Who goes where in couples and pairs? Effects of sex and handedness on side preferences in human dyads.

There is increasing evidence that inter-individual interaction among conspecifics can cause population-level lateralization. Male-female and mother-infant dyads of several non-human species show lateralised position preferences, but such preferences have rarely been examined in humans. We observed 430 male-female human pairs and found a significant bias for males to walk on the right side of the pair. A survey measured side preferences in 93 left-handed and 92 right-handed women, and 96 left-handed and 99 right-handed men. When walking, and when sitting on a bench, males showed a significant side preference determined by their handedness, with left-handed men preferring to be on their partner's left side and right-handed men preferring to be on their partner's right side. Women did not show significant side preferences. When men are with their partner they show a preference for the side that facilitates the use of their dominant hand. We discuss possible reasons for the side preference, including males prefering to occupy the optimal "fight ready" side, and the influence of sex and handedness on the strength and direction of emotion lateralization.

The effects of sex and handedness on masturbation laterality and other lateralized motor behaviours.

Masturbation is a common human behaviour. Compared to other unimanual behaviours it has unique properties, including increased sexual and emotional arousal, and privacy. Self-reported hand preference for masturbation was examined in 104 left-handed and 103 right-handed women, and 100 left-handed and 99 right-handed men. Handedness (modified Edinburgh Handedness Inventory, EHI), footedness, eyedness, and cheek kissing preferences were also measured. Seventy nine percent used their dominant hand (always/usually) for masturbation, but left-handers (71.5%) were less consistently lateralized to use their dominant hand than right-handers (86.5%). Hand preference for masturbation correlated more strongly with handedness (EHI), than with footedness, eyedness, or cheek preference. There was no difference in masturbation frequency between left- and right-handers, but men masturbated more frequently than women, and more women (75%) than men (33%) masturbated with sex aids. For kissing the preferred cheek of an emotionally close person from the viewer's perspective, left-handers showed a left-cheek preference, and right-handers a weaker right-cheek preference. The results suggest that hemispheric asymmetries in emotion do not influence hand preference for masturbation but may promote a leftward shift in cheek kissing. In all, masturbation is lateralized in a similar way to other manual motor behaviours in left-handed and right-handed men and women.

Limb preference and personality in donkeys (Equus asinus).

Interhemispheric laterality has often been linked to different behavioural styles. This study investigates the link between limb preference and personality in donkeys. The sample consisted of 47 donkeys (Equus asinus), 30 males and 17 females. Limb preference was determined using observation of the leading limb in a motionless posture and personality was measured using the Donkey Temperament Questionnaire (French, J. M. (1993). Assessment of donkey temperament and the influence of home environment. Applied Animal Behaviour Science, 36(2), 249-257. doi:10.1016/0168-1591(93)90014-G) completed by the donkeys' keepers. A Principal Component Analysis obtained two components: Agreeableness and Extraversion. Age showed a positive relationship with Agreeableness, echoing trends in humans Donkeys did not show a population-level preference towards either side. Limb preference significantly predicted the trait difficult to handle: donkeys with a preference to keep the right foot forward when motionless were harder to handle. This study presents the first investigation into limb preference and personality in donkeys, although more research is needed to clarify whether there is a population-level limb preference bias in donkeys, and the relationship between limb preference and Agreeableness.

Concreteness of semantic interpretations of abstract and representational artworks.

The authors tested two contrasting theoretical predictions to establish whether semantic interpretations of abstract artworks had different lexical concreteness from those of representational artworks. In Experiment 1, 49 non-expert participants provided brief verbal interpretations of 20 abstract and 20 representational artworks. Frequentist and Bayesian Linear Mixed Models showed that the words' concreteness levels were robustly higher for interpretations of abstract artworks than representational artworks. This difference was present regardless of the inclusion or exclusion of function words. Potential diluting or inflating impacts on the effect due to the multi-word responses were examined in Experiment 2, in which 72 new participants provided single-word interpretations for the same artworks. The effect replicated with a larger effect size. The findings suggest that non-expert viewers prioritise establishing what is depicted over seeking deeper meanings if the depicted is not readily established perceptually. The findings are incompatible with the theoretical stance that abstract art has abstract meaning. Instead, the findings are consistent with complex models of aesthetic processing in which meaning may emerge in stages. The effect of art type on the concreteness of meaning is an important, hitherto undiscovered basic finding in empirical aesthetics. Our novel methods enable further research in this field.

