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Fredric Schiffer, M.D., (781) 237 9620

Can the Different Cerebral Hemispheres Have Distinct Personalities? Evidence and Its Implications for Theory and Treatment of PTSD and Other Disorders

Fredric Schiffer, M.D.

From the Department of Psychiatry, Harvard Medical School at the McLean Hospital, Belmont, Massachusetts, 02478

Address for Reprint Requests: Fredric Schiffer, M.D., McLean Hospital, 115 Mill Street, Belmont, MA 02478

Running Title: Hemispheres and Distinct Personalities

Keywords: Cerebral Hemispheres, Cerebral Dominance, Laterality/physiology, Psychotherapy, Lateral Visual Fields, Personality, Brain/physiology, Corpus Callosum/surgery,

Corresponding Author: Fredric Schiffer, M.D., McLean Hospital, 115 Mill Street, Belmont, MA 02478, (781) 237-9620

Prior Presentation: Much of the material in this paper was presented at a workshop, co-presented with psychologist Thomas Tudor, Ph.D., entitled, "Dual-Brain Psychology Applied to Dissociative Identity Disorder and Posttraumatic Stress Disorder" at the International Society for the Study of Dissociative Disorders, Miami, FL, on November 13, 1999

Journal of Trauma and Dissociation 2000; 1:83-104.


The author presents an evidence based psychological theory which is derived from clinical observations, a review of the literature, especially the split-brain literature, and experimentation with lateral visual field stimulation which has been found to induce changes in patients' cognitive and emotional status thought to be associate with the relative activation of one cerebral hemisphere or the other. The evidence from lateral visual field stimulation suggests that often each hemisphere can have distinct psychological perspectives differing especially in their level of neuroticism with one visual field evoking a more immature perspective than the other. One of the central tenets of the hypothesis is that psychological traumas are associated more with one cerebral hemisphere and than the other, and that the ultimate aim of psychiatric care then becomes the teaching of the mental entity associated with this troubled hemisphere that it is now safer and more valued than it had been at the time of the trauma.


In this paper I will review the ideas and evidence for an hypothesis I have articulated (Schiffer, 1998) that traumatic memories are associated more with one hemisphere (left or right), than the other. This paper does not present new, unpublished data, but rather is the first comprehensive review of my ideas in a journal article and thus presents a more concise and focused presentation of my work than offered previously. I suggest that many patients among a range of psychiatric diagnostic categories, but especially posttraumatic stress disorder and major depression, have two very different, intact ways of seeing themselves and their world, each with congruent cognitions and affects. One view is generally similar to the way the patient saw the world as a distressed child; the second is generally a more mature, more realistic view of the present world. I suggest that each of these views is associated with one hemisphere and that lateralized sensory stimulation, which has been know to affect relative hemispheric activity, can induce shifts in the patientís mental perspective. For instance, I have observed clinically and in the laboratory that lateralized visual stimulation can cause marked changes in a patientís disposition from immature to mature or vice a versa. This theory of dual mental states may be a guide to understanding patients and helping them overcome their traumas. In this paper, I describe how I came to these hypotheses through clinical observation, literature review, experimentation, and reflection. Experiments and anecdotal clinical applications of lateral visual field stimulation support the psychological ideas about the existence and relationships of the two mental aspects I have observed in many patients. Further, my anecdotal evidence indicates that lateralized sensory stimulation can be used as an effective adjunct to psychotherapy, and I will describe the practical application of this theory to psychotherapy as well as the enhancement of therapy through the use of lateralized sensory stimulation.

Origins of the Hypothesis

During my residency in psychiatry in the early 1970's, I began to feel that the majority of my patients had two distinct aspects to their personalities, one that was more mature and one that was more troubled. The troubled aspect seemed to relate not so much to Freud's tripartite model (Freud, 1963) as to childhood traumas. Interpretations of the patient's difficulties usually evolved from an attempt to empathetically appreciate how the patient may have felt during a past traumatic period, and that perspective often led to a clearer dynamic understanding of the patient's symptoms. Serious psychological theoreticians did not support the idea that the unconscious resembled an intact, though trouble, inner child (Munroe, 1955). The popular concept of the "inner child" did not emerge until the mid 1980"s, and was never fully developed into a sophisticated, complex hypothesis. More recent theoreticians have begun to conceptualize the unconscious as a more intact, more developed mind (Horowitz, 1991; Luborsky & Crits-Christoph, 1990; Weiss, 1993).

In the late 1980's, I re-read works emanating from the split-brain studies. These famous studies, for which Roger Sperry won the Nobel Prize in 1983, were performed on patients who had had intractable epilepsy treated by a callosotomy, a section of the corpus callosum (Bogen & Vogel, 1962). I appreciated only then the true significance of this important body of work: that there was little evidence that the left brain was logical and the right poetic, but there was overwhelming evidence that these patients manifest two autonomous minds. In a typical experiment (Sperry, 1968; Springer & Deutsch, 1998), Sperry and his associates would briefly flash a picture of an object to one side of the patient while he or she kept their eyes fixed on a central point. As diagramed in figure 1, the neural connections between the eyes and the brain are such that an image presented to one side of a patient will go first to the opposite hemisphere. In intact individuals, such visual input can be shared with the opposite hemisphere via the corpus callosum, but in the split-brain patients, the information remains in one hemisphere. The presentation of a brief exposure of the picture was to prevent the patient's scanning it and exposing it to the other hemisphere.

