social cognitive factors in brain injury-associated personality change
TRANSCRIPT
BRAIN INJURY, 1994, VOL. 8, NO. 3, 265-276
Social cognitive factors in brain injury-associated personality change
J A C Q U E L I N E S A N T O R O T a n d M A R Y S P I E R S $ ?New Medico Rehabilitation and Skilled Nursing Center at Cortland SNeuropsychology Graduate Program, Drexel University, USA
(Received 6 Bcetnber 1992; accepted 21 January 1993)
Often social difficulties are the most enduring difficulties after a head injury. The social deficits most frequently reported by relatives 6-12 months post-injury include egocentric styles of social interaction characterized by family members as a change in the head-injured patient's personality style. The described characteristics of head-injured patients in terms of social perspective-taking abilities are similar to those of children reported in the cognitive develop- mental literature. To demonstrate the nature of the social deficits in head-injured participants, social perspeaive-taking paradigms in the development literature were used to construct a task to be administered to both head-injured and non-head-injured adults. Results of the comparison between the two groups suggest deficits in social perspective-taking abilities in head-injured adults similar to the level demonstrated by pre-adolescent children.
Introduction
During the first year following a head injury, just as head-injured individuals are starting to return to normal physical hnctioning, significant others often note a change in 'personality'. Approximately 50% of relatives report changes over the first 3 months, and nearly 66% report changes by 6-12 months [l]. This change in personality has been described by relatives as increased irritability, frustration, aggressiveness, childishness, egocentricity, impulsivity, lack ofjudgement and insight, talkativeness, and inappropriate affectionate expression [ 1-61.
Despite these reports by relatives, when head-injured individuals are asked to rate themselves, they see themselves as no less talkative, friendly or caring than before the injury [5]. Although the head-injured patient does not typically acknowledge a change in personality, the patient frequently is aware of social dyshnction. Head- injured patients whose injuries occurred 6 months earlier report greater levels of distress than those in acute stages [7]. As a whole, the social habits of head-injured individuals involve fewer social outings, social contacts, worWschoo1 activities, and leisure activities [6]. Relationships may be characterized as acquaintances with no adult commitment or intimacy [2,6]. Finally, those who return to work tend to show fewer personality changes than those who do not .return to work [2]. So, even beyond the social misfortune there is often an economic disadvantage to having those personality attributes post-injury.
Two perspectives have been stressed in the literature which attempt to explain the perceived personality change experienced by head-injured patients. Although these perspectives are not mutually exclusive, these emphasize different processes as
Requests for reprints and correspondences should be sent to Jacqueline Santoro. New Medico Rehabilitation and Skilled Nursing Center at Cortland, 28 Kellogg Road, PO Box 5510, Cortland. NY 13045. USA.
0269-9052194 $10.00 0 1994 Taylor & Francis Ltd.
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266 J. Santoro and M. Spiers
instrumental in the apparent behaviour change. The &st point is derived fiom a simple cognitive deficit model. The second is derived from a biopsychosocial perspective. Both will be discussed in turn.
A number of cognitive difficulties result from head injury emanating from both its direct effects (i.e. contusion, rupture of blood vessels, strain and shearing of white- matter tracts) and its secondary effects (i.e. expanding haematoma, increased intracranial pressure, hydrocephalus). These range fiom focal deficits such as paralysis and aphasia to a general lowering of cognitive functioning such as loss of arousal and concentration abilities. All of these have an impact on cognitive functioning. Since head injury is a diffuse process, it is difficult to localize an area of damage responsible for social dyshnction. The simple cognitive model which is based on ablation and psychosurgical studies, however, has emphasized the importance of localizing an area of the brain that is responsible for social-emotional functioning.
