Confabulation & Delusional Denial: False Memories, learning, emotion, split-brain,
Reprinted (updated) from: The Journal of Clinical Psychology, 42, 845-860, 1986
by Rhawn Gabriel Joseph
Rhawn Gabriel Joseph, Ph.D.
Various forms of confabulation, including denial of illness (e.g., paralysis, blindness), and conditions that often give rise to these disorders, such as cerebral disconnection, disinhibitory states, incomplete information reception, and"gap filling" are discussed. On the basis of clinical observation and a review of a number of studies, it appears that confabulatory states frequently are associated with cerebral damage that involves the right hemisphere, notably, the frontal (often bilaterally) and parietal lobes--areas intimately involved in arousal, attention, information regulation, and integration. With certain forms of injury, initially there appear disturbances in the organization, integration, and assimilation of ideas and associations, such that large gaps appear in the information transmitted to and received by the language axis of the left hemisphere. It is argued that in these instances, the language areas act so as to fill these"gaps"with information that, although inappropriate, is linked in some manner to the fragments received. In contrast, frontal lobe damage sometimes results in gross disinhibition and cortical over responsiveness and, thus, speech release due to the flooding of the language axis (and other cortical regions) with tangential, fantastical, and grandiose associations. Other forms of confabulation also are reviewed briefly.
Ex: "Give me your right hand!" (Correct). "Now give me your left!" (The patient presented the right hand again. The right hand was held.) "Give me your left!" (The patient looked puzzled and did not move.) "Is there anything wrong with your left hand?"
Pt: "No, doctor."
Ex: "Why don't you move it, then?" (The left hand was held before her eyes.)
Pt: "I don't know."
Ex: "Is this your hand?"
Pt: "Not mine, doctor."
Ex: "Whose hand is it, then?"
Pt: "I suppose it's yours, doctor."
Ex: "No, it's not; look at it carefully."
Pt: "It is not mine, doctor."
Ex: "Yes it is, look at that ring; whose is it?"
Pt: "That's my ring; you've got my ring, doctor."
Ex: "Look at it--it is your hand."
Pt: "Oh, no doctor."
Ex: "Where is your left hand then?"
Pt: "Somewhere here, I think." (Making groping movements near her left shoulder).
It can be said that someone has lied when he knowingly possesses the truth and consciously attempts to deceive another individual. Curiously, it sometimes happens that a person half persuades himself that the lie he has told or is telling is true and then behaves accordingly. According to Sartre (1956), when a person attempts to conceal the truth from himself he acts in bad faith. For our purposes, we will call this behavior self-deception (Joseph, 1980). Self-deception implies a knowing and a not knowing, or, simultaneously telling a lie and believing it. Self-deception occurs when an individual would rather not be conscious of knowledge that he possesses and, thus, refuses to organize and attend to it linguistically (Joseph, 1980, 1982). Nevertheless, to resist acknowledging or thinking about a particular impulse, feeling, or idea requires an acknowledgement along with a disavowal; that is, to negate or deny an idea or impulse requires that it first be recognized so that it may be avoided.
A less common yet more extreme form of"lying,"or deception, is confabulation. Unlike self-deception, in which the individual resists admitting his true store of knowledge, the confabulator often appears to be unable to recognize the erroneous nature or absurdity of his statements even in the face of painfully (seemingly) apparent contradictory evidence. Hence, his replies to questions or statements may appear tangential, circumlocutious, irrelevant, and delusional. Moreover, rather than relinquishing an incorrect belief when confronted with contradictory information, these individuals may make further erroneous extrapolations or partially incorporate some aspects of the contradictory information within the confabulatory schema.
For example, when a 20-year-old individual who had lost control of his auto and suffered a serious head injury was questioned about his accident and injuries, he responded by"attributing his hospitalization to having been in an atomic explosion which occurred when his rocket ship had crashed. He stated that he was still filled with radioactive fluid and pointed to the numerous scars on his body to show where the doctors used needles to remove fluid"(Weinstein, Kahn, & Maltiz, 1956, p. 290). In another instance, a patient with a frontal lobe injury"continually propagated responses in an implausible manner. During one interview, when asked if he knew the place, he responded by stating that it was an air-conditioning plant (he was facing a window air-conditioner). When surprised was expressed about his wearing pajamas, he responded,"I keep them in my car and will soon change into my work clothes"(Stuss, Alexander, Lieberman, & Levine, 1978; p. 1167.)