As shown in figure 1, an image presented to the left side of a patient's head will be seen by the patient in his or her left visual field. The term visual field refers to that part of the environment that the patient sees, and is divided into left and right halves (or lateral visual fields), relative to the patient. As shown also in figure 1, an image presented to the left side of the patient (to his or her left visual field) is inverted by the lens of the eye so that it stikes the retina on side opposite to the lateral visual field. The medial half of the retina, which repesents about 60% of the retina, crosses over via the optic nerve to the opposite hemisphere. Thus, an image presented to the left side or left visual field of the patient will stike the medial half of the left retina and cross over to the right hemisphere. If the right eye were unobstructed, this same image would fall on the right half (lateral aspect) of the right retina and also travel to the right hemisphere. Thus, whether presented to one eye or both eyes, an image presented to the left visual field will be seen first by the right hemisphere, and an image presented to the right visual field will be seen first by the left hemisphere. In the following presentation, when discussing visual stimulation, I will do so in reference to the left or right lateral visual field and not to the side of retinal stimulation.

In split-brain patients only the left hemisphere possesses the ability to speak. The right hemisphere is mute. When Sperry flashed a picture to the patients' right visual field (to the left brain), they were able verbally to identify immediately the object in the picture, as would any healthy, intact people. However, when the picture was flashed to the the patients' left visual field (to the right brain), the split-brain patients repeatedly said they could not see it. Sperry then asked the patients to reach behind a curtain with their left hand (connected to the right brain to which the picture was flashed), handle objects in a box, and pull out the one matching the picture. All of the split-brain patients so tested were able to perform this task with ease. Thus, when a picture of perhaps a pipe was flashed to their left visual field (to the right brain), they said (the left brain speaking) that they could not see it. But, with their left hand (connected to their right brain), all of the patients could easily reach behind the screen and select the correct item. Thus, the mute right hemisphere demonstrated that it could understand the English language well enough to comprehend what was asked of it. Further, it was capable also of easily carrying out the task of selecting the correct item, and it was capable of doing so without the awareness or assistance of the left hemisphere.

In later experiments (Sperry, Zaidel, & Zaidel, 1979), photographs of people were shown to only one hemisphere depending on which lateral visual field was presented with the picture. If shown to the right visual field (left brain), the patient could say who was in the picture and could verbally express his opinion of the person as would a healthy, intact person. If the experimenters showed the picture to the left visual field, it was seen by only the right hemisphere, and the "speaking" left brain would again say that it was unable to see the photograph.

When the photograph was shown to the left visual field (right brain), the experimenters asked the patients to use their left hands to make a thumb signal to express their opinions of the person in the picture (which the left brain reportedly did not see). In one experiment (Sperry et al., 1979), the first picture was given thumbs up, the second thumbs down, and the third thumbs horizontal. The first picture was of Johnny Carson, the second, Adolph Hitler, and the third, Richard Nixon in the early 70's. Thus, the disconnected right hemisphere was able to have and express political opinions.

Most studies of the split-brain patients (Kolb & Whishaw, 1990; Springer & Deutsch, 1998), with a few exceptions (Gazzaniga & LeDoux, 1978; Hoppe, 1977; TenHouten, Hoppe, Bogen, & Walter, 1986), focused on cognitive tasks such as verbal or spatial abilities rather than on the psychological properties of the hemispheres. In collaboration with Sperry's successors, Joseph Bogen and Eran Zaidel, I performed a study in two split-brain patients in which a series of questions of a psychological nature were posed to each hemisphere (Schiffer, Zaidel, Bogen, & Chasan-Taber, 1998). Each hemisphere responded independently with its contralateral hand by touching one of five pegs in front of each hand. The pegs represented "none," "mild," "moderate," "quite-a-bit," or "extreme," and by touching a given peg each hand indicated the responses of the contralateral hemisphere. To verify that the responses were meaningful and coming from the contralateral hemispheres, we included questions with obvious answers such as "Do you like taxes?" In one patient we were able to simultaneously ask different questions of the two hemispheres by verbally asking the beginning of a question such as "How much do you feel: ______?" and having the question completed by flashing different words (such as "confident" and "sad") to the two lateral visual fields.

During a brief psychiatric interview, one of the two split-brain patients told me that he had been bullied as a child. He told me further that he was not at all bothered by those incidents because they had occurred about 30 years earlier. When he was tested, I asked 35 questions of a general psychological nature such as "How anxious do you feel?" or "How confident do you feel?" I also asked 14 questions about the bullies such as "How angry do you feel about the bullies?" or "How much does the bullying still bother you?" On the general questions, both hands generally responded similarly, but on the questions about the bullying there was a large discrepancy between the responses given by his two hands. His right hand, answering for his left hemisphere, as he had already told me, indicated that he was not bothered by the bullies. But his left hand consistently indicated that he was still very disturbed by the bullying. We interpreted this to mean that his right brain was still quite upset by the bullying even though his left was not.

The split-brain studies demonstrated that the two hemispheres in such patients manifested separate, autonomous centers of mental functioning or minds (Bogen, 1969; Sperry, 1968). Studies of the psychological properties of the two minds indicated that they had different psychological properties (Hoppe, 1977; Schiffer et al., 1998; TenHouten et al., 1986), and these findings led to speculations about the role of the hemispheres in the psychology of intact individuals (Galin, 1974; Joseph, 1990; Schiffer, 1996).