Several examples of changes in social hnctioning after damage to specific areas of the brain involving the limbic system, frontal lobes, reticular system, and right hemisphere have been cited in the literature in support of the cognitive deficit perspective. Limbic system damage experienced during head injury results in the changes in behaviours [8]. The arousal qualities of emotion [9] depend upon the cortico-limbic-reticular loop [ 101. Damage to these areas occurring with stretching white-matter pathways may result in inappropriate affectionate expression to a lack of emotional expression [8]. Damage at the level of the second functional unit due to white-matter damage interconnecting the secondary areas to the tertiary areas may result in an inability to process visual affective facial expression or intonational patterns of speech [8]. Finally, frontal lobe or third hnctional unit damage results in difficulties in initiating, shifting responses, stopping ongoing behaviours, self-awareness, and insightfulness [8]. These are cited as perhaps the foremost causes of apparent personality change following closed-head injury [8]. Filskov, Grimm and Lewis [l l] suggest that fiontal association areas are important for understandmg the way in which behaviour impacts upon others. A concrete attitude with the inability to modifj. behaviour, both due to problems in self-evaluation and perseveration, result in difficulty getting along with others [l 11.
An alternative perspective involving a biological, emotional, and social interaction emphasis explains the reason for the superficiality of relationships and the avoidance of social interactions. Specifically, Boll and Barth [12] stated that due to the distractibility, irritability, complaints of physical difficulties, difficulty delaying gratification, frustration, impulsivity, and lack of self-critical behaviour, the closed- head-injured person receives the brunt of the hostility of others. Central to this model are the cognitive difficulties experienced by the head-injured individual. These deficits cause an inability to interpret and react appropriately to social situations which result in anger on the part of social participants. As a result, the head-injured individual withdraws from social interactions.
Neither the simple cognitive deficit model nor the biopsychosocid model fully explains the process involved in the breakdown in social functioning, because these are based on assumptions extrapolated from cognitive deficits. It is unlikely that either of these perspectives or emphases are solely responsible for the behaviour changes after head injury. First, any type of cognitive deficit will be a social impediment. It is frequently not the case, however, that a single cognitive deficit and a single area of brain damage will result in a lack of awareness of socially appropriate behaviour. For example, it is unlikely that any one cognitive deficit would result in a person
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Cognitive factors in perspective taking 267
talking about irrelevant issues and interrupting others in a discussion group. Second, it is equally unlikely that reinforced behaviours would result in this sort of socially inappropriate behaviour because fiequently individuals emerge immediately afler their injuries with changes in social behaviours. Therefore, it appears necessary to place emphasis on another aspect of social functioning in order to understand the behaviour changes present following a closed-head injury.
Developmental theorists have focused on social functioning in children. From a neuropsychological perspective on development, the capacity to take another3 point of view is not possible until the fourth stage of development. In this stage, children gain the ability to think abstractly. This occurs when tertiary areas of the second functional unit of the brain develop. Hallmarks of this period include the ability to do arithmetic, read, write, do logical processes, analogize, name, categorize, and distinguish directions [13]. At the fifth stage the tertiary areas of the frontal lobes develop. This allows children to consider flexibly multiple abstractions and weigh input from a variety of internal and external sources prior to responding. Cognitive models of social interaction correspond to the onset of these abilities.
These cognitive models of normal social development may be useful in further understandmg the processes involved in the behavioural difficulties of the head-injured. Miller, Kessel, and Flavell [ 141 studied the development of recursive thinking (or the ability to think about what others are thinking) as it relates to perspective-taking development in children. Miller et al. [14] proposed that children acquire the ability to recursively think between the ages of 7 and 9 years. The level of recursive thinking is at what is termed the single-loop recursion level (e.g. Larry thinks Richard thinks), which means thinking about what another person could be thinking or feeling. Less reliance on perceptual input (cues from the environment) and more reliance on abstract reasoning abilities are cited as the means by which recursive thinking occurs. Selman [ 151 suggests that children are able to differentiate their viewpoints from the viewpoints of others, and make decisions as to whether or not the viewpoints of others are similar to their own, at this stage. With greater abstraction, symbolic abilities, and mental flexibility associated with tertiary area devlopment, children become more capable of perspective-taking and, specifically, single-loop recursions.
