Loy Anderson

Demonstration experiments in perception and cognitive psychology for the Macintosh computer

A package of programs demonstrating psychology experiments widely cited in perception and cognitive psychology textbooks is described. The programs are suitable for laboratory research projects and in-class demonstrations. An attractive feature of the programs is that they have provisions for changing experimental parameters to allow students to design different experiments from the original programs. Iconic memory, memory scanning (using the additive factors approach), lexical decision, target detection, speeded classification, picture recognition/picture memory, and the Phi phenomenon can be demonstrated.

Comparing Three-Dimensional Representations of Data to Scatterplots

Jensen (1985) described a method for presenting data in a three-dimensional format that would typically be presented in a scatterplot. The present paper compared these two methods of presenting data. Twenty-four subjects, all of whom had completed an undergraduate class in statistics, were presented with sets of graphs depicting bi-variaté data that varied in correlation from about 0.0 to about .99. Three different data groups were depicted as both scatterplots and as three-dimensional graphs. Subjects rank ordered these sets of graphs on the basis of the degree of relationship present. For each set of graphs the order the subject chose was compared with the known order using Spearmans rho. In the early trials performance was better with the scatterplots, but by the last trial there was no difference between presentation methods for two out of the three data groups presented. The implications and limitations of these data are discussed.

Determining Perceived Traffic Sign Dimensions with Multidimensional Scaling

The evaluation of current and potential traffic signs is necessary in order to ensure that the signs are effective. Laboratory studies are an important first step in evaluating current and potential traffic signs in order to minimize the risk and expense associated with field research. This paper describes the application of multidimensional scaling to traffic signs, a method that appears to be well suited for determining perceived traffic sign dimensions. In two studies subjects judged the similarity of all possible pairs of 16 traffic signs. Three interpretable dimensions were found. These dimensions, in order of extraction, were color/content, message form (pictorial vs. verbal), and shape. The validity of this research technique and the limitations of these research results are discussed.

Attention and Visual Perception: The Availability of Features

Results from two experiments employing a location-cueing paradigm demonstrated that the features of a visual stimulus do not appear to be used for stimulus identification at a time prior to the localization of the stimulus by an attentional system. However, the experiments also revealed that a stimulus is processed (at least to some extent) prior to the arrival of attention at the stimulus. The results support the hypothesis that a visual stimulus must be located by an attentional system before results of initial processing of the stimulus can be used in identification. Implications for the design of visual display systems in which it is important for the user to identify stimuli both quickly and accurately are discussed.

Does Location Cueing Increase the Efficiency of the Early Stages of Perceptual Processing

Previous research has shown that precueing a stimuluss location in an otherwise empty field leads to more efficient detection of that stimulus. The experiments reported here sought to determine whether or not such cueing affects the early stages(s) of perception. If cueing affects early perceptual processing, then the effect of cueing should be larger the more difficult the perceptual task; otherwise it should not. Experiment 1 failed to find any facilitation due to cueing, but did find significant inhibition from invalid cues. The size of the inhibition did not differ significantly as a function of perceptual difficulty. Experiment 2 employed a less attention-demanding type of cueing and found significant facilitation as well as inhibition. As in the first experiment, the size of the cueing effect did not differ significantly as a function of difficulty. Experiment 3 used a stronger manipulation of difficulty and obtained essentially the same results. However, there was some tendency for the effect of cueing to be larger in the more difficult condition. Experiment 4 tested the possibility that this tendency occurred because the perceptual task was so difficult it required voluntary eye movements. When the possible role of eye movements was minimized, there was no tendency for the effect of cueing to be larger in the difficult than in the easy condition. In Experiment 5 the possibility of eye movements was reduced even further and again, found no significant interaction between cueing and difficulty. It was concluded that cueing does not facilitate early perceptual processing. Rather, cueing affects the efficiency with which stimuli are selected for further processing from an unlimited capacity perceptual system to a limited capacity system.