A leftward bias for the arrangement of consumer items that differ in attractiveness.

People are frequently biased to use left-side information more than right-side information to inform their perceptual judgements. This research examined whether the leftward bias also applied to preferences for the arrangement of everyday consumer items. Pairs of consumer items were created where one item was more attractive than the other item. Using a two-alternative forced choice task, Experiment 1 found a robust preference for arrangements with the more attractive consumer item on the left side rather than the right side of a pair. Experiment 2 reversed the judgement decision, with participants asked to choose the arrangement they least preferred, and a bias for arrangements with the more attractive item on the right side emerged. Experiment 3 failed to find an effect of the "attractive left" preference on participants' purchasing intentions. The preference for attractive left arrangements has implications for the display of consumer products and for the aesthetic arrangement of objects in general. The findings are discussed in relation to hemispheric asymmetries in processing and the role of left to right scanning.

Initial validation of the general attitudes towards Artificial Intelligence Scale.

A new General Attitudes towards Artificial Intelligence Scale (GAAIS) was developed. The scale underwent initial statistical validation via Exploratory Factor Analysis, which identified positive and negative subscales. Both subscales captured emotions in line with their valence. In addition, the positive subscale reflected societal and personal utility, whereas the negative subscale reflected concerns. The scale showed good psychometric indices and convergent and discriminant validity against existing measures. To cross-validate general attitudes with attitudes towards specific instances of AI applications, summaries of tasks accomplished by specific applications of Artificial Intelligence were sourced from newspaper articles. These were rated for comfortableness and perceived capability. Comfortableness with specific applications was a strong predictor of general attitudes as measured by the GAAIS, but perceived capability was a weaker predictor. Participants viewed AI applications involving big data (e.g. astronomy, law, pharmacology) positively, but viewed applications for tasks involving human judgement, (e.g. medical treatment, psychological counselling) negatively. Applications with a strong ethical dimension led to stronger discomfort than their rated capabilities would predict. The survey data suggested that people held mixed views of AI. The initially validated two-factor GAAIS to measure General Attitudes towards Artificial Intelligence is included in the Appendix.

A leftward perceptual asymmetry when judging the attractiveness of visual patterns.

Perceptual judgements concerning the magnitude of a stimulus feature are typically influenced more by the left side of the stimulus than by the right side. This research examined whether the leftward bias also applies to judgements of the attractiveness of abstract visual patterns. Across four experiments participants chose between two versions of a stimulus which either had an attractive left side or an attractive right side. Experiments 1 and 2 presented artworks and experiments 3 and 4 presented wallpaper designs. In each experiment participants showed a significant bias to choose the stimulus with an attractive left side more than the stimulus with an attractive right side. The leftward bias emerged at age 10/11, was not caused by a systematic asymmetry in the perception of colourfulness or complexity, and was stronger when the difference in attractiveness between the left and right sides was larger. The results are relevant to the aesthetics of product and packaging design and show that leftward biases extend to the perceptual judgement of everyday items. Possible causes of the leftward bias for attractiveness judgements are discussed and it is suggested that the size of the bias may not be a measure of the degree of hemispheric specialization.

Right-ear precedence and vocal emotion contagion: The role of the left hemisphere.

Much evidence suggests that the processing of emotions is lateralized to the right hemisphere of the brain. However, under some circumstances the left hemisphere might play a role, particularly for positive emotions and emotional experiences. We explored whether emotion contagion was right-lateralized, lateralized valence-specifically, or potentially left-lateralized. In two experiments, right-handed female listeners rated to what extent emotionally intoned pseudo-sentences evoked target emotions in them. These sound stimuli had a 7 ms ear lead in the left or right channel, leading to stronger stimulation of the contralateral hemisphere. In both experiments, the results revealed that right ear lead stimuli received subtly but significantly higher evocation scores, suggesting a left hemisphere dominance for emotion contagion. A control experiment using an emotion identification task showed no effect of ear lead. The findings are discussed in relation to prior findings that have linked the processing of emotional prosody to left-hemisphere brain regions that regulate emotions, control orofacial musculature, are involved in affective empathy processing areas, or have an affinity for processing emotions socially. Future work is needed to eliminate alternative interpretations and understand the mechanisms involved. Our novel binaural asynchrony method may be useful in future work in auditory laterality.

