Br. J . SOC. clin. Psychol. (1975), 14, pp. 63-71 Printed in Great Britain
A Proposed Basis for Delusion Formation within an Information-Processing Model of Paranoid Development
BY A L F R E D B. H E I L B R U N ,
JR.
Department of Psychology, Emory University, Atlanta, Georgia A developmental model for paranoid behaviour is proposed within a broader theory of schizophrenic development. T h e model stipulates that given exposure to sustained aversive maternal control and a maternal communication style which is subtle and devious, the child comes to adapt with approach, stratagem-based behaviours and heightened vigilance for evaluative information (i.e. open adaptive style). The model, already supported empirically at several points, postulates that the delusion serves to organize an overextended and disorganized information-processing system for the person and generates its reinforcement from reduction of the anxiety associated with thought disorganization. T h e present study tested an aspect of this postulate. I t was predicted that late-adolescent males who had an open style of adapting to experienced aversive maternal control would find the organization of disorganized evaluative cues uniquely reinforcing. Subjects were presented with an anagrams task made up of scrambled words which they were told came from a poll of mothers asked to evaluate their college-age sons. This task was followed by the individual tachistoscopic and slightly unfocused presentation of a longer series of words, again described as maternal evaluative terms. T h e longer series comprised the words used in the anagrams task and an equal number which were not. Reinforcement value of proper ordering of disorganized cues was inferred from the subject’s heightened ability to detect previously solved anagram terms, indicating stronger learning of these terms upon prior solution. Males identified as open-style adapters were far morc cognizant of words which they had previously ordered than other child-rearing groups, as predicted.
While there is considerable agreement regarding the defining behavioural components of paranoia, far less agreement has been reached regarding the developmental antecedents to this disorder. What little evidence exists regarding social antecedents has been generated largely from clinical observation or study. The precision of laboratory investigation has not been systematically brought to bear upon the problem of identifying the social origins of paranoid behaviour or the specific behavioural properties which subserve this syndrome. Attempts to account for the fixed, systematic and unrealistic modes of thinking which are the hallmark of paranoid behaviour range from relatively circumscribed hypotheses to those which encompass the long-range developmental conditions which determine their occurrence. Examples of the former would be Freud’s (1912) account of paranoia in terms of the projection of unconscious homosexual wishes or the proposal that paranoid delusions may be triggered off by exaggerated cases of constipation (Alexander & Flagg, 1965). Others have presented more extended accounts of paranoid development which stress early difficulties in social relationships which result in deficient role-taking ability (White & Watt, 1973), defensive assertions of superiority generalized from the home situation (Coleman, 1972), or failure to develop interpersonal trust (Cameron, 1963). 63
64
A. B. HEILBRUN, JR.
In contrast to these clinically derived hypotheses, Heilbrun (1973a) has proposed a social developmental model for paranoid behaviour based upon a series of experiments conducted with non-clinical samples of male late-adolescents. The strategy of this research programme has been to identify as many behaviours as possible which could contribute to paranoid behaviour and to demonstrate that adolescents having a specified maternal child-rearing experience will be uniquely characterized by those behaviours. This research strategy assumes a continuity between the subclinical manifestations of paranoid behaviour observed in normals (e.g. oversensitivity, suspiciousness, premature conclusions) and the more blatant, often bizarre, paranoid states demonstrated by neurotic and psychotic patients. Accepting the assumption of continuity justifies the study of non-clinical populations as a way of understanding the origins of more serious psychopathological states. The more general theory out of which the paranoid development model evolved, fully explicated elsewhere (Heilbrun, 1973a), proposes that when the son experiences sustained control and rejection by the mother, he learns to adapt to the aversive qualities of the relationship in one of two general ways. If the mother’s style of communication is clear and direct, he is likely to adopt defensive avoidance or withdrawal behaviours in relating to her and, through generalization, to other sources of social evaluation. Self-protective aspects of adaptation also would include a guarded perceptual response to evaluative cues. This is described as the closed adaptive style. The second mode of adaptation, learned when the mother’s communication of control and