Do Unilateral Right and Left Face Contractions Induce Positive and Negative Emotions? A Further Test of Schiff and Lamon's (1989) Hypothesis

Schiff and Lamon (1989) proposed that unilateral face contractions induce positive or negative changes in emotion depending on the side of contraction; support for this proposal, however, has been mixed. In a new test, 40 right-handed and 38 left-handed men performed four alternating face contractions (LRLR or RLRL) and, after each one, completed a different version of the Depression Adjective Checklist (Lubin, 1994). A repeated-measures ANCOVA failed to reveal any significant effect of side of face contraction or handedness on direction of emotion change. Instead, regardless of side of contraction, the subjects' negative emotional state increased significantly across the four contractions with the degree of change being significantly related to the subjects' reported level of difficulty in holding the contraction irrespective of whether the more difficult side was the left or the right.     

Pure word deafness and the bilateral processing of the speech code

The analysis of pure word deafness (PWD) suggests that speech perception, construed as the integration of acoustic information to yield representations that enter into the linguistic computational system, (i) is separable in a modular sense from other aspects of auditory cognition and (ii) is mediated by the posterior superior temporal cortex in both hemispheres. PWD data are consistent with neuropsychological and neuroimaging evidence in a manner that suggests that the speech code is analyzed bilaterally. The typical lateralization associated with language processing is a property of the computational system that acts beyond the analysis of the input signal. The hypothesis of the bilateral mediation of the speech code does not imply that both sides execute the same computation. It is proposed that the speech signal is asymmetrically analyzed in the time domain, with left‐hemisphere mechanisms preferentially extracting information over shorter (25–50 ms) temporal integration windows and right mechanisms over longer (150–250 ms) windows.     

A theory of the visual system biology underlying development of spatial frequency lateralization

The spatial frequency hypothesis contends that performance differences between the hemispheres on various visuospatial tasks are attributable to lateralized processing of the spatial frequency content of visual stimuli. Hellige has proposed that such lateralization could arise during infant development from the earlier maturation of the right hemisphere combined with the increasing sensitivity of the visual system to high spatial frequencies. This proposal is intuitively appealing but lacks an explicit theory with respect to the underlying visual system biology. In this paper, we develop such a theory based on knowledge of visual system processing and development. We then translate our theory into a computational model that serves as the basis for a series of development simulations. We find that the simulations produce spatial frequency lateralization effects consistent with those observed empirically. We relate the nature of the neural asymmetry implied by our theory to empirical findings on visual pathway bias and the relative spatial frequency lateralization effect.     

Individual differences in risk perception versus risk taking: handedness and interhemispheric interaction

Research indicates that right-hemisphere mechanisms are specifically sensitive to and averse to risk. Research also indicates that mixed degree of handedness is associated with increased access to right hemisphere processing. Accordingly, it was predicted that mixed-handers would exhibit greater risk aversion. Participants were presented with various risky activities and were asked to rate (i) the perceived risk, (ii) the perceived benefit, and (iii) their likelihood to engage in each activity. No handedness differences were found for any of these ratings. Regression analyses, however, indicated that the likelihood to engage in risky activities was predicted primarily by the perceived risks in mixed-handers and by the perceived benefits in strong-handers.     

Does game pressure affect hand selection of NBA basketball players?

PurposeThe purpose of this study was to compare hand selection and accuracy of technical skills between low- and high-pressure games of the National Basketball Association (NBA) in the 2018–2019 regular season and playoffs.MethodA notational analysis was conducted on 24 games of four teams (12 low-pressure games and 12 high-pressure games, six of each team, three in each condition). One- or two-handed actions were recorded for dribbling, passing, catching, and shooting (layups, dunks, hooks, and tips) skills.ResultsDuring high-pressure games, players significantly increased the frequency of right-handed passing. High-pressure games also increased the frequency of left-handed catching. For dribbling and shooting, no differences were observed in hand frequency between conditions. The success rate of all analyzed skills was similar between the hands in both low- and high-pressure conditions.ConclusionOur results showed that game pressure could selectively modulate hand preference for passing and catching skills in elite-level basketball while presenting no significant effect on performance between hands.     

