Processes underlying dimensional interactions: Correspondences between linguistic and nonlinguistic dimensions

In six experiments, we examined speeded classification when one dimension was linguistic and the other was nonlinguistic. In five of these, attributes on the dimensions corresponded meaningfully, having in common the concepts "high" and "low." For example, in Experiment 1, the visually presented words HI and LO were paired with high- or low-pitched tones; in Experiment 2, the dimensions were visual words and vertical position, in Experiment 3, they were spoken words and position, and in Experiments 4 and 5, spoken words and pitch. For each dimension in each pair, subjects suffered Garner interference when dimensions were varied orthogonally. Garner interference remained constant across 15 blocks of trials (Experiment 5). Subjects also showed significant congruity effects in all experiments, with attributes from congruent stimuli (e.g., HI/high pitch) classified faster than attributes from incongruent stimuli (e.g., HI/low pitch). These results differ from those obtained previously with noncorresponding pairs of linguistic-nonlinguistic dimensions. The results also differ from those obtained with traditional Stroop dimensions (colors and color words; Experiment 6), which showed minimal Garner interference and diminishing congruity effects across blocks of trials. We conclude that the interactions found here represent cross-talk between channels within a semantic level of processing. We contrast our view with current models of dimensional interaction.     

Selective attention to Stroop dimensions: Effects of baseline discriminability,response mode,and practice

The framework of dimensional interaction was used to test the hypothesis that the Stroop effect is partially rooted in mismatches in baseline discriminability, with stimulus differences along the word dimension typically exceeding stimulus differences along the color dimension. Subjects made speeded classifications, with either keypresses or vocalizations, of either words or colors. Stroop congruity and Garner interference were measured under conditions in which discriminabilities were (1) matched (Experiments1 and 4), (2) mismatched in favor of colors (Experiment 2), or (3) mismatched in favor of words (Experiment3). When matched, colors and words appeared separable, with small interactive effects being reduced or eliminated through practice. When mismatched, asymmetric Stroop and Garner effects emerged, with the more discriminable dimension disrupting classification of the less discriminable dimension. Asymmetric effects were obtained in both response modes, and were not alleviated by practice. We conclude that (1) the Stroop effect is an optional effect, and (2) unequal discriminability causes a mandatory failure of selective attention.     

Visual-auditory interaction in speeded classification: Role of stimulus difference

An experiment examined cross-modal interference and congruence in speeded classification: Subjects had to identify compound (visual-auditory) stimuli as either low or high in spatial position (visual judgment) or low or high in pitch (auditory judgment), in 16 conditions, each of which combined one of four possible pairs of tones, varying in frequency difference, with one of four possible pairs of dots, varying in positional difference. Both classification by position and classification by pitch revealed Garner interference (poorer performance than baseline, with orthogonal variation in the irrelevant dimension) and congruence effects (better performance with congruent than with incongruent stimulus combinations), but pitch classification showed more. Furthermore, the size of the pitch difference strongly affected classification by pitch and less strongly affected classification by position, but the size of the position difference affected neither. The findings are consistent with the view that Garner interference and congruence effects are closely related, perhaps arising from a common source, and suggest that the asymmetries could depend in part on the degree of dimensional overlap between stimuli and responses.     

Dimensional interaction between color and pitch

In three experiments I investigated the nature of cross-modal dimensional interaction by testing speeded classification of the synesthetically corresponding dimensions of color (white-black) and pitch (high-low). Experiment 1 showed significant Garner interference when these dimensions were varied orthogonally--redundancy gain for positively correlated dimensions and redundancy loss for negatively correlated dimensions. Attributes from synesthetically congruent stimuli were classified faster than attributes from incongruent stimuli (a congruity effect). Experiment 2 tested a perceptual explanation of this interaction (i.e., that color and pitch are configural dimensions) by using Pomerantz's (1986) diagnostic (comparison of selective and divided attention performance). The configurality hypothesis received little support. Experiment 3 examined the effect of optional processes on color and pitch classification. The results suggest that partly strategic and partly mandatory components may constitute overall performance. Three alternative explanations of the color-pitch interaction--perceptual, semantic, and response based--are evaluated in the context of the present results.     