With the development of tertiary areas of the second functional unit and third functional unit, children develop the ability to perform perspective taking tasks. Newman [16] asserts that, prior to the development of recursive thinking abilities, children gain the ability to differentiate and associate stimuli to others. Prior to the ability to assert mutual knowledge states, the ability to discriminate and associate stimuli would be necessary. Therefore, prerequisite to the development of mutual knowledge is secondary area development. In the next step, increasing tertiary area development is required to do the levels of recursive thinking. Associatiops between perceptual input and conceptual, logical input are necessary to think recursively. Therefore, tertiary area development is required to do any level of recursive thinking, because it is in these areas that associations are made between sources of perceptual input.
After closed-head injury, in particular due to a motor vehicle accident, acceleratioddeceleration of the skull almost inevitably results in some frontal damage. Presumably, the third functional unit tertiary areas are damaged. If in fact, as asserted here, children are incapable of recursive thinking prior to the development of the tertiary areas, then adults whose tertiary areas are damaged should be equally incable of recursive thinking.
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Therefore, closed-head-injured adults, because of frontal lobe damage, may show similar recursive thinking abilities as have been previously demonstrated in children [14]. In support of this proposal, the patterns of anatomical damage after closed-head injury resulting in third functional unit tertiary area damage have had some specific cognitive effects-mental inflexibility, concrete thinking, and stimulus- bound thinking. In fact the areas damaged in closed-head injury are exactly those areas which develop at the same time recursive thinking abilities become possible. Children seem to develop recursive thinking as they moved from concrete thinking to logical, symbolic, abstract thinking, and from mental inflexibility to mental flexibility. .Do adults return to more primitive social abilities (inflexibly non-recursive) when damage occurs to these areas?
It is expected that recursive thinking will be possible in normal adults due to the fact that adults are able to assert other viewpoints and distinguish and make decisions about the conditions under which others will think in similar or different ways than the person making the decision. Therefore, it is expected that normal adults will perform differently than the patterns of child recursive thinking suggested in the literature. Given that head-injured individuals have suffered damage to &he areas responsible for normal adult social interaction, they probably will be unable to think recursively. Since children are incapable of this level of thinking until the fiontal lobes mature, it is expected that adults whose fiontal areas are damaged may have difficulties in doing recursive thinking tasks.
Methods
Overview ofdesign
This investigation employed a static group comparison design. The two groups compared were non-head-injured, normal subjects and closed-head-injured subjects. All were compared on five levels of perspective taking: no recursions (Larry thinks . . .), mutual knowledge (Larry and Richard think . . .), one-loop recursions (Larry thinks Richard thinks . . .), two-loop recursions (Larry thinks Richard thinks Larry thinks . . .), and mutual knowledge with a single recursion (Larry and Richard think Susan thinks . . .). The dependent variable in this study is the number of error responses to multiple-choice questions about perspective of characters in each of the recursive thinking formats.
Subjects
Ten closed-head-injured subject and 10 control subjects were included in this study. Subjects in the two groups were matched on the basis of age and education. Participants in head injury and control groups were drawn from southeastern Pennsylvania.
The mean age of the closed-head-injured group was not significandy higher than the mean age of the control group (31 -9 and 27, respectively, T = - 1 -28, p = 0 -221). Education as measured by years in school did not significantly differ between the head injury and control groups (13, 13.3 respectively, T=0.37, p=0-713).
In the control group, current occupation was used for analysis and for the head- injury group; occupation pre-injury was recorded to understand pre-injury level of functioning in the head-injured group. In the control group, students represented the mist frequent occupational group (50%). followed by office workers (20%) and
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Cognitive factors in perspective taking 269
labourers, skilled labourers, and professionals followed (1 0% each). 'Labourers were the largest occupational group represented in the head-injury group (40%). followed by skilled labourers and office workers (20% each), with students and professionals representing the fewest participants (10% each).
Racial composition of the control group included 60% Caucasians, 30% Afro- American, and 10% Asian. In the head-injured group, Caucasians comprised 100% of the sample. The control group was composed of 60% males and 40% females. Within the head-injured group, 80% of the sample were represented by males and 20% by females.
In the head-injured group, car accident victims were represented in 90% of the group and explosion victims made up 10% of the group. Mean age at injury was 26.2 years (range 17-38). The mean time post-injury for th is group was 61 -2 months range 9-158 months). Forty per cent of the head-injury group lived independently (i.e. living at home either alone or with a relative) and 60% of the head-injury group were represented in supervised, group home living.
