John H. Flowers

Cross-Modal Equivalence of Visual and Auditory Scatterplots for Exploring Bivariate Data Samples:

The equivalence of visual and auditory scatterplots was examined in two experiments. Experiment 1 examined the relationship between actual Pearsons r and visual and auditory judgments of direction and magnitude of correlation for 24 bivariate data samples. Experiment 2 directly evaluated visual and auditory perceptual sensitivity to outliers by examining changes in perceived magnitude and direction of correlation estimates for scatterplots from Experiment 1 that were altered by the addition of outlier points. Results suggest that the information conveyed by visual and auditory scatterplots is used very similarly by the two modalities. Both visual and auditory scatterplots are quite efficient in conveying sign and magnitude of correlation, and the effect of outliers on judged magnitude of correlation is similar for the two types of data display.

The effect of flanking context on visual classification: The joint contribution of interactions at different processing levels

Flanking characters that surround a target character may cause either facilitation of or interference with target classification, depending on experimental context. In three different experiments, the patterns of facilitative priming and interference were shown to change systematically as a function of onset asynchrony between flankers and target, illustrating differing time courses of the overlapping processes that each contributes to overall reaction time performance.

An investigation of the cognitive and perceptual dynamics of a colour-digit synaesthete

L, a 47-year-old female of Choctaw descent, was first identified as a potential synaesthete on the basis of self-report data regarding digit-colour associations. Upon completion of the identification procedures typified in the literature, it was concluded that L met the classic memory-performance criteria used to identify synaesthetic ability. A series of Stroop-type tasks were then performed to identify the dynamics of her synaesthetic experiences. The results of these analyses provided three findings of note. First, the clear pattern of response-time differences between L and the control group suggests that tasks designed to produce involuntary divisions of attention can be an effective means by which to demonstrate that synaesthetic experiences are involuntary but elicited. Second, the significantly slower performance by L on a negative-priming Stroop list shaped around her colour – digit associations indicates the presence of a lexical component in her synaesthetic experience. Third, the use of a manual colour-classification task for which a verbal response was not employed served to confirm the presence of a lexical component in Ls synaesthetic experiences. The implications of these results for current synaesthetic theories are then discussed. Finally, a clustering solution of a portion of Ls colour–digit experiences is presented, along with the ramifications of its results on the nature of Ls perceptual experience.

Musical versus Visual Graphs: Cross-Modal Equivalence in Perception of Time Series Data

By applying multidimensional scaling procedures and other quantitative analyses to perceptual dissimilarity judgments, we compared the perceptual structure of visual line graphs depicting simulated time series data with that of auditory displays (musical graphs) presenting the same data. Highly similar and meaningful perceptual structures were demonstrated for both auditory and visual modalities, showing that important data characteristics (function slope, shape, and level) were perceptually salient in either presentation mode. Auditory graphics may be a highly useful alternative to traditional visual graphics for a variety of data presentation applications.

Priming effects in perceptual classification

Priming stimuli that spatially flank a fixated target stimulus may cause either facilitation or interference with target classification, depending on experimental context. Two experiments demonstrated distinct effects of response compatibility and semantic congruity between flankers and target. Response competition occurred when targets were flanked by context stimuli associated with the opposite response, but this effect diminished when the target was delayed relative to the flankers. Facilitative priming by response-compatible flankers, in contrast, required prior exposure of the flankers, and was strongly influenced by the semantic congruity of flankers and targets. These differing time courses suggest that perceptual priming encompasses a variety of distinct underlying cognitive and motor events.

Response and encoding factors in “ignoring” irrelevant information

Subjects classified either the numerosity or numeric value of elements in successive stimulus displays. In separate experiments, responses were indicated by oral naming, card sorting, manual tapping, and oral “tapping.” Incongruent levels of numeric value slowed naming and sorting, but not tapping, when numerosity was the cue for responding. Incongruent numerosity slowed tapping, but not naming and sorting, when numeric value was the cue. Changes in stimulus response mapping may thus critically alter the ability to ignore an irrelevant stimulus dimension.

Data sonification from the desktop: Should sound be part of standard data analysis software?

The design of auditory formats for data display is presently focused on applications for blind or visually impaired users, specialized displays for use when visual attention must be devoted to other tasks, and some innovative work in revealing properties of complex data that may not be effectively rendered by traditional visual means. With the availability of high-quality and flexible sound production hardware in standard desktop computers, the potential exists for using sound to represent characteristics of typical “small and simpl” samples of data in routine data inspection and analysis. Our research has shown that basic properties of simple functions, distribution properties of data samples, and patterns of covariation between two variables can be effectively displayed by simple auditory graphs involving patterns of pitch variation over time. While such developments have implications for specialized applications and populations of users, these displays are easily comprehended by normal users with minimal practice. Providing further software enhancement to encourage exploration of data representation by sound may lead to a variety of useful creative developments in data display technology.

Creativity and Perception

Informal thought about the nature of mental operations important to creative human behavior suggests that perceptual processes are of considerable importance. The ability to “see relationships among elements” is an attribution commonly made toward authors of major scientific discoveries or of noteworthy artistic achievements. For example, Shepard (1978, 1981) documented self-reports from several creative scientists and authors that strongly emphasize the role of visual imagery and the manipulation of visual codes in the creative process.

Selective attention between words, shapes and colors in speeded classification and vocalization tasks

The presence of irrelevant words (incongruent color and shape names) substantially slowed the sorting of shapes and colors. This interference was maintained over four sessions of practice for color sorting, but essentially vanished for shape classification and color classification using stimuli in which the word and color were physically separated. Interference with oral naming was maintained over 4 days of practice for all types of stimuli, demonstrating that spatial selectivity of attention is highly dependent upon the response requirements of the task.

How does familiarity affect visual search for letter strings

Subjects visually searched for letter string targets consisting of either familiar English three-letter words (e.g., SEX) or featurally similar nonword trigrams (e.g., SFX). Distractor items were either words or nonwords and had varying degrees offeature overlap with the target among different blocks of trials. Search was facilitated by a word-nonword category distinction between target and distractors, particularly when target-noise feature overlap was high, but such facilitation consisted of slope reductions in an apparently serial, self-terminating search pattern as opposed to a “pop-out” effect.