The interaction of hemispheric preference, laterality, and sex in the perception of emotional tone and verbal content

Schizotypy and hemisphericity

There is considerable evidence that schizophrenia spectrum disorders are associated with a variety of abnormal asymmetries of brain structure, function, and behavior. Schizotypy is a personality trait dimension extending into the normal range, which at its extreme, is associated with a vulnerability to schizophrenia spectrum disorders. Schizotypy in the normal range is also associated with a variety of neurobiological characteristics associated with schizophrenia spectrum disorders, including abnormal brain and behavioral asymmetries. Previous studies have suggested that normal schizotypy (as well as belief in the paranormal) is associated with an increased reliance on the right hemisphere in a variety of tasks. Hemisphericity is a trait-related characteristic preference for the cognitive mode of one or the other cerebral hemispheres, putatively related to hemispheric activation asymmetry. A sample of 256 undergraduates was administered five schizotypy scales, as well as three hemisphericity measures. Higher schizotypy scores were associated with an increase in right hemisphericity and a decrease in integrated hemisphericity. Although the construct of hemisphericity has been criticized, there is evidence to suggest that questionnaire and eye movement measures of hemisphericity may yet have construct validity, and further research on hemisphericity may be warranted.

Hemisphericity style, sex, and performance on a letter-detection task

Subjects classified by scores on the Preference Questionnaire as preferring either a left- or a right-hemisphericity style were asked to read a one-page passage and to circle each letter t they encountered as they read the passage. There were no statistically significant differences in letter detection between the 58 right- and the 64 left-style scorers. However, contrary to previous findings, the 73 women detected significantly more ts, including unsounded ts, than the 55 men. Our results suggest that hemisphericity style is not an important factor in letter detection.

Hemisphere preference, phobia, and depression

The present study was undertaken in order to examine whether depression and anxiety are related to preference for a right hemisphere mode of thinking. On the basis of a paper-and-pencil test presumably measuring hemisphere preference (Preference Test; Zenhausern, 1978), normal subjects (N = 75) were assigned to a group characterized by a left hemisphere thinking style, a group characterized by a right hemisphere thinking style and a group with mixed tendencies (left and right hemisphere tendencies). Additionally, subjects completed the Fear Questionnaire and the Depression Symptom Inventory. It was found that subjects with a right hemisphere thinking style reported more depressive and fear symptoms than subjects with a left hemisphere thinking style. This finding is in line with theories which assume that the right hemisphere is characterized by a negative, dysphoric emotional tendency.

Hemispheric lateralization of functions related to emotion

We have reviewed the evidence that processes and functions related to perception and expression of emotions are represented asymmetrically in the cerebral hemispheres. The literature describes three possible aspects of emotional lateralization: that emotions are better recognized by the right hemisphere; that control of emotional expression and related behaviors takes place principally in the right hemisphere; and that the right hemisphere is specialized for dealing with negative emotions, while the left is specialized for dealing with positive emotions. Evidence for the three hypotheses derives from methodologically diverse studies in unimpaired, brain-lesioned, and mood-disordered populations. Relatively little of the work has been precisely replicated, and conclusions rest on parallel lines of evidence from diverse sources. The present level of knowledge suggests a model of emotional control based on interactive inhibition between a right negatively biased and left positively biased hemisphere. However, the details of such a model, including the precise conditions under which emotion-related functions are lateralized, and the mechanisms of such lateralization have yet to be elucidated.

Face memory and hemispheric preference: emotionality and extraversion

Subjects made arousing or nonarousing judgments about photographs of strangers, then had an unannounced recognition test over the photographs. Emotional orienting tasks led to better retention than nonemotional tasks. Assuming emotionality is predominantly a right-hemisphere activity, then this result is consistent with other research showing a right-hemisphere advantage in processing faces. This difference was most clear for subjects with a right-hemisphere cognitive style. Extraversion had no effect on face recognition, nor did a subject's cognitive style seem to be associated with extraversion or neuroticism scores.