Presumably, there is no"conscious"attempt on the part of the confabulator to deceive or lie; nor is the lie evoked in an attempt to please the interviewer or to avoid embarrassment, for he apparently believes his own misstatements, which are reported with"rocklike certitude"(Mercer, Wapner, Gardner, & Benson, 1977; Talland, 1961; Weinstein & Kahn, 1950, 1952l William & Rupp, 1938.) According to Talland (1961),"It serves no other purpose, is motivated in no other way than is factual information based on genuine data"(p. 370).
In many instances, however, the"genuine"data consists of over learned or exceedingly familiar material (e.g., condition of body parts), which then is reproduced erroneously, out of context and without regard for the patient's present circumstance (Berlyne, 1972; Mercer et al., 1977; Weinstein et al., 1956). Thus, confabulators appear to have extreme difficulty successfully utilizing environmental cues in making appropriate responses (Shapiro, Alexander, Gardner, & Mercer, 1981.)
Gap Filling, Disturbances of Time Sense and Memory
In some instances, such as that described by Sandifer (1946), it is apparent that the patient is oblivious to his present condition, whereas some investigators have argued that some of these individuals respond as though transposed in time; they reproduce and rely upon well-established, over learned impressions from the past in order to explain their condition in the present (Talland, 1961; Weinstein & Kahn, 1950; Weinstein et al., 1956; William & Rupp, 1938.) However, such explanations often appear bizarre or absurd. Hence, when one patient was asked why she couldn't move her paralyzed hand, she said,"Somebody has a hold of it." Another patient, asked whether anything was wrong with her hand, said,"I think it's the weather; I could warm it up, and it would be all right." One woman, when asked whether she could walk, said,"I could walk at home, but not here. It's slippery here." One patient, when asked whether anything was wrong with his arm, said "It's just a little stiff--from the cold or something." Another, when asked why he couldn't raise his arm, said"I have a shirt on." A common explanation was"stiff joints,"one that could have been accepted if the same patients had not claimed that they could move their paralyzed extremities (Nathanson, Bergman, & Gordon, 1952, p. 383). Thus, the content of confabulation may border on the bizarre and fantastical as loosely associated ideas become organized and anchored around fragments of present experience.
In another instance described by Talland (1961), an elderly woman"after ten years' hospitalization continually maintained that she had been brought in the previous day for observation, and would be sent back within a day to the hotel where she had formerly lived with her husband, and conducted the life of a well-to-do lady of leisure. She seemed unaware that the conditions of that very agreeable life had long since ceased to operate. She never spoke disparagingly or resentfully about the setting of the mental hospital or her fellow inmates. All that barely existed for her. One would think that an elaborate facade like hers could not be sustained within immense effort, yet not once did she betray her disbelief in anything she pretends"(p. 375). Although this form of confabulation could be viewed as arising from"an arrest of experiential time,"this and the forms already mentioned also could be due to an attempt to escape perplexity by employing the mechanisms of normal remembering. Thus, the patients explain their present circumstance via the generation of a memory or hypothesis (which they mistake as truth) that is based on circumstances with which they are most familiar.
A disturbance in time sense, however, cannot explain fully the failure to employ observable cues (e.g., paralysis, the doctor's explanation of one's illness, etc.). Rather, in some cases there appears to be a comprehension deficit of sorts, whereby the individual (or his language centers) does not appear to have access to his present situation; that is, there appears to be a failure to store these experiences in memory, such that the patient relies upon information from the past to explain the"fragments"of reality that are experienced in the present.
For example, a patient who was suffering from partial-complex seizures began to demonstrate automatism while he was being examined. He ceased to speak, and his hands began to repetitively pick and twist at his clothing (as though he were attempting to remove lint). His hands continued up (fiddling with the buttons of) his shirt, and then he stood up. The patient's hands then traveled up the side of his face, and he removed the hat he had been wearing and began turning it between his hands in a repetitive and stereotyped manner. Finally (after about a 2-minute period), he suddenly stopped and stared down at his hand and hat with perplexity. At that point, he was questioned as to his reasons for taking off the hat. He stated matter of factly that he thought there was something in it, and he reached inside (making groping movements).