rejection cues is unclear and devious, involves an approach orientation towards the mother instigated by the need to clarify or modify directive and evaL ative meaning. Generalization to other sources of social evaluation not only establishes a broad sensitivity to interpersonal cues but also facilitates strategies directed towards modifying negative evaluation and eliciting signs of positive regard. This style of adaptation to aversive maternal control involves a heightened perceptual sensitivity to evaluative cues, particularly those having a negative meaning, and is termed the open adaptive style. Reasoning deductively from the broader theory and inductively from research evidence has led to the proposal that the developmental dynamics of the open adaptive style predispose the person to paranoid behaviour (Heilbrun, 1973 a). The postulates of the model and the supporting evidence accumulated to date are as follows: ( I ) The general effect of the aversive-maternal-control experience is to produce low self-esteem and a sensitivity to social evaluation (Heilbrun et al., 1967; Heilbrun, 1970; Heilbrun & Norbert, 1970). (2) Aversive-control mothers who are more subtle and devious in their communication style facilitate a perceptual orientation in their sons involving vigilance to evaluative meaning and the imposition of meaning in the absence of clarity -. the open adaptive style (Heilbrun, 1 9 7 2 ~ ) . (3) Generalization of these perceptual-cognitive qualities predisposes the openstyle adapter to broad scanning of external cues in his social environment (Heilbrun, 1971) and narrow internal scanning of symbolic cues (Heilbrun, 1972b).
A Developmental Model of Paranoia
65
Attention is primarily deployed to external events rather than cognitive processing of alternative meanings. (4) The open-style child’s sensitivity to social evaluation and his tendency to impose meaning on unclear communications combine to make him intolerant of ambiguity in the meaning of external cues (Heilbrun, 1972~). ( 5 ) The open-style adapter maintains a constant interpersonal frame of reference in which his meaning to others is at issue. His perceptual vigilance to evaluative cues continually confronts him with threats to his vulnerable self-esteem, largely because of his selective perception of negative evaluative cues from among alternatives (Heilbrun, 1973 b). When threatened, he will turn negative evaluation back upon his social environment by means of denial and projection (Heilbrun, 1g72d). (6) The characteristic and ineffective ways in which the open-style offspring acquires and processes evaluative information (e.g. broad scanning, selective perception, premature attribution of meaning, limited consideration of alternative meanings, projection of erroneous information) combine to create episodes of disorganized thinking generated by information overload and erroneous judgement. (7) Thought disorganization is aversive to the individual who attempts to reduce its anxiety-provoking effect and avoid its recurrence by adopting false but simplifying schemas (i.e. delusions) which organize the information. The fixed ideation of the open-style adapter (Heilbrun & Norbert, 1972) maintains its strength as an instrumental response because it is reinforced by the avoidance of thought disorganization. Many of these postulates correspond to observations or research evidence based upon clinical paranoid samples. Perhaps the two points where the model presented departs most radically is in the proposal that the mother-son relationship represents an important social-learning origin for paranoid behaviour and in the proposed functional significance of the delusion in paranoia. It is with the latter postulation that the present study is concerned. Clinical theorists commonly assume that the delusion serves the function of protecting the paranoid’s vulnerable sense of worth by giving him a rationale for failure other than his own limitations. The delusion, furthermore, is viewed as following directly from the denial and projection of unfavourable evaluative information back upon the paranoid’s social environment. In reinforcement terms, this line of reasoning would most likely assume that the strength of delusional responses stems from the reduction and avoidance of anxiety they provide when self-esteem is jeopardized. This explanation does present one problem, however, in that the paranoid’s misinterpretations of reality (e.g. ideas of reference, persecutory delusions) often generate as much anxiety as they are supposed to reduce. Thus it seems profitable to seek additional sources of anxiety reduction to understand the tenacity of delusional thinking. The current model amounts to an information acquisition and processing interpretation of paranoid behaviour. The open-style male is distinguished by his broad external scanning for evaluative cues and his selective attention to unfavourable evaluative meanings ; both attributes influence the manner in which information is acquired from the environment. Furthermore, open-style adaptation involves 5
SCP I
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A. B. HEILBRUN, JR.