Evidence for Two Distinct Psychological Perspectives in Intact Individuals

Philosopher Jennifer Radden (Radden, 1996) has argued that some patients may manifest two distinct selves. She defines as a self as "an embodied repository of integrated psychological states," each having separate "beliefs, values, goals, desires, and responses." As examples of individuals with such marked persistent alterations in mental state, she offers patients suffering alternations between manic states with normal states of mind or individuals suffering dissociative disorders with alternating changes in personality. Still, the idea of alternating selves in one person not only in intact individuals, but also in split-brain patients, has been controversial (Dennett, 1989).

In Sperry's (Sperry, 1990) and others' opinions (Joseph, 1990; Schiffer, 1998) the evidence from split-brain patients as presented above clearly demonstrates that such patients manifest two distinct centers of mental activity, one associated with each hemisphere, each capable of separate beliefs, values, goals, desires, and responses. Bogen (Bogen, 1969; Bogen, 1990) and others (Pucetti, 1981; Schiffer, 1998) have suggested that intact individuals may also have two selves. For instance, as reviewed by Schiffer (Schiffer, 1996; Schiffer, 1998), Wada studies, in which one hemisphere at a time is anesthetized with a short acting barbiturate, have demonstrated in a few intact patients compelling evidence of two autonomous minds in one individual (Ahern et al., 1993; Risse & Gazzaniga, 1978). These Wada studies suggest the capacity of each hemisphere in intact individuals to support separate autonomous minds.

A large literature has suggested that hemispheric differences might be important to affect processing (Davidson, 1995; Ross, Homan, & Buck, 1994). Studies in this area, relying on averaged data, have generally shown that the right hemisphere is somewhat more sensitive to the detection of affect in general and that it may be more associated with the experience and expression of negative affect. These studies have generally not been supported by functional imaging studies (Lane, Reiman, Ahern, Schwartz, & Davidson, 1997; Teasdale et al., 1999), and small differences in affect processing do not offer evidence for two selves in one individual.

Lateralized Visual Field Stimulation and the Contralateral Hemisphere

As discussed above and illustrated in figure 1, it has long been known that each lateral visual field sends input directly to the contralateral hemisphere. To study hemispheric differences, many scientists have used this fact and conducted and published hundreds of divided field studies in normal individuals (Young, 1982; Zaidel & Rayman, 1994). They have consistently found that when verbal material is presented to the right visual field (to the left brain), it is processed more efficiently than when it is presented to the left visual field. Lempert and Kinsbourne (Lempert & Kinsbourne, 1982) found that when college students were asked to turn their heads and look to their right side, they could do a verbal task better than when the looked and turned to the left. Kinsbourne suggested looking to one side might tend to activate the contralateral hemisphere and inhibit the other (Kinsbourne, 1983).

More recently, Levick and associates (Levick et al., 1993), reported a series of experiments using contact lenses which allowed vision out of only one side of each lens in 23 male college students. The experimenters found that on average the students could perform a verbal task better when the contact lenses were rotate to the right and that they could perform a spatial task better when the lenses where rotated to the left. In a subgroup of 8 of these students, Levick recorded EEG's from the frontal and temporal areas. He found that when the contact lenses were rotated to one side the EEG activity showed a significant decrease in the theta spectrum in the contralateral hemisphere, suggesting an increase in that hemisphere's relative lateral activity. Significant shifts were not found in the alpha EEG spectrum.

Dimond (Dimond, Farrington, & Johnson, 1976) used a contact lens which was occluded on one side, and by closing the opposite eye and rotating the lens, he could have subjects view movies with either half of the retina, each connected to a different hemisphere. Dimond found that subjects tended to report more emotion when the right hemisphere was the first to receive the images.

Wittling and his associates (Wittling, 1995; Wittling & Pflüger, 1990; Wittling & Roschmann, 1993; Wittling & Schweiger, 1993) have published several studies in which they purport to show video tapes to one hemisphere or the other using a complex system which tracked the subjects' eye movements and masked a computer screen so that the subjects essentially saw the video with only their left or their right lateral visual field. The subjects' blood pressure, heart rate, affect, and cortisol levels have been shown to vary depending on to which visual field the experimenters choose to show the video. For instance in a healthy population, upsetting videos aroused more affect when shown to the left visual field which is thought to favor the arousal of the right hemisphere (Wittling & Roschmann, 1993). In contrast, a population of patients with psychosomatic problems showed more negative affect, on average, when the upsetting videos were sent to the right visual field, thought to favor the relative arousal of the left hemisphere (Wittling & Schweiger, 1993).

Greenberg and his colleagues (Greenberg et al., 1981) used PET scans to image brain glucose activity in healthy males exposed to unilateral sensory stimuli. Unilateral visual hemifield stimulation activated, relatively, the contralateral striate cortex. Unilateral touch and unilateral sound each activated, relatively, the contralateral hemisphere in the area of the primary sensory cortex for each modality. In a more recent study using fMRI, Gandhi and associates (Gandhi, Heeger, & Boynton, 1999) found that attention to a lateral visual field activated relatively the contralateral hemisphere.