Presumably, during automatisms and absence states there is abnormal activity in the inferior (uncal) regions of the temporal lobes (Penfield & Perot, 1963). Hence, memory of events that occur during this time period is not established. In that all other attempts to elicit confabulation from this patient was unsuccessfully, it appears that in the single instance of confabulatory responding, once"consciousness"returned and events again began to e recorded in memory, the patient was faced with the remnants of behavior (i.e., the hat in his hands), which he then attempted to explain. In this regard, the patient was faced with a"gap"in his knowledge, which he then attempted to"fill." Hence, the same processes that"normal"individuals utilize to explain various behaviors were employed.
According to Talland (1961),"in a very wide sense confabulation always fills gaps, but not in the sense that the patient is aware of these gaps. When he is aware of the gap he usually answers with a plea of ignorance"(p. 364). However, it remains a puzzle that a patient who denies the existence of a paralyzed arm may have a"gap"in his knowledge of his condition. For example, Gerstmann (1942) describes a patient with left-sided hemiplegia who"did not realize, and on being questioned denied, that she was paralyzed on the left side of the body, did not recognize her left limbs as her own, ignored them as if they had not existed, and entertained confabulatory and delusional ideas in regard to her left extremities. She said that another person was in bed with her, a little Negro girl, whose arm had slipped into the patient's sleeve"(p. 894).
Nor can we explain this phenomenon as a memory deficit or a disturbance in time sense, for, clearly, memories such as these do not in all probability exist. Although in some cases we may be presented with confabulatory"gap filing,"the appearance of confabulation does not always appear to be related directly to memory disturbances (Talland, 1961) and, thus, cannot be due to forgetting, for example, that one has a left arm. Although confabulation sometimes appears in conjunction with Korsakoff's disease, it is often only secondary, or even absent, and usually appears only in the early stages of memory loss (Talland, 1961). Moreover, confabulation does not always appear in conjunction with amnesia (Mercer et al., 1977; Weinstein et al., 1956) and is usually absent in pure memory deficits (Berlyne, 1972; Zangwill, 1966).
In general, in cases that follow cerebral injury or dysfunction, there appear to be certain features that are characteristic of confabulators--but by no means all confabulators. In many instances, there appear to be difficulties in the monitoring of responses, withholding answers, inhibiting the flow of tangential and circumstantial ideations, and in utilizing external cues to make corrections (Berlyne, 1972; Mercer et al., 1977; Shapiro et al., 1981; Stuss et al., 1978; Talland, 1961). Also, many of these individuals have been noted to demonstrate marked perservatory tendencies (Shapiro et al., 1981) and difficulty in shifting response sets (Berlyne, 1972; Mercer et al., 1977; Shapiro et al., 1981; Stuss et al., 1978). In part, there appears to be a deficit in the ability to correctly label or symbolically organize one's feelings, thoughts, sensations, desires, impulses, etc. (Joseph, 1982; Weinstein & Lyerly, 1968; Weinstein et al., 1956), such that the individual communicates in abstract metaphors or demonstrates an inability to inhibit the expression of inappropriate ideas that normally would be filtered out. In this regard, the content of the confabulation may border on the bizarre and fantastical as loosely associated ideas become organized and anchored around fragments of one's present experience.
On the other hand, by nature of their erroneous responses, it is sometimes apparent that the correct information is not wholly available--at least to those areas of the cerebrum that are responsible for the expression of this information (Geschwind, 1965; Joseph, 1982; Joseph, Gallagher, Holloway, & Kahn, 1984).
Confabulation is not a unitary syndrome and does not appear to result from a specific type of lesion or in conjunction with a particular constellation of disorders. Rather, there appear to be many types of confabulation (some of which overlap), as well as different degrees to which the tendencies are elicited. In some instances, confabulation is expressed as a form of delusional denial, such as when a blind patient claims to see or a paralyzed patient claims he is able to move his arm. In others the content is clearly fantastical (e.g.,"I crashed in a rocket") and may include the reporting of fictitious events or grandiose ideas ("I'm rich.""I'm a congressman.") or other delusional material. In some cases, the tendency to confabulate is secondary to speech release (or"motor mouth"), and a loosening of associations such that tangentially related ideas come to be linked together and erroneous conclusions are reached.