a distinctive pattern of information processing - premature attribution of meaning, limited consideration of alternative meanings, and denial and projection of meaning. In keeping with an information model, our hypothesis for delusion formation also holds that the delusion is reinforced by its anxiety-reducing properties but stipulates an additional source of anxiety. The person has overloaded his capacity to process information and the delusion reinstitutes and maintains order in thinking in place of anxiety-arousing disorganization. This delusion-formation hypothesis is similar to an earlier proposal by Cameron (I~sI), who distinguished two stages of delusion formation. The hypervigilant stage leads the individual to’ view nearly all information as related to certain dominant hypotheses. The second stage is one in which the individual disregards information which is not congruent with his delusional system and by doing so avoids information overload. The present delusion-formation proposal can be recognized as a way of understanding the shift from the first to the second stage. It can be noted that several other clinical investigators have emphasized the importance of problems in information processing, especially with schizophrenics. Venables (1964)has described ‘input dysfunction’ as a part of the pathological process. He proposes that chronic and process patients experience hyperarousal and thus restrict attention to external stimulation. Acute and reactive patients, in contrast, are characterized by hypoarousal associated with a deficit in selective and inhibitory functions. Flooding of the information-processing system with exteroceptive information results. A clinical investigation of acute schizophrenics by McGhie & Chapman (1961) led them to hypothesize a breakdown in the selectiveinhibitory function of attention which floods consciousness with an undifferentiated mass of incoming information. Silverman (1964)pointed to the broad scanning of exteroceptive stimulation characteristic of paranoid schizophrenics. T h e present investigation sought to test one aspect of the delusion-formation postulate outlined above. If the postulation were correct, it should be possible to demonstrate that the proper ordering of disorganized symbolic cues is uniquely reinforcing to late-adolescent males who have adopted an open style of adaptation to aversive maternal control. METHOD Subjects
Seventy-five white male undergraduates at Emory University participated in this experiment during the autumn and winter quarters, 1972-73. They were obtained as volunteers from the subject pool maintained by the entry psychology courses. The mean age of the subjects was I 8.5 years. Emory undergraduates are predominantly from middle-class social backgrounds. Measures of maternal experience Maternal child-rearing control. Perceived maternal child-rearing behaviours were measured by means of the subject’s ratings on two questionnaires. The maternal form of the Parent Attitude Research Instrument (Schaefer & Bell, 1958) was administered to the subject with instructions to complete it as his mother would. A major factor-analytic cluster of 16 ‘authoritarian-control’scales among the 23 total scales has been identified by Schaefer & Bell (1955) and Zuckerman et al. (1958). Each scale comprised five items, each item offering
A Developmental Model of Paranoia
67 disagree ’
response options ranging from ‘strongly agree ’ (score = 4) down to ‘ strongly (score = I). The cumulative score over these 16 scales defined attributed maternal control. Maternal child-rearing nurturance. The Parent-Child Interaction Rating Scales (Heilbrun, I 964) were used to measure perceived maternal nurturance. This questionnaire includes eight related modes of parental nurturance with ratings obtained on five-point, descriptively anchored scales. Cumulative scores defined perceived maternal nurturance. Both the Parent Attitude Research Instrument and the Parent-Child Interaction Rating Scales, employed as measures of perceived child-rearing experience, have proven their heuristic valug in over 40 published investigations (reviewed in Heilbrun, 1973 a).
