-specific writing assignments, and examine psychological writing instruction. In an online survey, 177 psychology instructors across the United States reported on psychological writing instruction and their writing assignments. In general, we found that instructors reported using many best practices. Comparisons between courses revealed that instructors use course-specific writing instruction such that it becomes progressively complex across courses. However, instructors might not provide students with enough training to successfully complete assignments. Instructors assign diverse assignments, though, suggesting that students get varied practice at psychology-specific writing.

The Sickening Rug: A Repeating Static Pattern That Leads to Motion-Sickness-like Symptoms

The nauseogenic properties of a patterned rug that reputedly caused motion-sickness-like symptoms in those who viewed it was the topic of this study. Naive observers viewed a 1:1 scale image of the black-and-white patterned rug and a homogeneous gray region of equivalent luminance in a counterbalanced within-subjects design. After 5 min of viewing, symptoms were assessed with the simulator sickness questionnaire (SSQ), yielding a total SSQ score and sub-scores for nausea, oculomotor symptoms, and disorientation. All four scores were significantly higher in the rug condition. Observers also reported significantly more self-motion perception in the rug condition, even though they were seated during the experiment. Results are consistent with findings that suggest that neurologically normal individuals who view a repeating static pattern can experience unpleasant symptoms, some of which are similar to motion sickness.