The Filling of Gaps in Information Due to Disconnection
Confabulation also often results from a tendency to engage in gap filling, which, in turn, may be secondary to memory loss or intra/inter-cerebral disconnection. For example, it has been suggested (Geschdwind, 1965; Joseph, 1982) and demonstrated (Gazzaniga & LeDoux, 1978; Joseph et al., 1984) that confabulation may occur when the language centers of the left hemisphere are isolated from sources of information about which the patient is questioned, such that complete and accurate information is not fully available. In these instances confabulation may occur as a result of an attempt (e.g., by the language axis) to fill the gaps in the incomplete information received with associations and ideas that are related in some manner to the fragments available (Joseph, 1982; Joseph et al., 1984; Talland, 1961).
Moreover, disconnection of one brain area from another may result in a failure to correct erroneous statements because as disconfirming evidence is not always accessible--e.g., a brain area disconnected, for example, from the language centers is unable to communicate with this region so as to supply information. However, confabulatory statements, although erroneous, can contain accurate elements (if the disconnection is only partial), around which erroneous, albeit related, ideations are anchored.
In cases presented by Redlich and Dorsey (1945), individuals with gross visual disturbances due to injuries in primary and/or visual association areas continued to claim they could see even though they bumped into objects. Apparently, these individuals maintained these claims because when information that concerned blindness was pointed out to the patients, i.e., that they were describing inaccurately events or objects or were bumping into things, the patients responded to ideational associations related to seeing that might explain not seeing (as this information was not available):"It is a little dark.""This is not a bright day." When asked about objects held before them, these individuals also confabulated by apparently calling upon intact pathways or associations that concerned"objects"that they claimed to see. Thus, they utilize the information that is available and comprehend only that which they can utilize. The individual or the"they"to whom we are referring, however, is really only an aspect of the whole--the language axis (Joseph, 1982). In this regard, the speech area of the left hemisphere does not know that it is blind because information that concerns blindness cannot be transmitted to it (i.e., because of disconnection and damage to linking fibers).
According to Geschwind (1965), when the speech area is disconnected from a site of perception, then the speech area will be unable to describe what is going on at that site. This is because"the patient who speaks to you is not the 'patient' who is perceiving--they are in fact, separate." Confabulatory responses are, thus,"attempts to fill in the information available to the speech area." These"gap"fillers, nevertheless, remain erroneous substitutes.
Confabulation and Limited Interhemispheric Information Exchange
In cases of complete section of the commissures (i.e.,"split-brain"), each hemisphere appears ignorant of the cognitive activities that are occurring in the other. However, when the brain is only partially split, some information transfer will occur, albeit to a very limited and incomplete degree (Joseph, 1982, 1986). For example, when the non-speaking cerebral hemisphere of one patient (with sectioning of all but the anterior portion of the callosum--the rostrum) was presented with visual-pictorial images via tachistoscope, his verbal descriptions were contaminated with errors, gross embellishments, and other falsehoods--although all statements contained some accurate descriptive elements. Presumably, information transfer from the non-speaking to the language dominant hemisphere was incomplete, such that the speaking hemisphere attempted to make sense of the limited information received via confabulatory"gap filling."
In a similar case presented by Gazzaniga and colleagues (Gazzaniga & LeDoux, 1978; Gazzaniga, Volpe, Symlie, Wilson, & LeDoux, 1979), a"split-brain"patient with an intact anterior commissure typically would respond with concrete and accurate two- or three-word replies, such as"guy with a gun"when a complex picture was presented tachistoscopically to the language dominant left hemisphere. When the same stimulus was presented to the right hemisphere (which required transfer from the right to the left hemisphere language centers), the patient would respond with elaborate, detailed, and vivid descriptions that bore little or no relation to the actual content of the picture, but which, nevertheless, contained some correct elements of the original stimulus, around which other associations were erroneously anchored: "Gun, hold up…he has a gun and is holding up a bank teller, a counter separates them." Furthermore, this patient's left hemisphere apparently believed the largely erroneous descriptions offered in these instances, for as noted by Gazzaniga and LeDoux (1978), it did not"offer its suggestions in a guessing vein but rather as a statement of fact"(pp. 148-149).
