Multistable syllables as enacted percepts: a source of an asymmetric bias in the verbal transformation effect

Perceptual changes are experienced during rapid and continuous repetition of a speech form, leading to an auditory illusion known as the verbal transformation effect. Although verbal transformations are considered to reflect mainly the perceptual organization and interpretation of speech, the present study was designed to test whether or not speech production constraints may participate in the emergence of verbal representations. With this goal in mind, we examined whether variations in the articulatory cohesion of repeated nonsense words--specifically, temporal relationships between articulatory events--could lead to perceptual asymmetries in verbal transformations. The first experiment displayed variations in timing relations between two consonantal gestures embedded in various nonsense syllables in a repetitive speech production task. In the second experiment, French participants repeatedly uttered these syllables while searching for verbal transformation. Syllable transformation frequencies followed the temporal clustering between consonantal gestures: The more synchronized the gestures, the more stable and attractive the syllable. In the third experiment, which involved a covert repetition mode, the pattern was maintained without external speech movements. However, when a purely perceptual condition was used in a fourth experiment, the previously observed perceptual asymmetries of verbal transformations disappeared. These experiments demonstrate the existence of an asymmetric bias in the verbal transformation effect linked to articulatory control constraints. The persistence of this effect from an overt to a covert repetition procedure provides evidence that articulatory stability constraints originating from the action system may be involved in auditory imagery. The absence of the asymmetric bias during a purely auditory procedure rules out perceptual mechanisms as a possible explanation of the observed asymmetries.     

The time course of preview search with color-defined, not luminance-defined, stimuli

We examined the time course of preview search, using stimuli that were defined by color, but not by luminance changes. We demonstrate that, under these conditions, search performance in a preview condition improved selectively over time, relative to a baseline condition in which all the items appeared together. The data confirm earlier reports from Humphreys, Kyllinsbaek, et al. (2004) and Watson and Humphreys (1997), who used luminance-defined stimuli and showed a long time course to preview search. The data contradict Donk and Verburg (2004), who argued that the preview benefit was instantaneous but did not include baseline conditions with which to test for any influence of distractors equivalent to the old items in preview search, even under nonpreview conditions. The data support the proposal that the prioritization of new items in preview search is a time-consuming business.     

A controlled trial of cognitive-behavior therapy combined with vestibular rehabilitation in the treatment of dizziness

Dizziness is a common and often untreated symptom in the general population. The aim of this study was to investigate the effects of a combined cognitive-behavioral/vestibular rehabilitation (VR) program, using a randomized control design. A total of 29 participants were randomized to treatment consisting of psychoeducation, vestibular exercises, relaxation and cognitive interventions, or to serve as waiting list controls. Measures of dizziness-related handicap, dizziness-provoking movements, and daily diary registrations of dizziness symptoms at pre- and post-treatment showed statistically significant improvements in many domains, which translated to moderate effect sizes. These findings provide preliminary support for the combination of Cognitive-behavioral therapy (CBT) and VR methods in the treatment of dizziness.     

Theory-based categorization under speeded conditions

It is widely accepted that similarity influences rapid categorization, whereas theories can influence only more leisurely category judgments. In contrast, we argue that it is not the type of knowledge used that determines categorization speed, but rather the complexity of the categorization processes. In two experiments, participants learned four categories of items, each consisting of three causally related features. Participants gave more weight to cause features than to effect features, even under speeded response conditions. Furthermore, the time required to make judgments was equivalent, regardless of whether participants were using causal knowledge or base-rate information. We argue that both causal knowledge and base-rate information, once precompiled during learning, can be used at roughly the same speeds during categorization, thus demonstrating an important parallel between these two types of knowledge.     

Input control processes in rapid serial visual presentations: target selection and distractor inhibition

The attentional blink refers to the finding that the 2nd of 2 targets embedded in a stream of rapidly presented distractors is often missed. Whereas most theories of the attentional blink focus on limited-capacity processes that occur after target selection, the present work investigates the selection process itself. Identifying a target letter caused an attentional blink for the enumeration of subsequent dot patterns, but this blink was reduced when the dots shared their color with the target letter. In contrast, performance worsened when the color of the dots matched that of the remaining distractors in the stream. Similarity between the targets also affected competition between different sets of dots presented simultaneously within a single display. The authors conclude that the selection of targets from a rapid serial visual presentation stream is mediated by both excitatory and inhibitory attentional control mechanisms.     

Protecting threatened identity: sticking with the group by emphasizing ingroup heterogeneity

In two studies (Ns=163, 164), the authors tested the prediction that perceptions of group variability can steer and guide the way that loyalty is expressed in times of identity threat. In both studies, participants were classified as lower or higher identifiers on the basis of their scores on a group identification measure, and manipulations involved group variability perceptions (homogeneous ingroup vs. heterogeneous ingroup) and threat to the ingroup. Higher identifiers presented with a homogeneous ingroup perceived more ingroup homogeneity under threat than when there was no threat. In contrast, higher identifiers who perceived the ingroup initially as heterogeneous perceived more ingroup heterogeneity under threat than in no threat conditions. Lower identifiers perceived more ingroup heterogeneity under threat (vs. no threat) irrespective of manipulated group variability perceptions. Discussion focuses on different ways that group loyalty can be expressed in times of identity threat.     

Unconscious manipulation of free choice in humans

Previous research has shown that subliminally presented stimuli accelerate or delay responses afforded by supraliminally presented stimuli. Our experiments extend these findings by showing that unconscious stimuli even affect free choices between responses. Thus, actions that are phenomenally experienced as freely chosen are influenced without the actor becoming aware of the manipulation. However, the unconscious influence is limited to a response bias, as participants chose the primed response only in up to 60% of the trials. LRP data in free choice trials indicate that the prime was not ineffective in trials in which participants chose the non-primed response as then it delayed performance of the incongruently primed response.     

Relevant distractors do not cause negative priming

Highly relevant stimuli (such as one’s own name) can capture attention in situations in which one can only partially attend to the environment (e.g., the classic “cocktail party” phenomenon, introduced by Moray, 1959). The present study extends previous findings on selection tasks demonstrating these intrusions of relevant stimuli. Not only can highly relevant stimuli be detected more easily, but attempts to deliberately ignore them will also be hampered, so subsequent reactions to such stimuli will not be slowed. In the experiment, participants (N = 32) ignored the first names of other participants without problems, and they showed slowed reactions to such names that they had ignored shortly before (negative priming task). In contrast, no slowing was observed for participants’ own names when those names had just previously been used as distractors.     

Effect of theory-based feature correlations on typicality judgments

In the present study, we examine what types of feature correlations are salient in our conceptual representations. It was hypothesized that of all possible feature pairs, those that are explicitly recognized as correlated (i.e., explicit pairs) and affect typicality judgments are the ones that are more likely theory based than are those that are not explicitly recognized (i.e., implicit pairs). Real-world categories and their properties, taken from Malt and Smith (1984), were examined. We found that explicit pairs had a greater number of asymmetric dependency relations (i.e., one feature depends on the other feature, but not vice versa) and stronger dependency relations than did implicit pairs, which were statistically correlated in the environment but were not recognized as such. In addition, people more often provided specific relation labels for explicit pairs than for implicit pairs; these labels were most often causal relations. Finally, typicality judgments were more affected when explicit correlations were broken than when implicit correlations were broken. It is concluded that in natural categories, feature correlations that are explicitly represented and affect typicality judgments are the ones about which people have theories.