Reachability Does Not Explain the Middle Preference: A Comment on Bar-Hillel (2015).

Choosing an object from an array of similar objects is a task that people complete frequently throughout their lives (e.g., choosing a can of soup from many cans of soup). Research has also demonstrated that items in the middle of an array or scene are looked at more often and are more likely to be chosen. This middle preference is surprisingly robust and widespread, having been found in a wide range of perceptual-motor tasks. In a recent review of the literature, Bar-Hillel (2015) proposes, among other things, that the middle preference is largely explained by the middle item being easier to reach, either physically or mentally. We specifically evaluate Bar-Hillel's reachability explanation for choice in non-interactive situations in light of evidence showing an effect of item valence on such choices. This leads us to conclude that the center-stage heuristic account is a more plausible explanation of the middle preference.

The Development of Shared Liking of Representational but not Abstract Art in Primary School Children and Their Justifications for Liking.

Understanding how aesthetic preferences are shared among individuals, and its developmental time course, is a fundamental question in aesthetics. It has been shown that semantic associations, in response to representational artworks, overlap more strongly among individuals than those generated by abstract artworks and that the emotional valence of the associations also overlaps more for representational artworks. This valence response may be a key driver in aesthetic appreciation. The current study tested predictions derived from the semantic association account in a developmental context. Twenty 4-, 6-, 8- and 10-year-old children (n = 80) were shown 20 artworks (10 representational, 10 abstract) and were asked to rate each artwork and to explain their decision. Cross-observer agreement in aesthetic preferences increased with age from 4-8 years for both abstract and representational art. However, after age 6 the level of shared appreciation for representational and abstract artworks diverged, with significantly higher levels of agreement for representational than abstract artworks at age 8 and 10. The most common justifications for representational artworks involved subject matter, while for abstract artworks formal artistic properties and color were the most commonly used justifications. Representational artwork also showed a significantly higher proportion of associations and emotional responses than abstract artworks. In line with predictions from developmental cognitive neuroscience, references to the artist as an agent increased between ages 4 and 6 and again between ages 6 and 8, following the development of Theory of Mind. The findings support the view that increased experience with representational content during the life span reduces inter-individual variation in aesthetic appreciation and increases shared preferences. In addition, brain and cognitive development appear to impact on art appreciation at milestone ages.

Right-lateralized unconscious, but not conscious, processing of affective environmental sounds.

Much research on the laterality of affective auditory stimuli features emotional speech. However, environmental sounds can also carry affective information, but their lateralized processing for affect has been studied much less. We studied this in 2 experiments. In Experiment 1 we explored whether the detection of affective environmental sounds (from International Affective Digital Sounds) that appeared in auditory scenes was lateralized. While we found that negative targets were detected more rapidly, detection latencies were the same on the left and right. In Experiment 2 we examined whether conscious appraisal of the stimulus was needed for lateralization patterns to emerge, and asked participants to rate the stimuli's pleasantness in a dichotic listening test. This showed that when positive/negative environmental sounds were in the attended to-be-rated channel, ratings were the same regardless of laterality. However, when participants rated neutral stimuli and the unattended channel was positive/negative, the valence of the unattended channel affected the neutral ratings more strongly with left ear (right hemisphere, RH) processing of the affective sound. We link our findings to previous work that suggests that the RH may specialize in the unconscious processing of emotion via subcortical routes.

Greater cross-viewer similarity of semantic associations for representational than for abstract artworks.

It has been shown previously that liking and valence of associations in response to artworks show greater convergence across viewers for representational than for abstract artwork. The current research explored whether the same applies to the semantic content of the associations. We used data gained with an adapted unique corporate association valence measure, which invited 24 participants to give short verbal responses to 11 abstract and 11 representational artworks. We paired the responses randomly to responses given to the same artwork and computed semantic similarity scores using UMBC Ebiquity software. This showed significantly greater semantic similarity scores for representational than for abstract art. A control analysis in which responses were randomly paired with responses from the same category (abstract, representational) showed no significant results, ruling out a baseline effect. For both abstract and representational artworks, randomly paired responses resembled each other less than responses from the same artworks, but the effect was much larger for representational artworks. Our work shows that individuals share semantic associations with other viewers in response to artworks to a greater extent when the artwork is representational than when it is abstract. Our novel method shows potential utility for many areas of psychology that aim to understand the semantic convergence of people's verbal responses, not least aesthetic psychology.