Gap Filling and Information Degradation
An important feature of the gap-filling hypothesis is that notion that information degradation and confabulation should be related directly, such that the larger the"gap,"the more likely the individual is to respond with confabulation. Recently, this relationship was examined directly and verified experimentally. Noting the incomplete status of cerebral mantuarion and callosal myelination during the first decade after birth and the findings of a number of investigators that demonstrate or suggest that select forms of information are, at best, transferred only incompletely between the two brain halves in young children, a paradigm similar to that of Gazzaniga and LeDoux (1978) was employed to assess for similar confabulatory tendencies among children (Joseph et al., 1984). It was found that young children not only function as though the two halves of the brain are partially disconnected, they respond with confabulatory gap-filling in a manner similar to that of the partial split brain patient of Gazzaniga and colleagues when complex visual-pictorial stimuli were projected to the right as compared to the left (language dominant) hemisphere. Moreover, a perceptual inclusion score (defined as the number of major stimulus elements reported) was employed, and a significant inverse relationship (r= -.484, p<.001) was found between this variable and confabulation such that the fewer elements reported, the more likely a subject was to confabulate. Thus, in response to the gap in information received (as information was transferred from the right to left hemisphere), information somehow was added such that the larger the gap (i.e., the lower the inclusion score), the more likely the subject was to confabulate.
Interestingly, not only does incomplete information transfer from the right to left hemisphere often result in confabulatory"gap filling,"but damage that involves the right cerebrum (including the right parietal lobule and frontal lobes) frequently results, at least initially, in confabulatory responding (Bisiach & Luzzatti, 1978; Critchley, 1953; Freeman & Watts, 1943; Gainotti, Messerlie, & Tissot, 1972; et al.). In general, fantastical and delusional (including grandiosity) confabulations are seen more frequently after right frontal damage, whereas denial usually accompanies posterior or frontal destruction, at least initially. Of course, it is important to note that destruction that involves the frontal, parietal, or other right hemisphere nuclei does not necessarily result in confabulatory responding; in the less extreme case, they may merely produce tangential ideation.
Frontal Lobe Damage and Delusional/Fantastical Confabulations
Despite the diverse forms of cerebral injury that may give rise to this disorder, confabulation often is though to be related to memory dysfunction and is associated most closely with Karasakoff's psychosis and the accompanying amnesic syndrome (cf. Adams & Victor, 1981; Talland, 1961). Thus, presumably, these patients confabulate due to the failure to retain newly presented information. However, the content of their confabulatory statements often is confused, disoriented, and has little association with memory loss per se.
For example, one patient with a long history of alcohol abuse and a diagnosis of Karasakoff's disease was noted, after admission to the hospital, to be extremely confused, disoriented, and forgetful. Two weeks prior to admission and for the preceding 17 years, the patient had been employed by the Civil Service. For the next 30 years after admission, the patient constantly asked directions to the bathroom, could not find his room, locker, or bed. Also, during this period, he had little or no realization that he was a patient or even in a hospital and responded with much confabulation when questioned in this regard. For example, when nursing staff attempted to provide him with medication and vitamins, he would respond ,"What is this for? I've got to get out of here and go to work in the garage downstairs." Or,"I Just stopped by for a checkup. I've got to get back to work." When examined and interviewed by this author, he repeatedly explained,"I just got here. I work in the garage downstairs. It was nice meeting you, but I have to leave now and empty the garbage." When informed that he was in the hospital and had been so for 2 weeks, he became very concerned, suspicious, and responded quite seriously that he had been sent here by this employers to do some work. When asked what kind of work, he replied hostilely,"I just came here for lunch. I do not belong here. I'm suppose to work in the garage. Now would you please tell me how to get to the garage."
EEG failed to demonstrate any abnormalities. However, CAT scan indicated marked cortical atrophy that involved the frontal regions bilaterally, as well as dilated ventricles. Nevertheless, 3 months after admission the patient's confabulatory tendencies completely cleared. A profound disturbance of verbal and visual memory continued to be demonstrated.
Although chronic alcohol abuse has been associated frequently with destruction of nuclei within the frontal lobes or hippocampus, Victor, Adams, and Collin (1971) have reported that individuals with memory loss and Korsakoff's disease who are brought to autopsy frequently will have damage that involves primarily the dorsal medial nucleus of the thalamus--a thalamic nuclei with major inter-relaying fiber pathways that project to and from the frontal lobes (Akert, 1964; Brodal, 1981; Nauta, 1964).
It is now well established in both animal and human studies that damage that involves the dorsal medial nucleus, including tumors, surgical lesions, and thalotomies, will result not only in memory disturbances (McEntee, Biber, Perl, & Benson, 1976; Means, Harrell, Mayo, & Alexander, 1974; Smythe & Stern, 1938; Spiegel, Wycis, Orchinik, & Freed, 1955), but also in behavioral over-responsiveness and disinhibition, as well as increased cortical responsiveness in primary and secondary associational receiving areas. (See Skinner & Lindsley, 1971; Yingling & Skinner, 1975). Hence, presumably, such damage results in a severe disruption of the frontal-thalamic pathways involved in arousal and inhibition.
