A neuropsychological dimension for anchoring effects

Predicting interactions in handedness research: The role of integrated versus independent dual-processes

Over the past two decades, a new way of looking at handedness has emerged (see Prichard, E., Propper, R. E., & Christman, S. D. (2013). Degree of handedness, but not direction, is a systematic predictor of cognitive performance. Frontiers in Psychology, 4, 1-6), with an emphasis on degree (strong/consistent versus mixed/inconsistent) augmenting the traditional emphasis on direction (left versus right) of handedness. Much of this work has focused on main effects: e.g., inconsistent-handers show higher (or lower) performance than consistent-handers. However, many of these "main effects" are actually nested within higher order interactions: e.g., there are no handedness differences in a baseline/control condition, with handedness differences emerging in an experimental condition. Careful examination, though, of these interactions reveals an intriguing and predictable pattern: for integrated dual processes (e.g., episodic memory encoding versus retrieval), the interactions reflect larger effects in inconsistent-, relative to consistent-, handers. For independent, mutually exclusive dual processes (e.g., approach versus withdrawal), the interactions reflect larger effects in consistent-handers. It is argued that these patterns reflect the relative inability of (i) consistent-handers to integrate dual processes, and (ii) inconsistent-handers to keep independent dual processes separate. We also use this same theory to address higher order interactions involving changes in the experimental context as well as other individual difference factors, and make suggestions for future research.

No Evidence That Lateral Preferences Predict Individual Differences in the Tendency to Update Mental Representations: A Replication-Extension Study

A growing body of evidence suggests that inconsistent hand preference is indicative of an increased disposition to update one’s beliefs upon exposure to novel information. This is attributed to a facilitated exchange of information between the two brain hemispheres among inconsistent handers, compared to consistent handers. Currently available studies provide only indirect evidence for such an effect, were mostly based on small sample sizes, and did not provide measures of effect size. Small sample size is a major factor contributing to low replicability of research findings and false-positive results. We thus attempted to replicate Experiment 1 of Westfall, Corser and Jasper (2014), which appears to be representative of research on degree of handedness and belief updating in terms of the employed methods. We utilized data from a sample more than 10 times the size (N = 1243) of the original study and contrasted the commonly applied median-split technique to classify inconsistent and consistent handers with an empirically grounded classification scheme. Following a replication-extension approach, besides handedness, footedness was also explored. Only one out of 12 chi-squared tests reached significance and supported the original hypothesis that inconsistent handers stay with, or switch more often from, the status quo than consistent handers, depending on the valence of novel information. A small-telescopes analysis suggested that the original study had too low analytic power to detect its reported effect reliably. These results cast doubt on the assumption that inconsistent and consistent-handers differ in the tendency to update mental representations. We discuss the use of the median-split technique in handedness research, available neuroscientific evidence on interhemispheric interaction and inconsistent handedness, and venues of future research.

Individual Differences in Anchoring Effect: Evidence for the Role of Insufficient Adjustment

Although the anchoring effect is one of the most reliable results of experimental psychology, researchers have only recently begun to examine the role of individual differences in susceptibility to this cognitive bias. Yet, first correlational studies yielded inconsistent results, failing to identify any predictors that have a systematic effect on anchored decisions. The present research seeks to remedy methodological shortcomings of foregoing research by employing modified within-subject anchoring procedure. Results confirmed the robustness of phenomenon in extended paradigm and replicated previous findings on anchor's direction and distance as significant experimental factors of the anchoring effect size. Obtained measures of individual differences in susceptibility to anchoring were fairly reliable but shared only small portion of variability with intelligence, cognitive reflection, and basic personality traits. However, in a group of more reflective subjects, substantial negative correlation between intelligence and anchoring was detected. This finding indicates that, at least for some subjects, effortful cognitive process of adjustment plays role in the emergence of the anchoring effect, which is in line with expectations of dual-process theories of human reasoning.

Behavioral genetics of deception detection performance

Purpose

Deception detection is instrumental in business management but professionals differ widely in terms of deception detection performance. The purpose of this paper is to examine the genetic basis of deception detection performance using the classic twin study design and address the research question: how much variance in individual differences in deception detection performance can be accounted for by the variance in genetics vs environmental influences?

Design/methodology/approach

In total, 192 twins, with 65 pairs of monozygotic (identical) twins and 31 pairs of dizygotic (fraternal) twins participated in an experiment. A series of behavioral genetic analyses were performed.

Findings

The variability in deception detection performance was largely determined by differences in shared and non-shared environments.

Research limitations/implications

The subjects were solicited during the Twins Days Festival so the sample selection and data collection were limited to the natural settings in the field. In addition, the risks and rewards associated with deception detection performance in the study are pale in comparison with those in practice.

Practical implications

Deception detection performance may be improved through training programs. Corporations should continue funding training programs for deception detection.

Originality/value

This is the first empirical study that examines the complementary influences of genetics and environment on people’s ability to detect deception.