Thought disorganization analogue T h e symbolic disorganization-ordering-reinforcement sequence was simulated by first presenting the subject with a series of evaluative adjectives with the letters scrambled SO as to form an anagrams task. A pilot study using a mixed sample of 20 male and female Emory students was used to calibrate the difficulty of the task by varying the time allotted for solution of the 33 anagrams from 10 to 20 min. T h e zo-min. period resulted in an average of 13.9 correct solutions and was adopted as the level of task difficulty for the main experiment. T h e second task required of all subjects was a word-recognition procedure within which 66 behavioural adjectives were individually presented, slightly out of focus, for IOO msec. each by means of a Kodak Carousel slide projector. These 66 words were originally chosen from the Adjective Check List (Gough & Heilbrun, 1965) and included zz judged to reflect favourably upon the person, zz to reflect unfavourably and zz of neutral evaluative connotation. Half of these adjectives ( I I favourable-neutral-unfavourable triads) were used for the anagrams task. The subject was instructed to identify as many of the briefly exposed words as possible and was given four practice words prior to beginning.
Procedure Questionnaire administration. Questionnaires were administered in small groups, each subject being recalled individually for the laboratory session within a few weeks. T h e same female experimenter conducted both sessions. Stroop-tape procedure. The subject was presented the Stroop-tape task when he returned for the individual session, the basis for inferring open or closed styles of adaption to aversive maternal control. This involved the administration of the Stroop Colour-Naming Task (Stroop, 1935) in which the subject is required to name the colour in which each of 144 nominal colour words is printed. T h e words are never printed in the colour which they name (c.g. the word ‘blue’ may be printed in green ink). This procedure was devised to be susceptible to response interference, since it requires a reversal of the habituated reading response. After a baseline of performance had been established for the subject, a second form of the Stroop was administered. This time the subject had to perform while listening through earphones to a tape-recorded mother-son interaction. The taped dialogue was recorded by professional actors from a prepared script and represents a hostile and controlling tirade directed by a mother towards her son (Olsen, 1965). The ability of the subject to ignore the task-irrelevant aversive-maternal-control cues, after being instructed to do so, is given by his error score on Stroop no. z relative to his baseline score on Stroop no. I . Relatively disrupted performance on Stroop no. 2, indicating an inability to fend off the task-irrelevant cues, represents the operational definition of the vigilant open-adaptive style (for the maternal high control-low nurturance male) or the disrupted control group (for males having other than a high control-low nurturance maternal experience). Relatively nondisrupted Stroop no. z performance, indicating an ability to ignore the task-irrelevant maternal cues, defines the defended closed adaptive style or its non-disrupted control group, again depending upon the presence or absence of the aversive-maternal-control experience. The Stroop-tape procedure and the child-rearing questionnaires have been used as a standardized battery since 1968, thereby generating almost identically defined groups in each investigation. Accordingly, the results from all adaptive-style studies are directly comparable. 5-2
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A. B. HEILBRUN, JR.
Reinforcement value of reducing thought confusion. T h e analogue condition for testing the reinforcement value of alleviating confused or disorganized thinking involved two phases. First, the subject (after completing the Stroop-tape procedure) was told that we had taken several of the most frequently used words from a poll of mothers in which they had been asked to describe their college-age sons. This bogus information, intended to induce an evaluative set in the subject, has been used in several previous adaptive-style studies with apparent success. The subject was further informed that the evaluative words would be presented to him in a jumbled form and that he should order as many of these maternal evaluative terms in proper form as he could in the time allowed. Following the zo-min. anagrams task, the subject was told that he now would be shown the longer list of frequently used evaluative terms obtained from the pool of mothers. This time, however, the words were to be only briefly exposed on the screen, and it was to be his job to identify as many of these adjectives as possible. I t was explained that the words on the anagrams task would be among those shown. Four practice words were provided to familiarize the subject with the procedure, and these were followed by 66 test words. Completion of the tachistoscopic task marked the end of the experiment.