Interaction among auditory dimensions: timbre, pitch, and loudness

In two experiments, we examined whether or not pairs of auditory dimensions--timbre-loudness (Experiment 1) and timbre-pitch (Experiment 2)--interact in speeded classification. Subjects classified values from one dimension while the other dimension was (1) held constant (baseline), (2) varied orthogonally (filtering), or (3) correlated linearly. The subjects showed substantial Garner interference when classifying all dimensions--that is, poor performance at filtering relative to baseline. Timbre and loudness displayed redundancy gain (i.e., performance faster than baseline) when correlated positively, but redundancy loss (i.e., interference) when correlated negatively. Timbre and pitch displayed redundancy gain however dimensions were correlated. Both pairs of dimensions showed substantial effects of congruity: Attributes from one dimension were classified faster when paired with "congruent" attributes from the other dimension. The results are interpreted in terms of an interactive multichannel model of auditory processing.     

Perceptual and linguistic interactions in speeded classification: tests of the semantic coding hypothesis

We tested the semantic coding hypothesis, which states that cross-modal interactions observed in speeded classification tasks arise after perceptual information is recoded into an abstract format common to perceptual and linguistic systems. Using a speeded classification task, we first confirmed the presence of congruence interactions between auditory pitch and visual lightness and observed Garner-type interference with nonlinguistic (perceptual) stimuli (low-frequency and high-frequency tones, black and white squares). Subsequently, we found that modifying the visual stimuli by (a) making them lexical (related words) or (b) reducing their compactness or figural 'goodness' altered congruence effects and Garner interference. The results are consistent with the semantic coding hypothesis, but only in part, and suggest the need for additional assumptions regarding the role of perceptual organization in cross-modal dimensional interactions.     

Garner and congruence effects in the speeded classification of bimodal signals

The role of attention in speeded Garner classification of concurrently presented auditory and visual signals was examined in 4 experiments. Within-trial interference (i.e., congruence effects) occurred regardless of the attentional demands of the task. Between-trials interference (i.e., Garner interference) occurred only under conditions of divided attention when making judgments about auditory signals. Of importance, the data show congruence effects in the absence of Garner interference. Such a pattern has been rarely reported in studies of the classification of purely visual stimuli and contradicts theoretical accounts asserting that the effects share a common locus. The data question the notion that Garner classification reveals fundamental insights about the nature of the perceptual processing of bimodal stimuli.     

Cross-sensory correspondences and cross talk between dimensions of connotative meaning: Visual angularity is hard, high-pitched, and bright

Higher-pitched sounds are judged to be, among other things, sharper, harder, and brighter than lower-pitched sounds. Following Karwoski, Odbert, and Osgood (Journal of General Psychology 26:199-222, 1942), such cross-sensory correspondences are proposed to have a semantic basis, reflecting extensive bidirectional cross-activation among dimensions of connotative meaning. On this basis, the same core set of correspondences should emerge whichever sensory feature is used to probe it. More angular (sharper) shapes should, for example, be higher-pitched and have the same cross-sensory features as higher-pitched sounds. Experiments 1–3 employed a speeded classification task designed to reveal cross-sensory correspondences having a semantic basis. With words as to-be-classified stimuli and with shapes varying in angularity as concurrent incidental stimuli, congruity effects between angularity and each of hardness, pitch, and brightness were confirmed. Correspondences with a semantic basis need not be cross-modality in nature. Experiment 4 confirmed this by reproducing the brightness–angularity congruity effect when contrasting values for both features were encoded nonverbally within the visual modality. The varying nature and origins of cross-sensory correspondences and the basis on which they induce congruity effects in speeded classification are explored.     

Dimensional interactions in vibrotactile information processing

The effect of irrelevant dimensional variation on the processing of vibrotactile stimuli was measured. Six observers performed a speeded classification task with stimuli varying along the dimensions of pitch and loudness. Choice reaction times were obtained for stimuli differing on one dimension alone, on two correlated dimensions, or on two orthogonally varied dimensions. Compared to one-dimension performance, reaction times were faster in the correlated condition and slower in the orthogonal condition. In general, these findings agreed with similar experiments in other modalities, with the exception that the effects in this study tended to be stronger for cases in which loudness, rather than pitch, was the relevant dimension. The results are explained in terms of the integrality of pitch and loudness and of the relative discriminability of dimensions.     