Shared liking and association valence for representational art but not abstract art.

We examined the finding that aesthetic evaluations are more similar across observers for representational images than for abstract images. It has been proposed that a difference in convergence of observers' tastes is due to differing levels of shared semantic associations (Vessel & Rubin, 2010). In Experiment 1, student participants rated 20 representational and 20 abstract artworks. We found that their judgments were more similar for representational than abstract artworks. In Experiment 2, we replicated this finding, and also found that valence ratings given to associations and meanings provided in response to the artworks converged more across observers for representational than for abstract art. Our empirical work provides insight into processes that may underlie the observation that taste for representational art is shared across individual observers, while taste for abstract art is more idiosyncratic.

Looking behaviour and preference for artworks: the role of emotional valence and location.

The position of an item influences its evaluation, with research consistently finding that items occupying central locations are preferred and have a higher subjective value. The current study investigated whether this centre-stage effect (CSE) is a result of bottom-up gaze allocation to the central item, and whether it is affected by item valence. Participants (n=50) were presented with three images of artistic paintings in a row and asked to choose the image they preferred. Eye movements were recorded for a subset of participants (n=22). On each trial the three artworks were either similar but different, or were identical and with positive valence, or were identical and with negative valence. The results showed a centre-stage effect, with artworks in the centre of the row preferred, but only when they were identical and of positive valence. Significantly greater gaze allocation to the central and left artwork was not mirrored by equivalent increases in preference choices. Regression analyses showed that when the artworks were positive and identical the participants' last fixation predicted preference for the central art-work, whereas the fixation duration predicted preference if the images were different. Overall the result showed that item valence, rather than level of gaze allocation, influences the CSE, which is incompatible with the bottom-up gaze explanation. We propose that the centre stage heuristic, which specifies that the best items are in the middle, is able to explain these findings and the centre-stage effect.

The influence of position and context on facial attractiveness.

It has been shown that a person's position in a group influences how that person is evaluated, with people in the middle perceived as more important than people on the fringe of a group. Four experiments examined whether the position of a face, in a line of five faces, influenced facial attractiveness. The middle position influenced the perceived attractiveness of the target face but the direction of this effect depended on the attractiveness of the target and the surrounding faces. Attractive faces were perceived as less attractive when in the middle of unattractive faces, or faces of average attractiveness. Conversely, unattractive faces were perceived as more attractive when in the middle of other unattractive faces. These results have wide implications, suggesting that the more central a stimulus is in a context then the greater the influence of the context on the judgment of that stimulus.

Valence-specific laterality effects in vocal emotion: interactions with stimulus type, blocking and sex.

Valence-specific laterality effects have been frequently obtained in facial emotion perception but not in vocal emotion perception. We report a dichotic listening study further examining whether valence-specific laterality effects generalise to vocal emotions. Based on previous literature, we tested whether valence-specific laterality effects were dependent on blocked presentation of the emotion conditions, on the naturalness of the emotional stimuli, or on listener sex. We presented happy and sad sentences, paired with neutral counterparts, dichotically in an emotion localisation task, with vocal stimuli being preceded by verbal labels indicating target emotions. The measure was accuracy. When stimuli of the same emotion were presented as a block, a valence-specific laterality effect was demonstrated, but only in original stimuli and not morphed stimuli. There was a separate interaction with listener sex. We interpret our findings as suggesting that the valence-specific laterality hypothesis is supported only in certain circumstances. We discuss modulating factors, and we consider whether the mechanisms underlying those factors may be attentional or experiential in nature.

Identifying facial emotions: valence specific effects and an exploration of the effects of viewer gender.