RESULTS
Definitions of the experimental groups Mean scores taken from Emory norms for males were used as cutting scores to define high perceived control (Parent Attitude Research Instrument control score > 192) and low perceived nurturance (Parent-Child Interaction Rating Scales score < 33). Sixteen males were defined as high control-low nurturance, whereas the remaining 59 males (high control-high nurturance, low control-high nurturance, low control-low nurturance) were combined into a general reference group to serve as controls for child-rearing experience." Assignment to open-style or closed-style groups for the high control-low nurturance subjects or to disrupted or non-disrupted control groups for the general reference group subjects was based upon a median split of the Stroop no. I minus Stroop no. 2 difference score for all 75 subjects in the study. Failure to improve on Stroop no. 2 defined disruption ( n = 37), whereas improvement on Stroop no. 2 despite the distracting cues defined non-disruption ( n = 38). Definition and analysis of reinforcement score The definition of a reinforcement score in this investigation is based upon the following two assumptions: (I) the greater the reinforcement value of organizing a previously disorganized evaluative stimulus, the greater the learning of that organized stimulus; (2) the more highly learned the stimulus, the more readily recognized it should be when subsequently presented in ambiguous form. Both assumptions appear to be readily defensible. Each subject was assigned two scores reflecting his accuracy of perception. One represented the percentage of solved anagrams which had been correctly identified in the tachistoscopic procedure, and the second represented the percentage of words
* Analysis of variance indicated that these three child-rearing groups, separated by disruption level, did not differ from one another on the major dependent variable in this expcriment.
A Developmental Model of Paranoia
69
Table I . Reinforcement value of reduction in evaluative cue disorganizationfor lateadolescent males varying in maternal child-rearing experience and adaptive style Maternal child-rearing experience L-
7-
High control-Low nurturance
7
General reference group
Disrupted (Open style of adaptation) (n = 7)
Non-disrupted (Closed style of adaptation) (n = 9)
Score*
Mean
S.D.
Mean
S.D.
Mean
S.D.
Mean
s.~.
Anagrams Reinforcemcnt
13'14 39'19
6.54
10'22
3'09
13'07
18-20
18.40
6.05 7'72
IZ.45 22'45
13.33
14-64
16.61
Disrupted controls (n = 30)
Non-disrupted controls (n = 29)
5'01
* Anagrams score = number correctly solved. Reinforcement score = percentage correctly solved word anagrams subsequently detected minus percentage unfamiliar words subsequently detected. to which the subject had not been previously exposed in this experiment which were subsequently identified correctly when briefly presented. The latter set of words included the anagrams not correctly solved plus the 33 words not included in the anagrams task. The reinforcement score was derived by subtracting the latter percentage from the former, thereby imposing an intra-individual control for perceptual acuity. Derived in this way, a high plus score means that the person was far more able to recognize ambiguously presented evaluative words which he had previously unscrambled than a person with a low plus or a minus score, independent of his general perceptual acuity. Table I includes data relevant to the reinforcement scores for the experimental groups. Preliminary consideration of the numbers of anagrams correctly solved (row I, Table I), using a two-factor factorial analysis of variance for unequal cell frequencies (Winer, 1962), indicated no significant effect of child rearing (F = 1.24; d.f. = I , 7 1 ; P > o - ~ o )disruption , level (F < I'OO), nor any interaction effect (F < 1-00>. Accordingly, all four child-rearing x disruption level groups started from the same numerical base of correctly solved anagrams in determining the reinforcement score. Statistical evaluation of reinforcement score means by the same type of factorial analysis of variance as used with the anagrams score revealed a significant main effect of child-rearing (F = 4-32; d.f. = I , 71; P < 0.05) and of disruption level (F = 6.64; d.f. = I , 71; P < 0.025). Of greater importance, however, was the finding of a significant interaction effect (F = 13.72; d.f. = I , 71; P < 0.001) requiring inspection of the critical simple effects. The reinforcement score for the open-style males (39.19) was significantly greater than that found for either the closed-style group (16.61) or the disrupted control group (18.40); F values were 20.62 (P < 0.001for I, 71 d.f.) and 16.73 (P < 0.001for I , 71 d.f.), respectively. Thus, the predicted greater reinforcement value of removing cue disorganization for open-style males was strongly supported.
70
A. B. H E I L B R U N J R,.
Control comparison of the closed-style group (16.61)with its non-disrupted control (22.45) proved non-significant (F = 1.28; d.f. = I, 71; P > 0.20) as did the comparison of the two control groups with each other (F < 1.00).
