Annukka K. Lindell

Atypicalities in Cortical Structure, Handedness, and Functional Lateralization for Language in Autism Spectrum Disorders

Language is typically a highly lateralized function, with atypically reduced or reversed lateralization linked to language impairments. Given the diagnostic and prognostic role of impaired language for autism spectrum disorders (ASDs), this paper reviews the growing body of literature that examines patterns of lateralization in individuals with ASDs. Including research from structural and functional imaging paradigms, and behavioral evidence from investigations of handedness, the review confirms that atypical lateralization is common in people with ASDs. The evidence indicates reduced structural asymmetry in fronto-temporal language regions, attenuated functional activation in response to language and pre-linguistic stimuli, and more ambiguous (mixed) hand preferences, in individuals with ASDs. Critically, the evidence emphasizes an intimate relationship between atypical lateralization and language impairment, with more atypical asymmetries linked to more substantive language impairment. Such evidence highlights opportunities for the identification of structural and functional biomarkers of ASDs, affording the potential for earlier diagnosis and intervention implementation.

Thriving and Surviving: Approach and Avoidance Motivation and Lateralization

Two core motivational systems have been conceptualized as underlying emotion and behavior. The approach system drives the organism toward stimuli or events in the environment, and the avoidance system instead deters the organism away from these stimuli or events. This approach—avoidance dichotomy has been central to theories of emotion. Advances in neuroscience complementing well-designed behavioral experiments have begun to elucidate the neural mechanisms underlying approach—avoidance motivation, suggesting that these two systems exist in parallel and are lateralized in the brain. This review explores the notion of approach—avoidance and the cerebral lateralization of these motivational tendencies.

Can science account for taste? Psychological insights into art appreciation

The popular notion that “theres no accounting for taste” reflects a widely held belief that aesthetic preferences are inherently unpredictable. Yet a growing body of research suggests that subjective art appreciation is amenable to objective scientific investigation. This paper reviews the state of the art in the science of art research, examining the extent to which psychological research can account for art appreciation. Taking a two-pronged approach, we first examine how bottom-up variables intrinsic to paintings, including abstraction, form, complexity, and symmetry, reliably influence art appreciation. As the beauty of an artwork can only be appreciated by a beholder, we then examine how top-down influences, such as artwork novelty and viewer expertise, affect the understanding of, and preferences for, paintings. Though the notion that one could ever “fully” explain or predict an aesthetic preference may appear implausibly reductionist, this review demonstrates that scientific methods have shed significant light on a variety of factors that reliably influence art appreciation, paving the way to a greater understanding of the psychology underlying visual art.

Continuities in Emotion Lateralization in Human and Non-Human Primates

Where hemispheric lateralization was once considered an exclusively human trait, it is increasingly recognized that hemispheric asymmetries are evident throughout the animal kingdom. Emotion is a prime example of a lateralized function: given its vital role in promoting adaptive behavior and hence survival, a growing body of research in affective neuroscience is working to illuminate the cortical bases of emotion processing. Presuming that human and non-human primates evolved from a shared ancestor, one would anticipate evidence of organizational continuity in the neural substrate supporting emotion processing. This paper thus reviews research examining the patterns of lateralization for the expression and perception of facial emotion in non-human primates, aiming to determine whether the patterns of hemispheric asymmetry that characterize the human brain are similarly evident in other primate species. As such, this review seeks to enhance understanding of the evolution of hemispheric specialization for emotion, using emotion lateralization in non-human primates as a window through which to view emotion lateralization in humans.

Lateral thinkers are not so laterally minded: Hemispheric asymmetry, interaction, and creativity

The biological basis of creativity remains a topic of contention. A long-held view suggests that whereas the left hemisphere is intelligent and analytic, the right hemisphere is the source of all creativity. Consequently, activating the right hemisphere should enhance creative thinking, prompting a plethora of popular books hawking a right hemisphere solution to topics ranging from drawing, to money management, to sex. More recently, an alternate proposal has suggested that creativity is not a lateralised function; instead, creativity is argued to stem from the interaction and integration of information across both the left and right hemispheres. According to this view, individuals with greater interhemispheric communication and/or less-lateralised brains will evidence enhanced creative ability. This paper reviews the neural basis of creativity to determine whether creativity stems from activation of the right hemisphere, or from the interaction of both hemispheres. The relationship between creativity and psychopathology is also examined, evaluating the evidence for a causal link between disorders such as schizophrenia, hemispheric activation, and enhanced creativity. Although the research reviewed indicates greater right hemisphere activity during creative tasks, the interaction between many varied, often distant, cortical regions across both the left and right hemispheres is also a crucial component of creativity. This interaction facilitates the integration of a variety of separate cognitive abilities, fostering creative thinking. As such, creativity is better conceptualised as a distributed, rather than a purely lateralised, function; more lateral thinkers have less lateralised brains.

The silent social/emotional signals in left and right cheek poses: A literature review

When posing for a painted or photographic portrait, people are more likely to offer their left, rather than right, cheek (e.g., the Mona Lisa). Why? This paper reviews research investigating the left cheek bias, and the reasons underlying this posing asymmetry. Ruling out mechanical and perceptual biases, the paper focuses on the silent emotional and social signals conveyed by left and right cheek poses, demonstrating that people intuitively offer the left cheek to express emotion and perceive left cheek poses as more emotional. Moreover, because the left cheek appears more emotionally expressive, we unconsciously use cheek shown as a cue when presenting or determining academic specialisation, scientific standing, and even political affiliation. The research is consistent in suggesting that something as subtle as a 15° head turn implicitly influences others’ perceptions: if you want to be perceived as open and creative, rather than dry and scientific, it might be time to turn the other cheek.