Severe damage that involves or is limited to the frontal lobes, the right frontal lobe in particular, characteristically gives rise to gross disinhibition and excessive cortical and behavioral arousal (Como, Joseph, Fiducia, & Siegel, 1979; Lineberry & Siegel, 1971; Sterman & Clemente, 1962), as well as inappropriate emotional reactions, affective abnormalities, alterations in personality, including euphoria, childishness, egoism, irritability, exuberance, and, at times, wild confabulatory responding (Davison & Kelman, 1939; Freeman & Watts, 1943; Hecaen, 1964; Hillbom, 1960; et al.).
For example, a 27-year-old, white, single male was hospitalized by his family, who complained that he was becoming unmanageable, keeping late hours, acting silly and disoriented, and recently had made threats against them. CAT scan indicated decreased density in the frontal regions, particularly on the right side (i.e., cortical atrophy). Upon admission, the patient was found to be severely disoriented; he demonstrated labile affect, agitation, and pressured speech. He was also markedly confabulatory and claimed at times to be a police officer, a doctor, or to be married to various members of the staff. Over the course of his hospitalization, it was noted that he incontinent for urine, neglected his personal appearance, and was emotionally labile, crying at one moment and suddenly bursting into laughter the next. He also was easily frustrated, frequently assaulted other patients, and was loud and abusive. In addition to his poor impulse control, the patient had excessive appetite and thirst; he ate off dirty trays and drank voluminous amounts of water and other liquids. During testing, this individual frequently engaged in repetitive speech activities, such that he would repeat phrases and sentences until interrupted by this examiner. When questioned about a scar on this left hand, received after a fall in a shower, the patient replied,"I got that from the Japs. I was shot through the hand while on guard duty…etc." In addition, the patient was quite tangential. For example, when asked, What did you get for Christmas?"the patient replied,"I got a record player and a sweater." (looking down at his boots)"I also like books, westerns, popcorn, peanuts and pretzels." When asked why he was in the hospital, he replied,"I'm a doctor. I'm here to protect people."
According to Luria (1978), after damage to the frontal lobes,"cortical tone falls accordingly. The cortex is in an inhibitory 'phasic' state and unable to distinguish between strong, dominant foci of excitement and irrelevant foci disappear [and] a disturbance of the selectivity of connections arises. The patient loses the precise orientation in space and, in particular, in time; he considers that he is in some indefinite space: 'in the hospital,' 'at work,' or 'at the station.' Sometimes this primary disturbance of orientation is compensated by naïve uncontrollable guesses: seeing the white gowns and white hats of physicians, the patient declares that he is 'at the baker's,' 'at the barber's.' Such a patient cannot answer when he is asked where he was the same morning or night before and the irrepressible traces of past experience lead him to fill this gap with confabulations: he says he was 'at work,' or 'walking in the garden,' and so on. The contradictions between his assessment and the real situation cause such a patient little confusion because the rapidly disappearing traces of his impressions do not provide an opportunity for reliable, critical, comparisons"(pp. 23, 25-27).
Delusional Denial and Left-sided Inattention/Neglect
Lesions of the right hemisphere, in particular the posterior regions, often produce denial (i.e., confabulatory explanations) and neglect--a failure to become consciously aware that half the body (the left half) is in some way dysfunctional or even that it exists (Critchely, 1953; Denny-Brown, Meyer, & Horenstein, 1952; Roth, 1944, 1949; Sandifer, 1946). Typically, the lesions involve the inferior parietal lobule and surrounding tissues and include the second occipital convolution (Critchley, 1953; Nielson, 1937; Roth, 1944, 1949). However, lesions in the frontal lobes also have proved responsible for this deficit (Heilman, 1979).