Levick's, Wittling's, Greenberg's, and Gandhi's findings are consistent with Kinsbourne's hypothesis that unilateral sensory stimulation may tend to activate the contralateral hemisphere in spite of the fact that the corpus callosum transfers information between the hemispheres and in spite of the fact that, in the case of the visual and auditory stimulation, the initial stimulus does go to both hemispheres, although predominately to the contralateral hemisphere.

Emotional and Cognitive Changes Induced by lateralized Sensory Stimulation

Schiff (Schiff, Guirguis, Kenwood, & Herman, 1998; Schiff & Lamon, 1994) and associates have reported changes in affect and perception following unilateral muscle contractions of the face or hand. They found that on average left sided contractions were associated with more negative affects and perceptions, and attributed their findings to the effects of activation of the cerebral hemisphere contralateral to the muscle contractions.

I reported (Schiffer, 1997) that limiting vision to the left or right lateral visual field (using taped safety goggles allowing vision out of only the lateral third of one eye as shown in figure 2A) and comparing anxiety levels from one side to the other revealed that 42 (60 percent) of 70 psychotherapy patients experienced a least a 20% difference in their anxiety levels between sides and that 38% of these 42 patients reported at least a 40% difference. The side on which the great anxiety was experienced varied between diagnostic groups. Among 21 patients with major depression, 71 percent had at least a 20 percent difference in anxiety levels between sides and of these 73 percent felt more anxiety when looking to the left visual field (right brain). Among 18 patients with posttraumatic stress disorder, 78 percent reported at least a 20 percent difference between the two lateral visual fields, but the majority, 71 percent, experienced more anxiety when looking to the right visual field (left brain).

My findings in the patients with posttraumatic stress disorder forced me to reevaluate an hypothesis I expressed (Schiffer, 1996) based on my review of the literature and consistent with the predominate view in the field (Davidson, 1995) that the right hemisphere is associated with negative affect. On reconsideration (Schiffer, 1998), I realized that most of the studies that suggested a relationship between the right hemisphere and negative affect were base on averaged data which taken alone can give an inaccurate impression that the average represents all individuals. Men are taller than women on average, but the inference that all men are taller than all women would obviously be false. Further, on looking more closely at the literature, a number of functional imaging studies (Lane et al., 1997; Rauch & Shin, 1997) have not found a relationship between negative affect and the right hemisphere and other studies have reported an association between negative affect and the left hemisphere in some populations (Wittling & Schweiger, 1993), particularly those with trauma patients (Bremner et al., 1997; Gerhards, Yehuda, Shoham, & Hellhammer, 1997; Teicher et al., 1997; Teicher, Ito, Glod, Schiffer, & Gelbard, 1996).

In anecdotal observations (Schiffer, 1998), I reported that many patients who had intense affective responses to lateral visual field stimulation reported not only differences in anxiety, but also often reported dramatic cognitive changes congruent with the affect changes. Repeatedly, I observed, in responsive patients that they reported very different perceptions of their sense of their inherent value and of their sense of their safety depending on which lateral visual field they were looking from. Many of these anecdotal reports include transcripts (Schiffer, 1998) from sessions with patients while they wore different lateralized goggles, and they are notable for the psychodynamically relevant effects which have frequently been observed. For example, typical very responsive patients might report that they believe they are stupid and lazy on one side and within seconds of changing glasses will feel that they are ambitious and intelligent. Their opinion on the negative side is consistent with what they were told as children by abusive parents. Some patients have reported feeling that I was expressing negative affect towards them on one side but not the other. In these cases, I have asked the patient to look at a photograph of a famous person, and he or she felt the expression in the photograph changed depending on from which lateral field it was view. The side which saw the photograph as troubling was the same which saw me in that manner.

As an actual example, among many presented elsewhere (Schiffer, 1998), I offer the transcript of an audio tape recorded during a session with a 43 year old male who had been the victim of severe psychological abuse. This man was a former patient of mine who completed his treatment several years earlier and who came to my office at my request to try the lateralized taped goggles. The patient had suffered a depression complicated by substance abuse related to his father's constant derision beginning in the patient's childhood. We felt he had a good result from his treatment, and he reported that he had been doing well over the years since we terminated.

After he settled into the meeting, as a baseline I asked him to rate his immediate level of anxiety on a scale including none, mind, moderate, quit a bit, or extreme, and he reported a mild level. A few seconds after his putting on the right visual field goggles, I asked him how he was feeling and he reported that his anxiety had increase to a moderate level. I asked him to elaborate.

"Anxious, cause I feel I can't see what might be comin' at me from the other side."

"Is this a new feeling or a familiar feeling?"

"Sort of familiar because I'm in business and you never know what's about to happen. Definitely unknown."

"Would you try the other goggles? . . . How much anxiety are you feeling looking out the left side [right brain]?"

"I think less. . . . Mild."

"Can you describe the difference between how you feel on this side versus the other side?"

"I'm more relaxed on this side. The other side I was a little more uptight." . . . .

"Let's put the other pair back on? . . . How do you feel?"

"Same as before. Not as comfortable as the other side. . . .Not a good sign here. I'm just thinking about things I did in the past and everything about me then. I don't really think about anybody but myself and the abuse, some of the things I've been through in life. This is not what I want to remember. Not good. Can I take them off now?"

"Now I just want to ask you one more question. Can you relate these uncomfortable feelings to your father?"