The perception of positive and negative facial expressions in unilateral brain-damaged patients: A meta-analysis.

How the brain is lateralised for emotion processing remains a key question in contemporary neuropsychological research. The right hemisphere hypothesis asserts that the right hemisphere dominates emotion processing, whereas the valence hypothesis holds that positive emotion is processed in the left hemisphere and negative emotion is controlled by the right hemisphere. A meta-analysis was conducted to assess unilateral brain-damaged individuals’ performance on tasks of facial emotion perception according to valence. A systematic search of the literature identified seven articles that met the conservative selection criteria and could be included in a meta-analysis. A total of 12 meta-analyses of facial expression perception were constructed assessing identification and labelling tasks according to valence and the side of brain damage. The results demonstrated that both left and right hemisphere damage leads to impairments in emotion perception (identification and labelling) irrespective of valence. Importantly, right hemisphere damage prompted more pronounced emotion perception impairment than left hemisphere damage, across valence, suggesting right hemisphere dominance for emotion perception. Furthermore, right hemisphere damage was associated with a larger tendency for impaired perception of negative than positive emotion across identification and labelling tasks. Overall the findings support Adolphs, Jansari, and Tranel (2001) model whereby the right hemisphere preferentially processes negative facial expressions and both hemispheres process positive facial expressions.

Exploring sarcasm detection in amyotrophic lateral sclerosis using ecologically valid measures

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive condition involving degeneration of both upper and lower motor neurons. Recent research suggests that a proportion of persons with ALS show a profile similar to that of frontotemporal dementia (FTD), with this group of ALS patients exhibiting social cognitive deficits. Although social cognitive deficits have been partially explored in ALS, research has yet to investigate such changes using ecologically valid measures. Therefore, this study aimed to further characterize the scope of social cognitive and emotion recognition deficits in non-demented ALS patients using an ecologically valid measure of social cognition. A sample of 35 ALS patients and 30 age-and-education matched controls were assessed using the Addenbrookes Cognitive Examination, the Brixton Spatial Anticipation Test, and The Awareness of Social Inference Test, where participants were required to discriminate between various emotions and decipher socially challenging scenarios enacted in video vignettes. Participants with ALS showed significant difficulties in recognizing both sarcastic and paradoxical sarcastic statements, but not sincere statements, when compared to controls. After controlling for executive difficulties, ALS patients still displayed significant difficulties on tasks that assessed their comprehension of both sarcastic and paradoxical sarcastic statements. The inability to read social cues and make social inferences has the potential to place significant strain on familial/interpersonal relationships in ALS. The findings of this study highlight the importance of employing a broader range of neuropsychological assessment tools to aid in early detection of frontal lobe impairment in non-demented ALS patients.

The influence of autism-like traits on cheek biases for the expression and perception of happiness

People with autism show attenuated cerebral lateralisation for emotion processing. Given growing appreciation of the notion that autism represents a continuum, the present study aimed to determine whether atypical hemispheric lateralisation is evident in people with normal but above average levels of autism-like traits. One hundred and twenty-seven right-handed participants (M=43, F=84) completed the AQ questionnaire (Baron-Cohen, Wheelwright, Skinner, Martin, & Clubley, 2001), and then (a) posed for a photo expressing happiness, and (b) viewed pairs of left and right cheek poses, making a forced-choice decision indicating which image appeared happier (half the images were mirror-reversed to control for perceptual biases). Results indicated that irrespective of AQ status, people were intuitively aware that the left cheek is more emotionally expressive: participants offered the left cheek when posing to appear happy, and perceived left poses as happier than right poses. As the left cheek is predominantly controlled by the right hemisphere, these findings strongly support the right hemisphere hypothesis. The fact that people with normal but above average levels of autism-like traits did not show a reduced leftward bias for either task indicates that the attenuated emotion lateralisation pattern noted in the clinical population does not extend into the normal spectrum. Instead, the results suggest that people with normal but above average levels of AQ traits are as sensitive to the silent social/emotional cues signalled by a left cheek pose as those with lower AQ scores.

Time to turn the other cheek? The influence of left and right poses on perceptions of academic specialisation

The human face expresses emotion asymmetrically. Whereas the left cheek is more emotionally expressive, the right cheek appears more impassive, hence the appropriate cheek to put forward depends on the circumstance. Nicholls, Clode, Wood, and Wood (1999, Proceedings of the Royal Society (Section B), 266, 1517–1522) demonstrated that people posing for family portraits offer the left cheek, whereas those posing as a Royal Society scientist favour the right. Given that the stereotypical representations of members of different academic disciplines differ markedly in their perceived openness and emotionality (e.g., “serious” scientist vs. “creative” writer), we reasoned that people may use cheek as a cue when determining a models area of academic interest. Two hundred and nine participants (M=90, F=119) viewed pairs of left and right cheek poses, and made a forced-choice decision indicating which image depicted a Chemistry, Psychology or English student. Half the images were mirror-reversed to control for perceptual and aesthetic biases. Consistent with prediction, participants were more likely to select left cheek images for English students, and right cheek images for Chemistry students, irrespective of image orientation. The results confirm that determining the best cheek to put forward depends on your academic expertise: an impassive right cheek suggests hard science, whereas an emotive left cheek implies the arts. Psychology produced no left or right bias, consistent with its position as a discipline perpetually straddling the boundary between art and science.