Subject selection procedure
Control subjects selected for this study were at least 18 years of age, had no previously known neurological illnesses, no previous psychiatric admissioddiagnoses, no periods of unconsciousness, spoke English as a first language, and read at or above the 6th grade reading level.
Closed-head-injured subjects selected for this study were at least 18 years of age, were at least 18 years of age at the time of the head injury, had no psychiatric admissionddiagnoses prior to the closed-head-injury , were at least 6 months post- injury, spoke English as a first language, and read at or above the 6th grade reading level.
Materials
A videotape o f a short scenario involving three characters was presented to each subject. The script content included exclusive interactions between pairs of characters in the form of a con game; however, the third character did not know of the interaction between the pair. This created some non-mutual knowledge states for which perspective-taking can be tested.
The content of the videotape involves an interaction between two men and one woman (Larry, Richard, and Susan). Larry and Susan are married. Larry has just lost another job and needs money to pay his bills. Susan asks him to leave until he can adequately support the household. Larry tries to get Richard (his friend) to lend him money. At first Richard is unwilling. Larry gets him to give him a blank cheque that Larry says he will cash and give all of the money to Richard to show Richard that he is trustworthy. Instead, Larry cashes the cheque for twice the amount of money. He gives Richard half. Larry takes the other half to Susan who knows nothing about where he got it. (A transcript of the videotape is available from the primary author.)
A probed-recall questionnaire was included in this study. This questionnaire tapped subjects' recall of the script. There were two sections of this questionnaire. A spontaneous recall section was used to determine if subjects could remember the contents of the videotape. The probed-recall section was for the purposes of ensuring
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270 J. Santoro and M. Spiers
that subjects were able to recognize enough of the story to participate in the perspective-taking questions. The script contained a few complicated interactions. This information was used in constructing the perspective-taking questions. If the subject did not understand these interactions then perspective-taking problems could be confounded with memory problems. Therefore, it was important that the subject demonstrate an understanding of the skit irrespective of perspective taking.
The Shipley Institute of Living Scale (Vocabulary and Abstraction Test) was presented to independently determine verbal and abstraction abilities. This was necessary to determine receptive speech capacity as well as to provide a measure of intellectual capacity rhat did not involve motor abilities.
Non-recursive questions were presented, devised by the experimenters pictorially as cartoon strips. These questions did not involve loops or recursions (only one thought bubble was placed above the characters’ heads). The questions were presented in the following manner. Larry thinks . . . (no recursions) or Larry and Richard think . . . (mutual knowledge).
Rerursive questions were also presented pictorially as in cartoon strips. These questions involved loops or recursions (thought bubbles embedded in other thought bubbles). In other words, a one-loop recursion represented a character thinking about another character’s thoughts (Larry thinks Richard thinks . . .). A two-loop recursion involved what one character thinks another character thinks the other character mentioned first is thinking (Larry thinks Richard thinks Larry thinks . . .).
Mutual knowledge with one-recursion questions were included. These represent what two characters believe a third character is thinking (Larry and Richard think Susan thinks . . .). These were also presented pictorially as a cartoon strip with thought bubbles.
All questions were derived from the actions by the characters in the skit. These were easily observed from the skit and pertained to actual occurrences within the skit which only some of.the characters know at any time. Each item was structured to include two egocentric responses reflecting the viewpoints of a single character in the skit, one correct perspective response reflecting the character’s point of view, and one perspective unrelated to the theme of the skit. One of the two egocentric responses reflected the viewpoint of a character that was present in the paired interaction, the other response reflected the viewpoint of a character not present during the paired interaction.
Procedure
Subjects were introduced to the experimenter and received a thorough explanation of the intent and procedures involved in this experiment.
After receiving this explanation, subjects were instructed as to their rights as delineated in the APA guidelines for research. Upon completion of the consent form, subjects were individually taken to testing rooms.