Individual Differences in Verbal and Spatial Stroop Tasks: Interactive Role of Handedness and Domain

A longstanding debate in psychology concerns the relation between handedness and cognitive functioning. The present study aimed to contribute to this debate by comparing performance of right- and non-right-handers on verbal and spatial Stroop tasks. Previous studies have shown that non-right-handers have better inter-hemispheric interaction and greater access to right hemisphere processes. On this ground, we expected performance of right- and non-right-handers to differ on verbal and spatial Stroop tasks. Specifically, relative to right-handers, non-right-handers should have greater Stroop effect in the color-word Stroop task, for which inter-hemispheric interaction does not seem to be advantageous to performance. By contrast, non-right-handers should be better able to overcome interference in the spatial Stroop task. This is for their preferential access to the right hemisphere dealing with spatial material and their greater inter-hemispheric interaction with the left hemisphere hosting Stroop task processes. Our results confirmed these predictions, showing that handedness and the underlying brain asymmetries may be a useful variable to partly explain individual differences in executive functions.

Neurostructural correlates of consistent and weak handedness

Various cognitive differences have been reported between consistent and weak handers, but little is known about the neurobiological factors that may be associated with this distinction. The current study examined cortical structural lateralization and corpus callosum volume in a large, well-matched sample of young adults (N = 164) to explore potential neurostructural bases for this hand group difference. The groups did not differ in corpus callosum volume. However, at the global hemispheric level, weak handers had reduced or absent asymmetries for grey and white matter volume, cortical surface area, thickness, and local gyrification, relative to consistent handers. Group differences were also observed for some regional hemispheric asymmetries, the most prominent of which was reduced or absent gyrification asymmetry for weak handers in a large region surrounding the central sulcus and extending into parietal association cortex. The findings imply that variations in handedness strength are associated with differences in structural lateralization, not only in somatomotor regions, but also in areas associated with high level cognitive control of action.

Factor analysis of the Edinburgh Handedness Inventory: Inconsistent handedness yields a two-factor solution

While neuropsychology has long focused on direction (left versus right) of handedness, a growing body of evidence indicates that degree (inconsistent versus consistent) of handedness is at least as important. A promising feature of this new emphasis on degree of handedness is its greater concordance with extant genetic models of handedness, which posit a continuum from inconsistent-handedness to consistent right-handedness, not a continuum from left- to right-handedness. Specifically, departures away from consistent-right-handedness are thought to reflect the action of a neutral genetic factor that leaves handedness up to random environmental influences. To test whether handedness in inconsistent-handers reflects the presence of multiple factors (compared to the presence of a single factor only in consistent-right-handers), factor analyses of handedness inventory scores were conducted on data from 987 right-handers, divided into consistent- versus inconsistent-handers. Consistent with predictions, analyses of inconsistent- versus consistent-handers yielded two versus one factor solutions, respectively. Results are discussed in terms of their potential implications for genetic models of handedness and for researchers interested in consistency of handedness as a neuropsychological variable.

Individual differences in information order effects: the importance of right-hemisphere access in belief updating

The order in which information is received alters the evaluation of causal hypotheses. Specifically, research suggests that the last piece of information oftentimes has the greatest impact on the evaluation and that the difference in subjective value between two pieces of information is an important factor influencing the magnitude of this recency effect. The present paper extends this line of work by exploring individual differences in this phenomenon via one's degree of handedness. Two hundred and five participants were given two hypothetical scenarios and related causal hypotheses accompanied by two pieces of additional information and asked to revise their belief in each hypothesis as information accumulated. Results confirmed predictions that 1) inconsistent/mixed-handers (those who use their non-dominant hand for at least some activities) show a larger effect with two pieces of inconsistent weak or strong information, and 2) neither mixed-handers nor consistent/strong-handers (those who use their dominant hand for almost all activities) show an effect with strong and weak pieces of consistent information. Mixed-handers' susceptibility to persuasive arguments and Ramachandran's (1995; Ramachandran and Blakeslee, 1998) belief-updating theory centered around communication between the two halves of the brain and functional access to the right hemisphere are used to account for these data.

Responding to framed health messages: different strokes for different (handedness) folks

Research has shown that strength of handedness - a proxy variable for the degree of interaction between the left and right brain hemispheres - predicts differences in a variety of cognitive domains. The present paper extends this work to message (or goal) framing effects in which persuasive health communications emphasise positive vs. negative outcomes. One hundred fifty-six participants read pamphlets containing statements emphasising either the gains of using or the losses of not using sunscreen. Replicating previous research, non-users of sunscreen were more affected by framed messages than users. However, we found a loss- rather than gain-framed advantage, and mixed (inconsistent)-handers seemed to drive these effects more so than strong (consistent)-handers. These results suggest that a 'one-size-fits-all' approach may be inadequate in crafting effective educational messages about health behaviours, and that theories centring around one's regulatory focus orientation as well as new methods in laterality research may be useful in reaching the widest range of individuals.