Hemispheric laterality measured in Rembrandt's portraits using pupil diameter and aesthetic verbal judgements

Eckhard Hess claimed that pupils dilate to pleasant images and constrict to unpleasant images. However, his work was confounded since his image's luminances and contrasts across conditions were inconsistent. We overcome this limitation and suggest a new, promising methodology for research in this area. We presented rightward or leftward facing male and female portraits by Rembrandt to observers in either their original or mirror-reversed position. Since emotional content may be expressed differently on each side of the face, we used Rembrandt's portraits since most of his males had their right-cheek exposed and females had their left-cheek exposed. This raises questions regarding the emotional and cognitive significance of such biased positioning. Simultaneously, we measured observers pupil size while asking observers to report how (dis)pleasing they found each image. We found that in viewing male portraits pupil diameter was a function of arousal. That is, larger pupil diameter occurred for images rated both low and high in pleasantness. We discuss these findings in regard to the perceived dominance of males and how emotional expressions may be driven by hemispheric laterality.     

Decrease of prefrontal-posterior EEG coherence: loose control during social-emotional stimulation

In two experiments we aimed to investigate if individual differences in state-dependent decreases or increases of EEG coherence between prefrontal and posterior cortical regions may be indicative of a mechanism modulating the impact social-emotional information has on an individual. Two independent samples were exposed to an emotional stimulation paradigm in which the participants were invited to get involved and sympathize with the persons they were watching (study 1) or listening to (study 2), and who were expressing sadness or anxiety. The two studies yielded consistent results. Higher scores in trait absorption and in the propensity to ruminate were associated with decreased EEG beta coherence during the stimulation, whereas coherence increased in individuals low in absorption or rumination. Coherence changes did not predict to which degree the participants felt infected by the displayed emotions, but in individuals showing decreased prefrontal-posterior coupling during the stimulation, feelings of sadness and anxiety had a greater tendency to persist. The findings suggest that more loose prefrontal-posterior coupling may be related to loosening of control of the prefrontal cortex over incoming social-emotional information and, consequently, to deeper emotional involvement and absorption, whereas increased prefrontal-posterior coupling may be related to strong control, dampening of emotional experience, and not letting oneself become emotionally affected.     

Hemisphere-dependent holistic processing of familiar faces

In two behavioral experiments involving lateralized stimulus presentation, we tested whether one of the most commonly used measures of holistic face processing—the composite face effect—would be more pronounced for stimuli presented to the right as compared to the left hemisphere. In experiment 1, we investigated the composite face effect in a verbal identification task, similar to its original report (Young, Hellawell, & Hay, 1987). Aligning top and bottom halves of composite face stimuli led to performance decreases irrespective of hemifield, indicating holistic processing of comparable magnitude for inputs provided separately to either hemisphere. However, when matching of the same top parts was required in experiment 2, an alignment-dependent performance decrease was found for stimuli presented in the left, but not right visual field. These observations suggest that the right hemisphere dominates in early stages of holistic processing, as indexed by the composite face effect, but that later processes such as face identification and naming are based on unified representations that are independent of input lateralization. Moreover, the composite face effect may not rely on the exact same representation(s) when measured in matching and identification tasks.     

Left-view sequences of faces are superior to right-view ones for view generalization

Faces learned from multiple viewpoints are recognized better with left than right three-quarter views. This left-view superiority could be explained by perceptual experience, facial asymmetry, or hemispheric specialization. In the present study, we investigated whether left-view sequences are also more effective in recognizing same and novel views of a face. In a sequential matching task, a view sequence showing a face rotating around a left (?30°) or a right (+30°) angle, with an amplitude of 30°, was followed by a static test view with the same viewpoint as the sequence (?30° or +30°) or with a novel one (0°, +30°, or ?30°). We found a superiority of left-view sequences independently of the test viewpoint, but no superiority of left over right test views. These results do not seem compatible with the perceptual experience hypothesis, which predicts superiority only for left-side test views (?30°). Also, a facial asymmetry judgement task showed no correlation between the asymmetry of individual faces and the left-view sequence superiority. A superiority of left-view sequences for novel as well as same test views argues in favour of an explanation by hemispheric specialization, because of the possible role of the right hemisphere in extracting facial identity information.     

The effects of attention on ear advantages in dichotic listening to words and affects

This study examined the effects of attention on ear advantages using dichotic listening to words and affects, a focused-attention paradigm. We compared the mixed condition, in which attention is switched between the ears in each trial, to the blocked condition, in which attention is directed to one ear for an entire block of trials. Results showed a decreased right ear advantage for word processing only in the mixed condition and an increased left ear advantage for emotion processing in both attention conditions for hits index. The mixed condition showed smaller laterality effects than the blocked condition for words with respect to hits index, while increasing right ear predominance for intrusions. The greater percentage of intrusions in the right ear for the word task and in the mixed condition suggests that the right ear (left hemisphere) is most vulnerable to attention switching. We posit that the attention manipulation has a greater effect on word processing than on emotion processing and propose that ear advantages reflect a combination of the effects of attentional and structural constraints on lateralisation.