"I don't know. I was never comfortable around my father. With these glasses on it's sort of like dealing with him again because it's always the unknown, and it's always a pressure and a problem. . . . Yeah, you feel the unknown, you have the tension. . . ."

"Let's put the other glasses on [right brain]."

"More relaxed. More focused. Clearer."

"Now if you think of your father on this side."

"I can deal with him on this side. I know how to handle him now, and I don't think he'd get me upset, and I wouldn't do the counterproductive things if I looked at him out of this side all the time. I'd feel more pity for him and for the relationship, and I don't think I'd want to abuse myself by using drugs."

"What would someone have to do to you to get you to use drugs, feeling the way you do on this side?"

"I don't think it's an option on this side."

"Would they have to have a gun on something?"

"Oh, yeah, they'd have to do some extreme things."

"On the other side?"

"Yeah, I could see myself doin' it on the other side."

These observations are contrary to ordinary experience, and their nature has needed to be explored further. Two placebo controlled studies have been published to date (Schiffer, 1997; Schiffer, Anderson, & Teicher, 1999). In both studies we compared the absolute differences in anxiety levels between safety goggles taped to allow vision predominately (but not exclusively) out of one lateral visual field. See figure 2A. As a control (see figure 2B), we used similar goggles taped to allow vision out of one entire eye which should activate both hemisphere although unequally since about 60 percent on each retina sends its output to the opposite hemisphere. The control, monocular goggles had tape on the bottom of the lens on the open side to make them appear more complex so that they would elicit more placebo effects. In the first placebo controlled trial, 40 psychotherapy patients were given in random order each of the four goggles. A second placebo controlled trial was done in 15 college students. In both trials, the absolute differences in anxiety between the two experimental goggles was significantly greater than that between the two control goggles. Neither study was able to use blind observers, but the second study recorded EEG's and bilateral ear temperatures in addition to the affect measurements. In these 15 college students we did a spectral analysis of the absolute power of the EEG in the frontal and temporal leads and found that in all subjects there was a shift in the expected direction in the laterality index for the theta band between the left and right experimental goggles. This difference was highly significant. For the monocular goggles these differences were not consistent and did not approach significance. We did not find significant differences in the alpha band, and interestingly, Levick (Levick et al., 1993) and his associates had a similar finding of significant shifts in theta but not alpha EEG in their study of college students using contact lenses to limit vision to one then the other lateral visual field. In our study, we found also significant changes in lateral ear temperature differences in the anticipated directions with the experimental but not monocular goggles. The ear temperature differences correlated highly with the EEG changes.

My colleagues and I are attempting to study these phenomena further. Grant applications are in submission for fMRI studies with the lateralized glasses, for other physiological studies of the acute effects of the glasses, and for randomized, placebo controlled, blind, long term outcomes of various patient populations using the lateralized glasses. One study using lateralized goggles to replicate my findings of acute affect changes and to use them to predict the clinical outcomes from a two week course of transcranial magnetic stimulation to stimulate the left frontal cortex in 37 severely depressed patients is in submission. Like Schiff (Schiff et al., 1998), I have evidence, although anecdotal and unpublished, that lateral stimulation, via other sensory or motor activation, can induce changes in psychological state similar to (but perhaps less intense) those reported here; and I hope that further study will evaluate this impression.

Theoretical Implications

The observations of marked changes in cognition and affect in response to lateral visual stimulation, which has been shown to shift hemispheric dominance, has led me to speculate that the induced changes in mental status are related to the induced changes in relative hemispheric activation. A common observation in responsive patients is that lateral visual stimulation will on one side evoke a relatively mature psychological perspective and that stimulation of the opposite side will evoke a relatively immature perspective related to traumatic experiences the patients had in their childhoods. In light of the split-brain studies which have demonstrated the ability of each isolated hemisphere to be capable of a high level of independent mention, and in light of my finding of a high level of psychological change induced by lateral field stimulation, I speculate that the lateral visual stimulation alters hemispheric dominance which leads to a change of psychological status. This line of reasoning has led me to consider that my early clinical observations (that patients very often had a fairly intact, internally consistent immature psychological aspect as well as a more mature contrary aspect) may relate to my observations following lateral visual field stimulation, and that each hemisphere may be associated with psychological traits differing in their level of psychological maturity and in their associated perspective on past traumas.

Thus, I have conceptualized the human mind as often having a major division between two intact perspectives one more mature and realistic and one more childlike with perspectives related to past traumas, holding on to misperceptions that the world remains dangerous and rejecting as it once was. The relationships between these two mental aspects can be varied and complex. At times one might dominate or sabotage the other, or they might cooperate. When the immature aspect dominates, the person might be seen clinically as "regressed." If the mature side suppressed the troubled side, and the person might be seen as "repressed." At times the immature side may act covertly as an "unconscious mind" inducing "neurotic behaviors" such as airplane phobias which are experienced but not easily understood by the person. In this view, an "interpretation" is the decipherment of the thoughts and feelings of a troubled, less mature mind working covertly beyond the awareness of the consciousness of the more mature side. At times when the immature side is the dominant, conscious mind the patient may be seen as having a "personality disorder" and as "acting out." "Transference" in my view is the relationship between the immature side of a patient's personality and the therapist.