Subjects were asked to retell the skit as they remembered it. If certain details were not mentioned then, all multiple-choice questions were administered. If the five or more questions asked were incorrrect, the skit was reshown and the questionnaire was readministered up to a maximum of three times before a subject was discontinued for failure to meet the memory and comprehension criteria.
If 11 or more questions out of 15 were correct, then the recursive thinking or mutual knowledge questions were administered. One of two possible randomly
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Cognitive factors in perspective taking 271
ordered sets of items were presented to each subject. Subjects were trained in how to think about the cartoon bubble presentation for selecting the appropriate answers. Then test questions were asked.
After completion of the tasks, the Shipley Institute of Living Scale (Vocabulary and Abstraction Test) was administered as an independent measure of intelligence. Subjects were thanked for their participation and questions were answered.
Results
Group comparisons
Intelligence. Comparisons of control and head injury participants’ performances on the Shipley Institute for Living Scale Vocabulary, Abstraction, and Total score were made in order to achieve some estimate of level of intelligence differences. While the head injury and control groups did not reliably differ on Vocabulary (mean scores = 27 -6, 31), the head-injury group obtained a mean abstraction score of 22, which was significantly lower than the control group’s score of 31 -8 (T=3-4, p < 0.01). The two groups also differed on the summary score for the entire measure. The head-injury group mean total score of 48.6 was significantly lower than the control group’s mean score of 62.8 (T=3.337, p<O.Ol).
Memory. Both groups were compared on measures of recall given prior to the perspective-taking measure in order to ensure that the variance within the experimental measures did not result from inability to remember the skit. The first recall measure (i.e. the free-recall measure) did not significantly differ between the control and head- injury groups (4.8 items vs. 3.2 items, respectively, p = 0.258). On the second recall measure, the probed-recall measure, the control group’s mean of 14.6 items of information was significantly higher than the head-injury group’s mean performance of 12.2 (T=3*99, p=O*Ol).
Analysis of perspective-taking
Two separate repeated-measures ANOVAs were performed using the perspective- taking data (Table 1). Analysis designed to examine the validity of the hierarchical combination of Newman’s [16] concept of mutual knowledge and Miller et al.3 [14] concept of recursive thinking revealed a main effect for group (F = 10 - 82, p = 0 * 004) with no other main effects noted. Control group mean errors scores ranged from 3 -5 on no-recursion questions to 5 -8 on the double-loop recursion questions. In the head-injured group, mean error scores ranged from 6 on no recursion questions to 7 - 3 on single-loop recursion questions. No hierarchical relationship between Miller’s [ 141 and Newman’s [ 161 theories was implied.
The second analysis tests the hypothesis of Miller et al. [14] stating that with greater numbers of recursions more difficulty will be encountered by n o d subjects so that non-recursive questions have fewer errors than the questions with recursions, as well as the hypothesis that head-injured subjects will perform worse than control subjects on the recursive thinking questions. Analyses revealed significant main effects for both group (F = 7 - 46, p = 0.05) and recursive thinking question type (Wilks lambda + 0 7 1, F = 3 -49, p = 0.05), as well as an interaction between group and recursive thinking question type (Wilks lambda=0.66, F=3.46, p - 0 . 0 5 ) .
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Table 1. Mean error scores on no-recursion, mutual knowledge, single-loop recursion, double-loop recursion, and mutual knowledge with a single-loop recursion levels of social perspective-taking fm head-injured and
non-head-injured subjects
Group
Level Head-injured Non-head-injured No recursion 6-00 Mutual knowledge 6.20 Single-loop recursions 7.30 Double-loop recursions 6.50 Mutual knowledge with a single-loop 6-50
3*50* 4-40 4-70* 5.80 5.00
* p < 0.01.
In Table 1, mean scores are reported for each of the two groups on all of the perspective-taking questions with the control group performing better on the no- recursion and single-loop recursion questions. On the no-recursion questions the control group mean error score (3 -5) was significantly lower than the head-injury group mean error score (6) (T= 2 -91, p = 0.01). Likewise, the control group’s mean error score on the single-loop recursion questions of 4.7 was significantly lower than the head-injury group mean error score of 7.3 (T= -3.23, p=O-Ol). Head injury and control group mean error score did not reliably differ on mutual knowledge (6.2, 4-4), double-loop recursion (6 -5, 5 -8), and mutual knowledge with a single-loop recursion (6.5, 5).