Neglect may be accompanied by anosognosia in cases in which individuals requested to perform some response with the neglected part either will demonstrate the requested movement with the opposite arm or will not move at all. In either case, they are likely to swear that they complied. Confronted with their unused or immobile limb, they may deny that it belongs to them or swear that there is nothing wrong with it. However, this latter behavior may occur with or without hemiplegia and with or without symptoms of neglect. That is, the patient may recognize the presence of his left arm, but will claim that the limb belongs to someone else, such as the patient in the next bed or the attending physician. (See Sandifer, 1946). In addition, although these patients often fail to perceive stimuli applied to the left side, sometimes tactile and pain sensations are acknowledge, but are referred from the neglected (affected) limb to the one that is still functional (Critchley, 1953). Hence, when the left (neglected) elbow is pinched, the patient may claim to have"felt"the sensation somewhere upon the right arm. The neglect, however, may extend well beyond the left limbs, but may include all of auditory-physical-visual left-sided space.
For example, Denny-Brown et al. (1952) described one patient who seemed to have absolutely no comprehension of her disability, which included a slight motor deficit of the right side. During her initial examination, these authors found the patient in bed, with her left hand and fingers extended into the air and with the left side of her face and hair completely disarray and the right side set neatly in braids. Her deficit extended, in fact, to every sphere of activity that occurred on the left side; she had no knowledge of objects placed in her left hand and was unable to dress or groom the left side of her body.
However, the lesions does not have to be confined to the right hemisphere, for Denny Brown and Banker (1954) have described a 36-year-old male with a similar neglect, but of the right side of space due to left parietal-occipital damage. Similarly, this male possessed clear consciousness and was oriented to the three spheres. Nevertheless, he repeatedly demonstrated a tendency to throw his right arm away and stated that it didn't belong to him. Moreover,"the patient denied feeling pain, temperature, or touch on the right side of the body, and when questioned replied: 'How can I when it doesn't belong to me?' He continued to throw his right arm from the bed and stated, 'It must belong to someone else.' When he was being helped into a hospital gown, he became agitated and refused to put his right arm into the sleeve' (p. 303).
According to Denny-Brown et al. (1952), the indifference, neglect, and presumably, the resulting confabulation are due"to the lack of stimulus value,"which results from"a poorly resolved cortical reaction on that side,"which, in turn, is partly a function of dissociation from the motor cortex (p. 466). Similar to this is the notion of Heilman, Schwartz, and Watson (1978), who postulate that unilateral neglect is due to a breakdown in the orienting response to incoming stimuli. Critchley (1953) also has argued that the defect is attentional, a result of a lowering of the stimulus strength on the affected side, such that imperceptions occurs due to competition with stimuli from a coactive stimulus input from the nonaffected side. Interestingly, increasing the stimulus strength is not sufficient to draw attention to the neglected part (Head, 1920).
On the other hand, it is possible that when the language-dominant (which is usually the left) hemisphere denies ownership of a paralyzed (unilateral) extremity, it is, in fact, telling the truth. That is, a paralyzed arm (the result of right cerebral damage) does not belong to the left hemisphere, but to the right--a cerebral mass that is (for whatever reason) unable to communicate with the left cerebrum. The right arm, not the left, belongs to and is controlled by the left cerebrum.
Disconnection, Disinhibition and Assimilation Errors
Inevitably, in order for an individual to confabulate, erroneous information must become integrated in some fashion so that the confabulated response can be expressed. When the frontal lobes are compromised, there is much flooding of the association and assimilation areas with tangential and irrelevant stimuli and information, much of which is amplified erroneously completely out of proportion to more salient details, and a proportion of which appears due to the disinhibition of impulses and ideations that normally are filtered out (or at least denied linguistic expression). Consequently, salient and irrelevant, highly arousing and fanciful information is expressed indiscriminately.
Confabulation is also likely when the language axis is functionally isolated from a particular source of information about which the patient is questioned. Such a condition may result from damage in the white matter of fiber tracts between the speech area and another brain region, lesions in the primary or secondary associations areas with which it is expected to communicate, disturbances or immaturity of the corpus callosum that prevent interhemispheric information transfer, and, as noted, lesions within the right cerebral hemisphere.
According to Geshwind (1956),"the destruction of association cortex or fibers corresponds to a totally unphyisological state--one in which no message is received by the speech area." When no message is received and when the speech centers are not informed that no message is being transmitted, the speech centers instead report messages received from other areas. The language axis, nevertheless, cannot, in itself, determine when the messages received are erroneous because errors must be detected, reported and/or corrected by brain areas normally responsible for the analysis of that information (e.g., visual cortex analyzes visual stimuli). When the area is prevented from communicating with the language axis, the language axis of the left hemisphere will not know that it does not know because it reports only what is transmitted to it.