In essence, my hypothesis is trauma based. I suggest that the immature side maintains a perspective very similar to one consistent with that which a child in a troubled circumstance might be expected to experience. I can offer no compelling explanations on why one hemisphere would be more associated with past traumatic experiences. Patients with posttraumatic stress disorder in my practice have been the most responsive group to lateral visual stimulation, but other patient groups have also been responsive. I believe that the great majority of psychological problems are due to traumas which can range from a relative neglect to extremes of abuse, and so I would expect this trauma based hypothesis to relate to a very wide range of psychological problems. Certainly profound abuse will have different consequences from less severe traumas, but my findings suggest that all types of abuse could have some tendency to relate to one hemispheres more than the other, at least in the large number of patients who have typical, intense responses to lateralized stimulation.

Clinical Implications

There are two aspects to the ideas I am presenting and both have clinical relevance. The first is the general psychological theory that most people have a mature and an immature part to their personalities. This hypothesis has usefulness in our attempts to understand human behavior and to assist people with their psychological problems. This conceptualization of the mind allows the theoretical insights described in the previous section. It formulates psychopathology as usually coming from an immature aspect which still believes it is in the midst of a traumatic experience. Psychotherapy is then conceptualized as the teaching of this troubled, immature aspect, that it is in fact safer and more valued than it has realized. Usually the troubled part of the personality does not realized that a new, more mature, more realistic part of the mind has come into existence since childhood. The therapist can help the patient find and use this more mature part of the patient's personality to help the troubled part. Regarding the troubled aspect as a well developed mental entity with its own thoughts and feelings, allows the patient and therapist to more concretely and directly address, communicate with, and then teach this more childlike aspect. As I describe at greater length elsewhere (Schiffer, 1998), I often talk directly to the immature aspect of the patient, and this not infrequently evokes an almost immediate improvement in the patient's mental state. This improvement, though usually temporary, may be the inarticulate response of the immature aspect of the personality to my statements. The resolution of clinical problems can be achieved when the therapist and patient's mature side successfully teach the immature part that it is now in fact safer and more valued than it had believed based on past traumatic experiences. The establishment of a trusting, enduring, positive relationship between the therapist along with the mature aspect of the patient and the immature aspect is necessary for this teaching to take place.

The dramatic psychological effects of lateralized stimulation are the second aspect of my ideas to have clinical relevance. First, these effects lend support for the hypothesis that the immature aspect of a person is a well developed cognitive and emotional entity with a perspective on itself and the world which is based largely on past traumatic experiences. This assertion is based on the fact that lateralized stimulation often evokes on one side a consistent perception in patients that they are deficient in value and safety. This view is consistent with their symptoms and with their past experiences.

In addition to supporting the psychological hypothesis, the findings from lateralized stimulation, in my anecdotal clinical experience, have had clinical value as an adjunct to psychotherapy. In patients who are responsive to the lateralized stimulation, I have found that allowing them to dramatically alter their perceptions of themselves and their world within seconds of switching the side of lateral stimulation is often remarkably helpful. First, such experiences force the patients to challenge their entrenched negative perceptions, for if perceptions can be so easily altered, their veracity requires reconsideration. Further, stimulating the positive aspect of the patients will offer them a direct experience of their positive value and safety. If I were to tell a person that he was valued and safe, I would have not have the compelling power of the patients' seeing this for themselves. Lateralized stimulation appears to be a powerful adjunct for teaching the troubled aspect of the patient that they are truly valuable and safe.

My anecdotal observations lead me to believe that as the troubled hemisphere improves it forms a better relationship with the other side. In this sense the hemispheres become more harmonious or balanced, but such improvement is possible only after the troubled side becomes healthy enough to begin to engage in that relationship. This model resembles the relationship between a traumatized child and a therapist or a healthy parent.

I have experienced patients who were able to access negative feelings only when they wore the lateralized glasses which evoked the negative side and this use has been helpful in responsive patients who tend to repress their affect. With other patients I have used the goggles to help them discuss traumatic events which would be too distressing to talk about without the aid of the comforting glasses. A number of patients have used the taped goggles at home usually as method for inducing a state of comfort and calmness, in a manner resembling the way some people use the practice of meditation.

Some of clinicians have reported to me that they feel uncomfortable trying new techniques and have requested that I present a hands on workshop to assist them. I am of the opinion that these techniques are not so complex and are simply an extension of traditional dynamic psychotherapy. To date I have not had any adverse effects after using the goggles many hundreds of times in about two hundred patients. My suggestion to clinicians who wish to become more familiar with using lateral visual field stimulation in a clinical setting is that they go through the following exercise with themselves: 1. immediately after a forty-five second baseline condition, measure your level of anxiety from "none," "mild," "moderate," "quite-a-bit," or "extreme." Then take a standard letter sized envelope and hold it so that you cover one eye and half of the other. Wait forty-five seconds and repeat the measure of your anxiety. Then move the envelope so that you can see only out of the lateral half of your other eye, and repeat the anxiety measurement. It is important to wait the amount of time and to actually make the anxiety measurements. If you notice a difference in how you score, then repeat the trials, but in each condition ask yourself how you feel about yourself, your work, and/or your partner. This simple procedure is a basic one I currently use with patients. With patients who feel differently on the different sides, I ask them to discuss the differences with an ultimate aim of trying to teach their troubled sides. Not infrequently, after what feels to me as a very productive session, the patient will return the following week and seem uninterested in what we accomplished. Over weeks or months, however, in successful cases the troubled side becomes less troubled as it actually learns that it is safer and more valued than it was taught through earlier experiences. As the troubled side learns, the patient's symptoms abate. Although I have used these techniques with patients with a range of different diagnoses, I have observed anecdotally that those with posttraumatic stress disorder as a group appear to be the most responsive to both the acute and the long term effects of this treatment.