Handedness differences in information framing

Previous research has shown that strength of handedness predicts differences in sensory illusions, Stroop interference, episodic memory, and beliefs about body image. Recent evidence also suggests handedness differences in the susceptibility to common decision biases such as anchoring and sunk cost. The present paper extends this line of work to attribute framing effects. Sixty-three undergraduates were asked to advise a friend concerning the use of a safe allergy medication during pregnancy. A third of the participants received negatively-framed information concerning the fetal risk of the drug (1-3% chance of having a malformed child); another third received positively-framed information (97-99% chance of having a normal child); and the final third received no counseling information and served as the control. Results indicated that, as predicted, inconsistent (mixed)-handers were more responsive than consistent (strong)-handers to information changes and readily update their beliefs. Although not significant, the data also suggested that only inconsistent handers were affected by information framing. Theoretical implications as well as ongoing work in holistic versus analytic processing, contextual sensitivity, and brain asymmetry will be discussed.

Individual differences in personality as a function of degree of handedness: consistent-handers are less sensation seeking, more authoritarian, and more sensitive to disgust

Prior research indicates that consistent-handedness is associated with decreased access to right hemisphere processing and consequent decreased cognitive flexibility. Handedness differences on three dimensions of personality related to cognitive flexibility were investigated. Experiment 1 found that consistent-handedness was associated with decreased sensation seeking. Experiment 2 found that consistent-handedness was associated with increased Right Wing Authoritarianism. Experiment 3 found that consistent-handedness was associated with increased sensitivity to disgust. Prior research has shown associations between decreased sensation seeking, increased authoritarianism, and increased disgust sensitivity, and consistent-handedness appears to underlie all of these associations. Personality researchers are encouraged to include handedness as a factor in analyses, as failure to do so can lead to systematic mis-estimation of sex differences due to the over-representation of females among consistent-handers.

Relation between comparative risk, absolute risk, and worry: the role of handedness strength

Research is mixed regarding whether comparative or absolute risk perceptions are most associated with important outcomes (e.g. worry). The current research examined the role of individual differences in organizational brain structure and connectivity-assessed via handedness strength-in moderating these effects. Strong handers and mixed handers made comparative and absolute risk estimates for contracting a sexually transmitted disease or sexually transmitted infection and also indicated their worry. Additionally, participants indicated whether they received testing for sexually transmitted diseases or sexually transmitted infections. For strong handers, absolute risk perceptions were generally more associated with worry and testing behaviors, whereas for mixed handers, comparative risk perceptions were more associated.

Framing effects: the influence of handedness and access to right hemisphere processing

Changing how information is framed, such that the same critical information is cast in a positive or negative light, has a powerful impact on judgements and decision making. Research indicates that the influence of frames may be driven by participants' initial affective response and that the right hemisphere is sensitive to the emotional connotation of stimuli. While previous research tested the effects of hemispheric differences on framing effects by inducing asymmetrical activation, the current study explored how stable brain differences may account for differences in susceptibility to framing effects. Because mixed degree of handedness is associated with increased access to right hemisphere processes, mixed-handed participants were expected to be more susceptible to the effects of framing than strong-handed participants. Participants responded to the Asian disease problem and completed as assessment of handedness. Although mixed- and strong-handed participants were affected differently, the results were not consistent with the hypothesis. Mixed-handed participants conformed to risky choice framing effects when options were framed negatively and showed no effect of the positive frame. Strong-handed participants conformed to positively framed options and showed no effect of the negative frame. Possible explanations are discussed.

Individual Differences in Ambiguous-Figure Perception: Degree of Handedness and Interhemispheric Interaction

Research has shown that persons with strong right-hand preference (ie who report using their dominant hand for all manual activities) display a decreased tendency to update bodily and conceptual representations, possibly arising from decreased interaction between the left and right cerebral hemispheres. Current experiments extend these findings to the domain of perceptual representations. In experiments 1 and 2, strong right-handedness was associated with a decreased ability to update perceptual representations in response to gradually changing perceptual input. In experiment 3, strong right-handedness was associated with lower spontaneous reversal rates during the extended viewing of ambiguous figures, and experiment 4 ruled out an explanation in terms of response bias.

Handedness differences in body image distortion and eating disorder symptomatology

OBJECTIVE

Previous research has shown decreased access in strong right-handers to processes lateralized to the right cerebral hemisphere. The current studies tested the hypothesis that decreased access to right hemisphere processes, as indexed by increasing strength of right-hand preference, is associated with deficits in body image representation.

METHOD

Experiment 1 measured individual's perceived versus actual BMI values. Experiment 2 involved the administration of the Eating Disorders Inventory-2 (EDI-2).

RESULTS

Experiment 1 revealed that strong right-handedness was associated with a larger discrepancy between actual and perceived BMI, relative to mixed-handedness. In Experiment 2, strong-handers scored higher on the EDI-2 than did mixed-handers.

CONCLUSION

The results indicate that strong degrees of handedness are associated with deficits in accurate representation of body image and with increased eating disorder symptomatology in a nonclinical sample. Implications for research into the neural bases of eating disorders are discussed.