Hence, in response to a gap in information of the speech areas begin to receive and respond to random messages from intact areas, or to associations, ideations, or stimuli that are tangentially related in some manner to the fragments received or to the question at hand (Joseph, 1982; Joseph et al., 1984). That is, when the individual (or his language areas) is not able to access and assimilate all relevant information,"substitute"material may be assimilated in place, such that, depending on the extent of damage, confabulation may well be the result.
Confabulation, Self-deception, and the Normal Brain
Admittedly, there appear to be many different types of confabulation, which, in turn, are due to a number of factors and forms of brain injury, some of which were not addressed by this paper; consider, for example, the concept of "false memories."
Nevertheless, the striking feature of confabulatory responding, regardless of locus of damage, disease type, or neuronal immaturity, is that the individual often does not seem to realize the absurdity or erroneous nature of his or her comments nor to utilize effectively feedback from the environment to correct misstatements.
It must be stressed, however, that the aspect of the individual that confabulates and reports these erroneous or absurd statements is the language axis (i.e., Broca's & Wernicke's area, the inferior parietal lobule, thalamus; Joseph 1982), a multi-channeled neuronal network that is, in itself, without judgment, morals, or, when considered in isolation, comprehension. Rather, this dynamic interconnected neuronal linguistic network acts only to assimilate what is available to it, advancing and organizing information that is received from other regions of the brain. Because the language axis is dependent upon these other brain areas to analyze and determine information relevance, it cannot, in itself, realize the absurdity of the positions it attempts to advance even when the brain is undamaged.
Confabulation (or rather, in the less extreme case, self-deception) does not occur only among severely brain-injured individuals, but, rather, is sometimes the byproduct of the normal process via which explanations for behaviors, impulses, or other actions are provided; particularly those that have causes that are not immediately and/or completely amenable to linguistic translation or interpretation (e.g.,"gap filling"). Although confabulatory, in many instances the explanations seem reasonable, innocuous, and accurate, although completely erroneous.
For example, Nisbett and Wilson (1977) describe an experiment in which shoppers were asked to indicate a preference among four supposedly different (yet identical) nylon stockings. A very significant and pronounced position effect was noted such that most chose the stocking to the right of the display. When asked their reasons, no one mentioned position, but instead commented on differences in color, texture, etc.--although all of the stockings were identical. Moreover, when position effects were mentioned by the experimenters, most of the shoppers were disbelieving.
In other instances, confabulation is merely the result of an attempt to provide explanations that are acceptable to the self-image. Indeed, it often happens that people will make a"slip of the tongue,"“speak without thinking,"make foolish statements, act on sudden impulses or in a peculiar or insulting manner, or engage in various objectionable activities, and yet no even realize that an inappropriate act was committed. Of course, if pointed out, this does not prevent the left hemisphere (i.e., the speaking half of the brain) from inventing numerous explanations or denials. If questioned, the individual may claim to have"no idea"as to"what cam over them"or, in other instances, dismiss the action as a rare and momentary lapse that is not as bad as it seems. Such explanations commonly are produced, for example, by young women who have been successfully seduced. (See Joseph, 1980, p. 777).
Although such actions and denials have been classified as various forms of resistance, repression, etc., one need not posit the existence of an unconscious in order to explain the motivational origins and mechanisms involved (Joseph, 1980, 1982). Rather, in many instances these behaviors, denials, and conflicts are the result of the differential organization of the right and left cerebral hemisphere (as well as that of the limbic system) and their inability to completely communicate and engage in information transfer and exchange (e.g., something is lost in the translation and during transfer). In certain instances, one brain half often has little or no knowledge (much less understanding) of what is occurring in the other.
Indeed, the right and left cerebral hemisphere not only speak different languages (insofar as visual-spatial, nonlinguistic, social-emotional, sequential, and other processes are concerned), they process and express select forms of information that often cannot even be recognized or detected by the other half of the brain.
Even intra-hemispherically we know there are areas that due to their specialization (e.g., auditory cortex) are incapable of processing order forms of information. Hence, the visual cortex never will sing and the auditory cortex never will see. If auditory information were transmitted to primary visual cortex (area 17), it never without be recognized for what it is.
Similarly, for the right v.s. left cerebrum, some forms of information simply do no co-exist. This remarkable relationship not only provides the foundation for confabulation and self-deception (in many instances), it also provides the matrix from which other forms of thought may arise via the interpretive process (e.g., dreaming and creativity).