Processing linguistic and perceptual dimensions of speech: interactions in speeded classification.

Performance on selective-attention and divided-attention tasks shows strong and consistent interactions when participants rapidly classify auditory stimuli whose linguistic and perceptual dimensions (the words low vs. high, low and high pitch, low and high position in space) share common labels. Compared with baseline performance, response times were greater when one or two irrelevant dimensions varied (Garner interference) and when combinations of attributes were incongruent rather than congruent (congruence effects). Performance depended only on the congruence relationships between the relevant dimension and each of the irrelevant dimensions and not on the congruence relationships between the irrelevant dimensions themselves. In selective attention, an additive multidimensional model accounts well for the patterns of both Garner interference and congruence effects.     

Some perceptual dependencies in speeded classification of vowel color and pitch

Wood (1975) suggested that information specifying consonant identity is dependent on the earlier processing of pitch. Is vowel identification also dependent on the prior processing of pitch? In contrast with the results obtained with consonants, Kuhl (1975, 1976) reported that infants responded selectively to differences in vowel color when pitch varied but not to differences in pitch when vowel color varied. Miller (1978) has also reported that adults show mutual, symmetric interference effects in speeded classification of vowel color and pitch, In the present study, judgments of vowel color and pitch were examined in a reaction time task in order to assess the effects of the relative discriminability of vowel and pitch quality on speeded classification. In addition, we also compared the classification of isolated vowels to vowels in consonantal context. The overall results were consistent with both Kuhl’s and Miller’s earlier findings but refine our understanding of the interaction between various dimensions by showing that vowel identification is also dependent on the processing of pitch information. Such an interaction, however, becomes evident only when the processing dependencies are examined across a wide range of stimulus values for each dimension. The present findings provide additional information about the nature of processing dependencies among dimensions in speech and the methods by which such dependencies may be studied.     

Sequence-sensitive exemplar and decision-bound accounts of speeded-classification performance in a modified Garner-tasks paradigm

Among the most fundamental results in the area of perceptual classification are the “correlated facilitation” and “filtering interference” effects observed in Garner’s (1974) speeded categorization tasks: In the case of integral-dimension stimuli, relative to a control task, single-dimension classification is faster when there is correlated variation along a second dimension, but slower when there is orthogonal variation that cannot be filtered out (e.g., by attention). These fundamental effects may result from participants’ use of a trial-by-trial bypass strategy in the control and correlated tasks: The observer changes the previous category response whenever the stimulus changes, and maintains responses if the stimulus repeats. Here we conduct modified versions of the Garner tasks that eliminate the availability of a pure bypass strategy. The fundamental facilitation and interference effects remain, but are still largely explainable in terms of pronounced sequential effects in all tasks. We develop sequence-sensitive versions of exemplar-retrieval and decision-bound models aimed at capturing the detailed, trial-by-trial response-time distribution data. The models combine assumptions involving: (i) strengthened perceptual/memory representations of stimuli that repeat across consecutive trials, and (ii) a bias to change category responses on trials in which the stimulus changes. These models can predict our observed effects and provide a more complete account of the underlying bases of performance in our modified Garner tasks.     

Hard andsoft interacting dimensions: Differential effects of dual context on classification

In this article, we extend Garner’s speeded classification procedure to investigate processes underlying the interaction of the auditory dimensions pitch, loudness, and timbre. In the experiments reported here, subjects classified attributes on these three auditory dimensions. Our extended procedure, calledmulticlass, is based conceptually on our model of how such dimensions interact; the model explains the perception of attributes from an attended dimension through the action of contextual constraints created by variation along an unattended dimension. Two forms of context are present simultaneously in each multiclass task:intraclass context, variation along the unattended dimension that interferes with the classification of attributes, andredundant context, variation along the unattended dimension that enhances classification. We find that such dual-context situations reliably distinguish two kinds of interacting dimensions. Subjects classifying HARD dimensions, here pitch and timbre, resist the ill effects of intraclass.context and reap gains from redundant context. Subjects classifying SOFT dimensions, here loudness, show interference because the attributes are veiled perceptually in dual context, These findings, we argue, demonstrate the power of the multiclass procedure and fit well our view-that dimensional interaction entails processing both at the level of the stimulus whale and at the level of stimulus attributes.     