Memory eflects on perspective-taking
Memory ability influence on perspective-taking performance was investigated because differences on the no recursion questions between the groups may be attributable to recall differences. The perspective-taking task required participants to remember the content of the skit for 1-11/2 hours (time required for the study). Given the significantly higher probed-recall performance by controls, it was necessary to deter- mine whether ability to recognize parts of the skit could explain the pattern found on perspective-taking tasks. In order to investigate the likelihood of recall influence on the differences found on no-recursion and single-loop recursion questions, those who showed high recall ability were compared to those showing low recall ability. A median split procedure was adopted to examine group membership of the subjects according to performance on the probed-recall task. Two recall groups were created via this procedure. The high-recall group consisted of individuals scoring greater than 13 correct out of 15 possible correct responses on the probed-recall task. The low- recall group consisted ofindividuals scoring less than or equal to 13 out of 15 possible points.
Both head-injured and control subjects were represented in these groups. Within head-injury group, 60% of the participants were represented in the low-recall group and 40% were represented in the high-recall group. In contrast, low-recall group membership was represented by 10% of the control group, whereas high-recall group membership was represented by 90% of the control group. Given the greater number of head-injured subjects in the low-recall group, the no-recursion questions mean error score would be expected to be significantly higher than in the high-recall group
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Cognitive factors in perspective taking 273
if recall were solely responsible for the variance demonstrated between the control and head-injury groups.
Post-hoc comparisons between the recall groups revealed a significantly lower mean number of errors on only one of the question types for the high-recall group (single- loop recursion. T= - 2.23, p = 0.04). No other significant differences were found on the no-recursion, mutual knowledge, double-loop recursion, and mutual knowledge with a single-loop recursion questions between high- and low-recall groups.
In the post-hoc analyses of probed-recall group membership influence on perspective-taking, only initial recall influences are considered. To consider the effects of long-term retention on perspective-taking, analyses of error types were made. Errors were classified as either errors of perspective or errors of content relationship. Errors of perspective refer to errors that represent perspectives of other characters in the story but not the correct perspective. For example, in the skit, Larry cheats Richard out of $100 but Richard does not know. If someone answered that Richard knows that Larry cheated him, it would be an incorrect perspective. Errors of content relationship refer to errors where no relationship to the story exists for that perspective. For example, if a participant answered that Larry knows Susan lied about Larry losing his job (an event that did not occur in the skit), then an error of content relationship would be scored.
In Table 2, percentages of errors of perspective and errors of content relationship are reported. None of the ratios of errors were at chance or random levels of guessing for either group. In the head-injury group, percentages of total errors ranged from 84.6% to 91 -9% for errors ofperspective and 8.1% to 12.9% for errors ofcontent relationship. Likewise, within the control group’s total number of errors, percentages of errors of content relationship from 2% to 16%.
The proportion of errors of perspective to errors of content relationship built into the task is 2:l. If random error were responsible for error patterns, then a 66% to
Table 2. Percentage of ewors of perspective and ewors of content relationship at each level of perspective- taking for head-injured and non-head-injured subjects
Group
Level Head-injured Non-head-injured
No recursion Perspective 90.0 84 Content 10.0 16
Mutual knowledge Perspective Content Single-loop recursions Perspective Content Double-loop recursions Perspective Content
87-1 12-9
91.9 8 - 1
84.6 15-4
98 2
85 15
85 15
Mutual knowledge with a single-loop recursion Perspective 87.6 98 Content 12.3 2
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a 33% errors of perspective to errors of content relationship would be expected. Random error patterns would imply forgetting and the use of guessing as a strategy. Errors for both the head-injury and control groups implied that guessing was not being used as a strategy for responding to questions. This suggested that perspective- taking differences and not memory capacity differences were responsible for the differences in recursive thinking abilities.