DISCUSSION
Since the postulate under investigation in this experiment is a complex one, it is important to consider what has been tested (and supported) by the present results and what has not. The postulate states that disorganization in thinking occurs when extensive, biased and erroneous intake of information, especially of an evaluative nature, overextends the processing capacities of the open-style adapter. Such disorganization is aversive, and he reduces his distress by organizing the store of information by means of simplifying schemas encompassed within a delusional system. Finally, the delusion remains fixed because of its anxiety-avoidance properties. T h e evidence in support of the open-style male’s extensive scanning of information, his biased perception of information, and the susceptibility to erroneous interpretation of ambiguous information has been cited earlier in this paper. Similarly, his limited effectiveness in dealing with alternative meanings and his more fixed ideation in the face of contradictory evidence have been documented. T h e present evidence points toward the greater reinforcement value inherent in reducing disorganization in evaluative cues for the open-style adapter. This finding is important to the information-processing model of paranoid development, since it offers a necessary precondition to subsequent investigation of further model assumptions. Yet to be tested are the contention that the delusion serves a cognitive organizing function from which it derives its reinforcement and that the source of reinforcement which follows cognitive organization of information is the reduction of anxiety generated by disorganized thought. The model for paranoid development presented in this paper is not proposed as a singular explanation of how paranoid conditions may arise. The question of the importance of this social-learning explanation relative to other proposals remains to be answered. In fact, we would speculate that the present model would have greater applicability to the paranoid conditions associated with reactive schizophrenia than those associated with process schizophrenia. This conclusion derives from the closer parallels between reactive schizophrenic behaviour and those postulated by the model. It may be recalled, too, that Venables (1964) considered reactive schizophrenics to be susceptible to flooding of the information-processing system. We might look for the formation of delusions in process schizophrenics to be more related to the absence of informational input from the external environment. REFERENCES ALEXANDER, F. & FLAGC,G. W. (1965). The psychosomatic approach. In B. B. Wolman (ed.), Handbook of Clinical Psychology. New York : McGraw-Hill. CAMERON, N . (1951). Perceptual organization and behaviour pathology. In R. R. Blake & G. V. Ramsey (eds.), Perception: an Approach to Personality. New York: Ronald Press.
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CAMERON, N. (1963). Personality Development and Psychopathology: a Dynamic Approach. Boston: Houghton Mifflin. J. C. (1972). Abnormal Psychology and Modern Life. Glenview, 111.: Scott, COLEMAN, Foresman. FREUD, S. (1912).Psychoanalytic notcs on an autobiographical account of a case of paranoia. Standard Edition, vol. 12. London: Hogarth Press, 1958. Gowcir, H. G. & HEILBRUN, A. B. (1965).Manualfor the Adjective Check List and the Need Scalesfor the ACL. Palo Alto, Calif. : Consulting Psychologists Press. HEILBRUN, A. B. (1964).Parent model attributes, nurturant reinforcement and consistency of behaviour in adolescents. Child Dev. 35, 151-167. HEILBRUN, A. B. (1970). Perceived maternal child-rearing expcrience and the effects of vicarious and direct reinforcement on malcs. Child Dev. 41,253-262. HEILBRIJN, A. B. (1971).Style of adaptation to pcrccived aversive maternal stimulation and sclective attention to evaluative cues. J. abnorni. SOC. Psychol. 77, 340-344. HEILBRUN, A. B. ( 1 9 7 2 ~ )Distinctiveness . of maternal control: a further link in a theory of schizophrenic development. J. nerw. ment. Dis. 154,49-60. HEILBRUN, A. B. (19726). Style of adaptation to perceived aversive maternal control and internal scanning behaviour. J. consult. clin. Psychol. 