Illusions of brightness, length, and now size: comparable effects derived from the Craik-O'Brien-Cornsweet distributions

Analogous illusions of brightness, line length, and object size occur when stimulus distributions follow the Mach function. Similarly, analogous illusions of brightness and length are produced by stimulus distributions that follow the Craik-O'Brien-Cornsweet function. In Exp. 1, object size is studied using Craik-O'Brien-Cornsweet stimuli composed of 12 clip-art representations of candles, swords, forks, screwdrivers, or pens. Despite their equal dimensions, the three objects next to the taller gradient were judged larger than the three adjacent to the shorter gradient. In Exp. 2, variations of the sword and screwdriver figures having three separations of their constituent objects were used. The illusion produced in Exp. 1 was replicated and, for the figures composed of screwdrivers, increasing separation reduced the hypothesized mis-estimations. The relationship of these Craik-O'Brien-Cornsweet size illusions to their brightness and length counterparts mirrors the relationships previously reported for Mach stimuli; moreover, these findings converge to suggest that the visual system registers size of objects with a frequency code and that illusions of size appear when interactions among neurons disrupt this code.     

Effectiveness of Combining Worked Examples and Deliberate Practice for High School Geometry

Sixty‐nine high school students practised on geometry subtopics using worked example–problem pairs. The free‐choice group had a choice of their practice pairs, whereas the deliberate practice group was presented with practice tasks that covered all and only their weak areas as determined by a pretest. The results demonstrated a significant instructional group by level of expertise interaction with superior performance by the deliberate practice group over the free‐choice group for more knowledgeable learners playing the major role in the significant interaction. On the basis of these findings, optimal strategies for organizing student practice in secondary classrooms are discussed in terms of cognitive load factors and expert–novice differences. It was concluded that a deliberate practice strategy over a free‐choice strategy was desirable for more knowledgeable but not for less knowledgeable learners. Copyright © 2014 John Wiley & Sons, Ltd.     

Using segmentation to support the learning from animated soccer scenes: An effect of prior knowledge

ObjectivesWe used a cognitive load perspective to investigate the effects of levels of learner expertise and different forms of segmentation in learning from animated soccer scenes.MethodExpert and novice players (N = 48) completed a recall reconstruction-test and rated their invested mental effort after studying a continuous animation, a macro-step and a micro-step segmented animation.ResultsFindings demonstrated an expertise reversal effect for segmentation. It positively affected learning outcomes of novices but not experts (even though they still invested less mental effort and repeated the animation less often in the two segmented conditions). Additionally, novices benefited more from micro-step segmentation than from macro-step segmentation, while experts performed at the same level with both forms of segmentation.ConclusionsStudy results suggested that adapting instructional animation formats to players with different levels of expertise should be a crucial part of successful training.     

Managing split‐attention and redundancy in multimedia instruction

Two experiments investigated alternatives to split‐attention instructional designs. It was assumed that because a learner has a limited working memory capacity, any increase in cognitive resources required to process split‐attention materials decreases resources available for learning. Using computer‐based instructional material consisting of diagrams and text, Experiment 1 attempted to ameliorate split‐attention effects by increasing effective working memory size by presenting the text in auditory form. Auditory presentation of text proved superior to visual‐only presentation but not when the text was presented in both auditory and visual forms. In that case, the visual form was redundant and imposed a cognitive load that interfered with learning. Experiment 2 ameliorated split‐attention effects by using colour coding to reduce cognitive load inducing search for diagrammatic referents in the text. Mental load rating scales provided evidence in both experiments that alternatives to split‐attention instructional designs were effective due to reductions in cognitive load. Copyright © 1999 John Wiley & Sons, Ltd.     

What variables control (long-range) apparent motion?

A solid (ie filled-in) two-dimensional form is seen in motion toward another solid object of different shape and not towards an outline object of the same shape. The interpretation of these findings in terms of luminance-domain spatial frequency filtering is challenged by experiments in which the same results were obtained with kinetic and cyclopean forms.