Positive-negative asymmetry and bipolar contrast

Abstract

Repertory grids in which personal acquaintances were evaluated on the basis of bipolar constructs (e.g., generous-stingy) were completed by 58 undergraduates. A “person format”, with all constructs applied to each acquaintance in turn, was assigned randomly to 29 students; a “construct format”, in which these acquaintances were evaluated successively on only 1 construct at a time, was assigned to the other 29. The relative frequency of positive evaluations in the construct format grids (0.62) was consistent with the golden section hypothesis, whereas that in the person format grids (0.66) was significantly higher. Theoretical implications of these findings were discussed in terms of H. Frank's (1964) theoretical definition of strikingness and V. A. Lefebvre's (1990) computational model of reflexion.     

Ear asymmetry in perception of emotional non-verbal stimuli

Hemispheric asymmetry for perception of non-verbal emotional human voices was investigated in normal subjects by dichotic listening utilizing non-verbal responses. As in former experiments, a slight but significant left ear superiority was found. This finding suggests that mediation of these stimuli is done by the right hemisphere. The dominant role of the right hemisphere in this perceptual task is discussed in terms of an earlier development of this hemisphere.     

Lateral asymmetry in the perceived sequence of speech and nonspeech stimuli

The task was to estimate the position where a click had been superimposed in a spoken sentence. Experiment 1 confirmed Fodor and Bever’s observation of an ear-asymmetry effect: the click is located earlier when it is presented to the left ear and the sentence to the right ear than with the opposite arrangement. In Experiment 2, combinations of monaural and binaural presentations were considered. They made it possible to eliminate interpretations which link the laterality effect to the fact of reaching or not reaching a particular ear and showed that the relevant factor is the relative position of the stimuli in acoustic space. Experiments 3 and 4 explored the relation between spatial separation and perceived sequence in greater detail. The relation involves a plateau: when the click comes to the left of the speech, it is preposed to a degree which depends on the amount of spatial separation; but, when it comes to the right of the speech, separation is irrelevant and the mean error is of the same order of magnitude as in a control condition without separation.     

Intention matters to make you (im)moral: Positive-negative asymmetry in moral character evaluations

ABSTRACT

Is intention, even if unfulfilled, enough to make a person appear to be good or bad? In this study, we investigated the influence of unfulfilled intentions of an agent on subsequent moral character evaluations. We found a positive-negative asymmetry in the effect of intentions. Factual information concerning failure to fulfill a positive intention mitigated the morality judgment of the actor, yet this mitigation was not as evident for the negative vignettes. Participants rated an actor who failed to fulfill their negative intention as highly immoral, as long as there was an external explanation to its unfulfillment. Furthermore, both emotional and cognitive (i.e., informativeness) processes mediated the effect of negative intention on moral character. For the positive intention, there was a significant mediation by emotions, yet not by informativeness. Results evidence the relevance of mental states in moral character evaluations and offer affective and cognitive explanations to the asymmetry.     

An experimental study of the asymmetry effect in the method of constant stimuli

Summary The asymmetry effect (AE) in the method of constant stimuli refers to the dependence of the sign and of the magnitude of the constant error on the position of the standard (S) within the range of the variable (V) stimuli. The AE is known to occur when S and V appear in succession. The experiment reported here shows that the AE also occurs when S and V are simultaneous. This result allows us to conclude that the AE is not a memory effect, and that it is plausible to suppose that it depends on a factor of judgment.Research subsidized by CNR     

Development of perceptual asymmetry for free viewing of chimeric stimuli

Free-viewing chimeric stimuli tasks have been used in a number of studies to assess perceptual asymmetries and draw inferences about hemispheric lateralization in children and adults. In order to determine whether perceptual asymmetries for nonverbal information are present in children, a free-viewing chimeric stimuli task was used in 63 normally developing 6- through 16-year-old children. Stimuli included affect (happy faces), gender, quantity, and shape. An overall left hemispace (LHS) advantage was present by 6 years of age. This LHS preference was more prominent by age 10 and then plateaued. No preference for shape was detected at any of the age ranges studied. These results suggest that perceptual asymmetries for visual stimuli develop during childhood and appear to reach a plateau by age 10. The observed specificity for certain types of nonverbal stimuli should be taken into account in future studies of perceptual asymmetry in both normal and neurologically impaired children.     

Electrographic correlates of lateral asymmetry in the processing of verbal and nonverbal auditory stimuli

A veraged evoked potentials (AEP) to verbal (digits) and nonverbal (clicks) auditory stimuli were recorded from left and right temporal leads in ten right-handed Ss. With dichotic presentation, there was no significant difference in accuracy of report of the clicks heard in each ear, but significantly more digits were identified correctly from the right ear than from the left. Dichotic verbal stimuli elicited AEP whose early components were of greater amplitude, and whose later components were of shorter latency, from the left hemisphere than from the right. No consistent latency or amplitude differences were observed between AEP from the left and right hemispheres when clicks were presented dichotically.     