Figure 1.

A schematic repesentation of the connections between the eyes and the brain. An object (the airplane) appears in the left visual field. The image of the plane goes through the lens of the left (unblocked) eye and strikes the right side of the retina of that eye. The retina in each eye is divided into a lateral and a medial aspect. The lateral aspect of each retina is connected to the ipsilateral hemisphere and the medial aspect to the contralateral. (1) points to the medial retina of the left eye which is connected by the optic nerve (2), through the optic chiasm (3) to the contralateral (right) hemisphere (4). Via the corpus callosum (5) the image can then be transferred to the other hemisphere. In split-brain patients, who have this connection severed, the image stays on one side.

Figure 2.

A. Experimental goggle allowing vision primarily out of the right visual field

B. Left sided monocular (placebo control) goggle with tape on the bottom of the left lens to give the goggle a more complex appearance.


Ahern, G., Herring, A., Trackenberg, J., Seeger, J., Oommen, K., Labiner, D., & Weinand, M. (1993). The association of multiple personality and temporolimbic Epilepsy: Intracarotid amobarbital test observations. Arch Neurol, 50, 1020-1025.

Bogen, J. (1969). The other side of the brain: II. an appositional mind. Bull Los Angeles Neurol Soc, 34, 135-162.

Bogen, J. (1990). Partial hemispheric independence with the neocommissures intact. In C. Trevarthen (Ed.) (Vol. Brain Circuits and Functions of the Mind: Essays in Honor of Roger W. Sperry, ). Cambridge: Cambridge University Press.

Bogen, J., & Vogel, P. (1962). Cerebral commissurotomy in Man. Bull Los Angeles Neurol Soc, 29, 169-172.

Bremner, J., Randall, P., Vermetten, E., Staib, L., Bronen, R., Mazure, C., Capelli, S., McCarthy, G., Innis, R., & Charney, D. (1997). MRI-based measurement of hippocampal volume in posttraumatic stress disorder related to childhood physical and sexual abuse: A preliminary report. Biological Psychiatry, 41, 23-32.

Davidson, R. (1995). Cerebral asymmetry, emotion, and affective style. In R. Davidson & K. Hugdahl (Eds.), Brain Asymmetry . Cambridge: MIT Press.

Dennett, D. (1989). The origins of selves. Cogito, 2, 163-173.

Dimond, S., Farrington, L., & Johnson, P. (1976). Differing emotional response from right and left hemispheres. Nature, 261, 690-692.

Freud, S. (1963). The Ego and The Id (1923) (Vol. 22). London: Hogarth Press.

Galin, D. (1974). Implications for psychiatry of left and right cerebral specialization. Arch Gen Psychiatry, 31, 572-583.

Gandhi, S., Heeger, D., & Boynton, G. (1999). Spatial attention affects brain activity in human primary visual cortex. Proc Natl Acad Sci, 96(6), 3314-3319.

Gazzaniga, M., & LeDoux, J. (1978). The Integrated Mind. New York: Plenum.

Gerhards, F., Yehuda, R., Shoham, M., & Hellhammer, D. (1997). Abnormal cerebral laterality in posttraumatic stress disorder. Annals of the New York Academy of Sciences, 821, 482-485.

Greenberg, J., Reivich, M., Alavi, A., Hand, P., Rosenquist, A., Rintelmann, W., Stein, A., Tusa, R., Dann, R., Christman, D., Fowler, J., MacGregor, B., & Wolf, A. (1981). Metabolic mapping of functional activity in human subjects with the [18F]fluorodeoxyglucose technique. Science, 212(4495), 678-680.

Hoppe, K. (1977). Split brains and psychoanalysis. Psychoanal Quart, 46, 220-244.

Horowitz, M. (1991). Person schemas. In M. Horowitz (Ed.), Person Schemas and Maladaptive

Interpersonal Patterns . Chicago: Univ of Chicago Press.

Joseph, R. (1990). Neuropsychology, Neuropsychiatry, and Behavioral Neurology. New York: Plenum Press.

Kinsbourne, M. (1983). Lateral input may shift activation balance in the integrated brain. American Psychologist, 38, 228-229.

Kolb, B., & Whishaw, I. (1990). Fundamentals of Human Neuropsychology. New York: WH Freeman.

Lane, R., Reiman, E., Ahern, G., Schwartz, G., & Davidson, R. (1997). Neuroanatomical correlates of happiness, sadness, and disgust. Am J Psychiatry, 154, 926-933.

Lempert, H., & Kinsbourne, M. (1982). Effects of laterality of orientation on verbal memory. Neuropsychologia, 20, 211-214.

Levick, S., Lorig, T., Welxler, B., Gur, R., Gur, R., & Schwartz, G. (1993). Asymmetrical visual deprivation: a technique to differentially influence lateral hemispheric function. Perceptual and Motor Skills, 76, 1363-1382.

Luborsky, L., & Crits-Christoph, P. (1990). Understanding Transference. New York: Basic Books.