Discussion
Head-injured adults demonstrated more difficulty than non-head-injured adults in our perspective-taking task. Specifically, head-injured adults made more errors on single-loop recursion thinking tasks. Head-injured adults also made more errors on non-recursive thinking questions than non-head-injured adults, which was an unanticipated finding. Therefore, extensive efforts were put forth to understand why the head-injured adults in our study performed more poorly on tasks that apparently did not involve perspective-taking.
The findings of this study could be attributable to several factors. First, memory difficulties may have had an impact on non-recursive thinking task performance which would necessarily affect performance on other levels of perspective-taking. Two types of analyses were undertaken to demonstrate the effects of memory decay on perspective-taking. One analysis looked at the effects of low- and high-recall group membership on levels of perspective-taking performance. Differences were found between the groups on single-loop recursion questions, implying that memory may have an effect on perspective-taking performance on this task. Given that there were approximately equal numbers of head participants in both the high- and low-recall groups, it appears unlikely that memory difficulties were solely responsible for the differences in single-loop recursive thinking.
A second analysis of the data attempted to consider the effect of memory decay on pattern of task performance. As mentioned previously, two errors of perspective (incorrect perspectives) and one error of content (information not present in skit) were built into each level of perspective-taking. If a person were responding randomly, then an approximate ratio of 66% of the errors would be errors of perspective and 33% of the errors would be errors of content. None of the perspective to content error ratios for head-injured or non-head-injux'ed adults approximated random response profiles. This supports the premise that although there were some memory difficulties, these did not seem to significantly impact upon perspective-taking.
Another factor in this study to be considered was the hierarchy of responses. At first glance it appeared that within the non-head-injured subjects there was a hierarchy of level of difficulty according to the number of recursions in the task. Subsequent data analyses statistically revealed no such hierarchy. Further study regarding normal adult perspective-taking abilities is indicated with systematic comparisons between children, adolescents, and adults to validate Miller et al. [14], Selman [15], and Newman's [ 161 findings.
Third, differences between head-injured adult performance and non-head-injured adult performance can be attributed to the head trauma. Head-injured adults did not significantly differ from non-head-injured adults in terms of vocabulary, which is crystallized function typically not affected by brain injury. This finding suggested that both groups were cognitively functioning at approximately the same level prior to the accident for the brain-injured group.
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Cognitive factors in perspective taking 275
These groups did, however, differ in terms of their verbal abstraction abilities which is typically found post-head trauma. As mentioned previously, Golden [13] suggested that when tertiary second functional unit development occurs, children are able to think logically and abstractly about information. Head-injured adults demonstrated more difficulty in this area than non-head-injured adults, suggesting that not only were frontal areas affected by their injuries but also posterior brain areas as well. The mechanism of head injury necessarily globally affects brain tissue, which is consistent with these abstraction difficulties.
Although it was thought that head-injured adults would not differ from non-head- injured adults’ performances on non-recursive questions, head-injured individuals demonstrated more difficulties with even non-recursive questions. Despite accuracy in recall of content of the skit, head-injured participants were unable to separate what they knew from what was known by each of the characters individually. Impaired abstraction and impulse control resulted in the head-injured patients’ inability to consider any viewpoint but their own.
These low-level perspective-taking deficits cause more difficulties in relating to others. Without the ability to see the effects of one’s behaviour on another, behaviours necessarily impinge on another’s well-being. Feedback about the social unacceptabaty of head-injured behaviours does not result in modification of behaviour because the head-injured person does not understand what was offensive. Understanding that behaviours have offended another requires perspective-taking. Since the feedback is meaningless, social withdrawal and isolation result. More dif5culties relating to family, friends, and employers are subsequently seen.
Therefore, future directions for research would include further standardization and age norming to eliminate the effects of attention and memory, as well as to provide age-level equivalents for social understanding. Second, more study is indicated to investigate the relationship of these perspective-taking tasks to neuropsychological indicators in order to enhance the predictive ability of traditional testing for level of social hnctioning. Finally, since the goal of this study was to pilot a social cognitive task to look at the process of perspective-taking, further research is necessary to develop treatment recommendations, methodological changes in therapeutic inter- ventions, family education, and environmental alterations. The implications of this study suggest that patients might benefit from changes in current modes of treatment in order to enhance their quality of life.
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