The valence hypothesis suggests that the right hemisphere is specialised for negative emotions and the left hemisphere is specialised for positive emotions (Silberman & Weingartner, 1986). It is unclear to what extent valence-specific effects in facial emotion perception depend upon the gender of the perceiver. To explore this question 46 participants completed a free view lateralised emotion perception task which involved judging which of two faces expressed a particular emotion. Eye fixations of 24 of the participants were recorded using an eye tracker. A significant valence-specific laterality effect was obtained, with positive emotions more accurately identified when presented to the right of centre, and negative emotions more accurately identified when presented to the left of centre. The valence-specific laterality effect did not depend on the gender of the perceiver. Analysis of the eye tracking data showed that males made more fixations while recognising the emotions and that the left-eye was fixated substantially more than the right-eye during emotion perception. Finally, in a control condition where both faces were identical, but expressed a faint emotion, the participants were significantly more likely to select the right side when the emotion label was positive. This finding adds to evidence suggesting that valence effects in facial emotion perception are not only caused by the perception of the emotion but by other processes.

The effects of advertisement location and familiarity on selective attention.

This study comprised two experiments to examine the distracting effects of advertisement familiarity, location, and onset on the performance of a selective attention task. In Exp. 1, familiar advertisements presented in peripheral vision disrupted selective attention when the attention task was more demanding, suggesting that the distracting effect of advertisements is a product of task demands and advertisement familiarity and location. In Exp. 2, the onset of the advertisement shortly before, or after, the attention task captured attention and disrupted attentional performance. The onset of the advertisement before the attention task reduced target response time without an increase in errors and therefore facilitated performance. Despite being instructed to ignore the advertisements, the participants were able to recall a substantial proportion of the familiar advertisements. Implications for the presentation of advertisements during human-computer interaction were discussed.

Valence specific laterality effects in prosody: expectancy account and the effects of morphed prosody and stimulus lead.

The majority of studies have demonstrated a right hemisphere (RH) advantage for the perception of emotions. Other studies have found that the involvement of each hemisphere is valence specific, with the RH better at perceiving negative emotions and the LH better at perceiving positive emotions [Reuter-Lorenz, P., & Davidson, R.J. (1981) Differential contributions of the 2 cerebral hemispheres to the perception of happy and sad faces. Neuropsychologia, 19, 609-613]. To account for valence laterality effects in emotion perception we propose an 'expectancy' hypothesis which suggests that valence effects are obtained when the top-down expectancy to perceive an emotion outweighs the strength of bottom-up perceptual information enabling the discrimination of an emotion. A dichotic listening task was used to examine alternative explanations of valence effects in emotion perception. Emotional sentences (spoken in a happy or sad tone of voice), and morphed-happy and morphed-sad sentences (which blended a neutral version of the sentence with the pitch of the emotion sentence) were paired with neutral versions of each sentence and presented dichotically. A control condition was also used, consisting of two identical neutral sentences presented dichotically, with one channel arriving before the other by 7 ms. In support of the RH hypothesis there was a left ear advantage for the perception of sad and happy emotional sentences. However, morphed sentences showed no ear advantage, suggesting that the RH is specialised for the perception of genuine emotions and that a laterality effect may be a useful tool for the detection of fake emotion. Finally, for the control condition we obtained an interaction between the expected emotion and the effect of ear lead. Participants tended to select the ear that received the sentence first, when they expected a 'sad' sentence, but not when they expected a 'happy' sentence. The results are discussed in relation to the different theoretical explanations of valence laterality effects in emotion perception.

The enigma of facial asymmetry: is there a gender-specific pattern of facedness?

Although facial symmetry correlates with facial attractiveness, human faces are often far from symmetrical with one side frequently being larger than the other (Kowner, 1998). Smith (2000) reported that male and female faces were asymmetrical in opposite directions, with males having a larger area on the left side compared to the right side, and females having a larger right side compared to the left side. The present study attempted to replicate and extend this finding. Two databases of facial images from Stirling and St Andrews Universities, consisting of 180 and 122 faces respectively, and a third set of 62 faces collected at Abertay University, were used to examine Smith's findings. Smith's unique method of calculating the size of each hemiface was applied to each set. For the Stirling and St Andrews sets a computer program did this automatically and for the Abertay set it was done manually. No significant overall effect of gender on facial area asymmetry was found. However, the St Andrews sample demonstrated a similar effect to that found by Smith, with females having a significantly larger mean area of right hemiface and males having a larger left hemiface. In addition, for the Abertay faces handedness had a significant effect on facial asymmetry with right-handers having a larger left side of the face. These findings give limited support for Smith's results but also suggest that finding such an asymmetry may depend on some as yet unidentified factors inherent in some methods of image collection.