Munroe, R. (1955). Schools of Psychoanalytic Thought: An Exposition, Critique, and Attempt at Integration. New York: Henry Holt and Company.

Pucetti, R. (1981). The case for mental duality: evidence from split-brain data and other considerations. The Behavioral and Brain Sciences, 4, 93-123.

Radden, J. (1996). Divided Minds and Successive Selves: Ethical Issues in Disorders of Identity and Personality. Cambridge: The MIT Press.

Rauch, R., & Shin, L. (1997). Functional neuroimaging studies in posttraumatic stress disorder. Annals of the New York Academy of Sciences, 821, 83-98.

Risse, G., & Gazzaniga, M. (1978). Well-kept secrets of the right hemisphere: A carotid amytal study of restricted memory transfer. Neurology, 28, 950-953.

Ross, E., Homan, R., & Buck, R. (1994). Differential hemispheric lateralization of primary and social emotions: implications for developing a comprehensive neurology for emotions, repression, and the subconscious. Neuropsychiatr, Neurospsycology, and Behavioral Neurology, 7, 1-19.

Schiff, B., Guirguis, M., Kenwood, C., & Herman, C. (1998). Asymmetrical hemispheric activation and behavioral persistence: effects of unilateral muscle contractions. Neuropsychology, 12(4), 526-532.

Schiff, B., & Lamon, M. (1994). Inducing emotion by unilateral contraction of hand muscles. Cortex, 30(2), 247-254.

Schiffer, F. (1996). Cognitive activity of the right hemisphere: possible contributions to psychological function. Harvard Rev Psychiat, 4, 126-138.

Schiffer, F. (1997). Affect changes observed with right versus left lateral visual field stimulation in psychotherapy patients: possible physiological, psychological, and therapeutic implications. Comprehensive Psychiatry, 38, 289-295.

Schiffer, F. (1998). Of Two Minds: The Revolutionary Science of Dual-Brain Psychology. New York: The Free Press.

Schiffer, F., Anderson, C., & Teicher, M. (1999). EEG, Bilateral Ear Temperature, and Affect Changes Induced by Lateral Visual Field Stimulation. Comprhensive Psychiatry, 40, 221-225.

Schiffer, F., Zaidel, E., Bogen, J., & Chasan-Taber, S. (1998). Different psychological status in the two hemispheres of two split brain patients. Neuropsychiatry, Neuropsychology, and Behavioral Neurology, 11, 151-156.

Sperry, R. (1968). Hemisphere deconnection and unity in conscious awareness. Amer Psychologist, 23, 723-733.

Sperry, R. (1990). Forebrain commissurotomy and conscious awareness. In C. Trevarthen (Ed.), Brain Circuits and Functions of the Mind: Essays in Honor of Roger W. Sperry . Cambridge: Cambridge Univ. Press.

Sperry, R., Zaidel, E., & Zaidel, D. (1979). Self recognition and social awareness in the deconnected minor hemisphere. Neuropsychologia, 17, 153-166.

Springer, S., & Deutsch, G. (1998). Left Brain, Right Brain. New York: WH Freeman.

Teasdale, J., Howard, R., Cox, S., Ha, Y., Brammer, M., Williams, S., & Checkley, S. (1999). Functional MRI study of the cognitive generation of affect. Am J Psychiatry, 156(2), 209-215.

Teicher, M., Ito, Y., Glod, C., Andersen, S., Dumont, N., & Ackerman, E. (1997). Preliminary evidence for abnormal cortical development in physically and sexually abused children using EEG coherence and MRI. Annals of the New York Academy of Sciences, 821, 160-175.

Teicher, M., Ito, Y., Glod, C., Schiffer, F., & Gelbard, H. (1996). Neurophysiological mechanisms of stress response in children. In C. Pfeffer (Ed.), Severe Stress and Mental Disturbance in Children . Washington D.C.: American Psychiatric Association Press.

TenHouten, W., Hoppe, K., Bogen, J., & Walter, D. (1986).

Alexithymia: an experimental study of cerebral commissurotomy patients and normal control subjects. Am J Psychiatry, 143, 312-316.

Weiss, J., , & . (1993). How Psychotherapy Works: Process and Technique. New York: Guilford Press.

Wittling, W. (1995). Brain asymmetry in the control of autonomic-physiologic activity. In R. Davidson & K. Hugdahl (Eds.), Brain Asymmetry . Cambridge: MIT Press.

Wittling, W., & Pflüger, M. (1990). Neuroendocrine hemisphere asymmetries: salivary cortisol secretion during lateralized viewing of emotion-related and neutral films. Brain Cognit, 14, 243-265.

Wittling, W., & Roschmann, R. (1993). Emotion-related hemisphere asymmetry: Subjective emotional responses to laterally presented films. Cortex, 29, 431-448.

Wittling, W., & Schweiger, E. (1993). Neuroendocrine brain asymmetry and physical complaints. Neuropsychologia, 31, 591-608.

Young, A. (1982). Methodological and theoretical bases. In J. Beaumont (Ed.), Divided Visual Field Studies of Cerebral Organization . London: Academic Press.

Zaidel, E., & Rayman, J. (1994). Interhemispheric control in the normal brain:

evidence from redundant bilateral presentations. In C. Umiltà & M. Moscovitch (Eds.), Attention and

Performance XV: Conscious and Nonconscious Information Processing . Cambridge: MIT Press.