Perceptual asymmetry for chimeric stimuli in children with early unilateral brain damage

The present study used a chimeric stimuli task to assess the magnitude of the left-hemispace bias in children with congenital unilateral brain damage (n = 46) as compared to typically developing matched controls (n = 46). As would be expected, controls exhibited a significant left-hemispace bias. In the presence of left hemisphere (LH) damage, the left-hemispace preference was found to be present, but attenuated, whereas right hemisphere (RH) damage resulted in a less lateralized process. Examination of lesion severity revealed that large lesions in the RH were associated with a reversal of the typical left-hemispace bias, while small lesions resulted in a left bias approximating that of controls. In contrast, the left-hemispace preference in children with LH damage was similar across lesion size. We conclude that damage to either hemisphere early in brain development may alter hemispheric preference for processing of nonverbal stimuli, and that at least in the case of RH damage, alteration of the normal perceptual asymmetry may depend on the interaction between lesion side and severity.     

Cerebral asymmetry for American Sign Language: The effects of moving stimuli

Previous studies of cerebral asymmetry for the perception of American Sign Language (ASL) have used only static representations of signs; in this study we present moving signs. Congenitally deaf, native ASL signers identified moving signs, static representations of signs, and English words. The stimuli were presented rapidly by motion picture to each visual hemifield. Normally hearing English speakers also identified the English words. Consistent with previous findings, both the deaf and the hearing subjects showed a left-hemisphere advantage to the English words; likewise, the deaf subjects showed a right hemisphere advantage to the statically presented signs. With the moving signs, the deaf showed no lateral asymmetry. The shift from right dominance to a more balanced hemispheric involvement with the change from static to moving signs is consistent with Kimura's position that the left hemisphere predominates in the analysis of skilled motor sequencing (Kimura 1976). The results also indicate that ASL may be more bilaterally represented than is English and that the spatial component of language stimuli can greatly influence lateral asymmetries.     

The automatic evaluation of novel stimuli

From classic theory and research in psychology, we distill a broad theoretical statement that evaluative responding can be immediate, unintentional, implicit, stimulus based, and linked directly to approach and avoidance motives. This statement suggests that evaluative responses should be elicited by novel, nonrepresentational stimuli (e.g., abstract art, "foreign" words). We tested this hypothesis through combining the best features of relevant automatic–affect research paradigms. We first obtained explicit evaluative ratings of novel stimuli. From these, we selected normatively positive and negative stimuli to use as primes in a sequential priming paradigm. Two experiments using this paradigm demonstrated that briefly presented novel prime stimuli were evaluated automatically, as they facilitated responses to subsequently presented target stimuli of the same valence just as much as did pictures or names of real objects. A final experiment revealed that exposure to novel stimuli produces muscular predispositions to approach or avoid them.     

The good,the bad,and the trivial

Dreadful and dreaded outcomes are sometimes brought about via the accumulation of individually trivial effects. Think about inching toward terrible health or toward an environmental disaster. In some such cases, the outcome is seen as unacceptable but is still gradually realized via an extended sequence of moves each of which is trivial in terms of its impact on the health or environment of those involved. Cases of this sort are not only practically challenging, they are theoretically challenging as well. For, they raise puzzling complications concerning the assessment of conduct. In particular, given cases of this sort, we seem forced to conclude that, sometimes, each current doing in an extended sequence of moves can be correctly assessed as permissible (relative to a certain set of concerns) even though the sequence foreseeably leads to an outcome that is unacceptable (relative to that same set of concerns) and even though acceptable outcomes are available. And this seems paradoxical. I argue that this (apparent) puzzle glosses over complications associated with action individuation and units of agency. Reflection on these complications makes it clear that in cases of the sort that have given rise to the puzzle, there is an accurate way of seeing what is being done at various particular moments that clearly brings out the tight connection between a current doing and non-trivial damage that is to be expected (and is indeed bound to occur if the doing is completed without a hitch).     

An ERP index of task relevance evaluation of visual stimuli

Recently several event-related potential attention studies have described a prefrontal positivity at about the same latency as the posterior N2 (approximately 200-300 ms), variously termed the frontal selection positivity (FSP), the anterior P2 (P2a), or the frontal P3 (P3f). These components have a similar spatio-temporal distribution and similar eliciting properties, suggesting that they represent the same component. However, these components have been differentially interpreted as arising from neural systems of feature selection, stimulus evaluation, or response production. The present study employed a visual target detection (oddball) design with different response conditions: passive (no response), overt (keypress), and covert (silent count), to examine the impact of task relevance and response production on the frontal P2a. The results showed that the P2a was present to task-relevant stimuli but had the same scalp topography and estimated source-dipole locations in both overt and covert responding, indicative of an index of stimulus evaluation, rather than response production.     

Effect of facial stimuli exposure time on evaluation of facial attractiveness

Facial attractiveness has advantages both socially and sexually, and the human brain has evolved to perceive specific facial characteristics as attractive. The current research examined the effect of facial stimuli exposure time on facial attractiveness evaluations. In Experiment 1, 86 students observed 44 facial stimuli in short and long amounts of time. To eliminate any influence of repeated stimuli on the second observations, Experiment 2 was performed on 84 participants who observed the facial stimuli in either short or long durations. Differences in both experiments were significant. These studies showed that exposure time has an influence on the evaluation of facial attractiveness. Participants who were exposed to facial stimuli for a short amount of time perceived greater facial attractiveness than when they were exposed for a longer time to the same stimuli. In other words, faces were more beautiful when they were observed in a short amount of time, and this effect occurred regardless of gender.