The effect of redundant stimulus elements on visual discrimination as a function of element heterogeneity,equal discriminability,and position uncertainty

Garner and Lee (1962) showed no gain in visual discrimination accuracy with addition of redundant stimulus elements. Eriksen and Lappin (1965) showed a substantial gain. One experiment reported here indicates that the discrepancy is not due to the fact that the earlier experiment used heterogeneous stimulus elements. A second experiment indicated that the gain in discrimination accuracy does occur when the additional stimulus elements have the same discriminability as the original elements. It also showed that position uncertainty itself has no effect on the gain with redundant elements, but is a convenient procedural device for maintaining fixation and thus equal element discriminability. Three models of perceptual independence fit the data.     

Interference Effects of Contextual Cues in Advertisements on Memory for Ad Content

The effectiveness of advertisements has been an issue of great concern to marketers, especially with the rapid increase in the number of marketing communications that the average consumer receives every day. Prior research has examined the impact of verbal interference on consumers’ memory for different elements of the advertisement—that is, interference caused by similar verbal elements in advertisements for brands in the same product category. This study examined the impact of similar contextual or background stimuli on consumers’ memory for different elements of the advertisement. Consumers were exposed to print advertisements for products in different product categories. The similarity of contextual cues—that is, background scenes—was manipulated (similar vs. dissimilar). Using a 2 (contextual cues interference: low and high) x 2 (processing goal: ad and brand) x 3 (cues: brand name, ad photo, product class) between‐subjects design, it was found that exposure to ads with similar contextual elements reduced individuals’ ability to recall not only contextual or background elements but also brand name from a target advertisement.     

Stroop can occur without Garner interference: Strategic and mandatory influences in multidimensional stimuli

Stroop and Garner interference were studied in two experiments involving stimuli with several irrelevant features. Using these stimuli, which were more complex than those usually used in perceptual interference studies, a new phenomenon occurred: Stroop effects without a corresponding Garner interference were obtained in four out of six nontarget conditions, two with local and two with global targets. The effects with local targets were anomalous: on one dimension, incongruous Stroop stimuli were better than congruous ones, while on the other dimension, effects were restricted to a condition in which all nontargets were congruous. With global targets, more consistent cases of Stroop-without-Garner effects were obtained. All Stroop effects were replicated in Experiment 2, in which presentation time was varied. The effects showed a strong dependency on presentation time, in such a way as to suggest a dynamic growth of the percept. The results were interpreted in terms of an interaction between automatic and strategic components of perceptual processes, in agreement with a recently introduced perceptual-organization model, which yields a new interpretation of priming and interference phenomena.     

The effects of number of sample stimuli and number of choices in a detection task on measures of discriminability

Six pigeons were trained on a conditional discrimination task involving the discrimination of various intensities of yellow light. The research asked whether stimulus—response discriminability measures between any pair of stimuli would remain constant when a third or fourth sample and reinforced response were added. The numbers of different sample stimuli presented and different responses reinforced were two (Part 1), three (Parts 2 and 4), and four (Part 3). Across conditions within parts, the ratios of reinforcers obtainable for correct responses were varied over at least five levels. In Part 5, the numbers of sample stimuli and reinforced responses were varied among two, three, and four, and the reinforcer ratio between consecutive remaining samples was constant at 2:1. It was found that once a particular response had been reinforced, subjects continued to emit that response when the conditional stimulus for that response was no longer presented. Data analysis using a generalization-based detection model indicated that this model was able to describe the data effectively. Four findings were in accord with the theory. First, estimates of stimulus—response discriminability usually decreased as the arranged physical disparity between the sample stimuli decreased. Second, stimulus—response discriminability measures were independent of response—reinforcer discriminability measures, preserving parameter invariance between these measures. Third, stimulus—response discriminability measures for constant pairs of conditional stimuli did not change systematically as conditional stimulus—response alternatives were added. Fourth, log stimulus—response discriminability values between physically adjacent conditional stimuli summed to values that were not significantly different from estimates of the discriminability values for conditional stimuli that were spaced further apart.     

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.