39, 15-21. HEILBRUN, A. B. ( 1 9 7 2 ~ )Tolerance . for ambiguity in late-adolescent males: implications for a developmental model of paranoid behaviour. Dew. Psychol. 7, 288-294. HEILBRUN, A. B. (1972d). Defensive projection in late adolescents: implications for a developmental model of paranoid behaviour. Child. Dev. 43,880-891. HEILBIIUN, A. B. (1973 a). Aversive Maternal Control: a Theory of Schizophrenic Development. New York: Wiley. HEILBIIUN, A. B. (1973b). Adaptation to aversive maternal control and perception of simultencously presented evaluative cues: further test of a dcvelopmental model of paranoid behaviour. J. consult. clin. Psychol. 41, 301-307. HEILBRUN, A. H., HARRELL, S. N. & GILLARD, B. J. (1967).Perceived maternal child-rearing patterns and effects of social nonreaction upon achievement motivation. Child Dev. 38, 267-281. HEILBRUN, A. B. & NORBERT, N. (1970). Maternal child-rearing experience and sclfreinforccmcnt effectiveness. Dev. Psychol. 3, 81-87. HEILBRUN, A. B. & NORBERT, N. (1972).Style of adaptation to avcrsive maternal control and paranoid behaviour. J. genet. Psychol. 120,145-153. MCGHIE,A. & CHAPMAN, J. ( 1 9 6 1 ) .Disorders of attention and perception of early schizophrenia. Br. J. med. Psychol. 34,103-1 17. OLSEN,S. P. (1965). Response intcrfercnce as a function of social evaluation and maternal child-rearing expcricnce. (Unpublished doctoral dissertation, University of Iowa.) SCHAEFER, E. S. & BELL, R. Q. (1955). Parent Attitudc Research Instrument (PARI): Normative data. (Unpublished manuscript, Library, National Institutes of Hcalth, Bcthcsda, Maryland.) SCHAEFER, E. S. & BELL,R. Q. (1958).Devclopment of a Parent Attitude Research Instrumcnt. Child Dev. 29, 339-361. SILVERMAN, J. (1964).Scanning-control mechanism and ' cognitive filtering' in paranoid and non-paranoid schizophrenia. J. consult. Psychol. 28, 385-393. STROOP, J. R. (1935). Studies of interference in serial verbal reactions. J. exp. Psychol. 18, 643-672. VENAHLES, P. H.(1964). Input dysfunction in schizophrenia. In B. A. Maher (ed.), Progress in Experimental Personality Research. New York : Academic Press. WHITE,R. W . & WATT,N. F. (1973). T h e Abnormal Personality. New York: Ronald Press. WINER,B. J. (1962). Statistical Principles in Experimental Design. New York: McGraw-Hill. ZUCKERMAN, M., RIBBACK, B., MONASHKIN, I. & NORTON,J. A. (1958). Normative data and factor analysis on the Parent Attitude Research Instrument. J. consult. Psychol. 22, 165-171.
Manuscript received 20 September 1973
A Proposed Basis for Delusion Formation within an Information-Processing Model of Paranoid Development
BY A L F R E D B. H E I L B R U N ,
JR.
Department of Psychology, Emory University, Atlanta, Georgia A developmental model for paranoid behaviour is proposed within a broader theory of schizophrenic development. T h e model stipulates that given exposure to sustained aversive maternal control and a maternal communication style which is subtle and devious, the child comes to adapt with approach, stratagem-based behaviours and heightened vigilance for evaluative information (i.e. open adaptive style). The model, already supported empirically at several points, postulates that the delusion serves to organize an overextended and disorganized information-processing system for the person and generates its reinforcement from reduction of the anxiety associated with thought disorganization. T h e present study tested an aspect of this postulate. I t was predicted that late-adolescent males who had an open style of adapting to experienced aversive maternal control would find the organization of disorganized evaluative cues uniquely reinforcing. Subjects were presented with an anagrams task made up of scrambled words which they were told came from a poll of mothers asked to evaluate their college-age sons. This task was followed by the individual tachistoscopic and slightly unfocused presentation of a longer series of words, again described as maternal evaluative terms. T h e longer series comprised the words used in the anagrams task and an equal number which were not. Reinforcement value of proper ordering of disorganized cues was inferred from the subject’s heightened ability to detect previously solved anagram terms, indicating stronger learning of these terms upon prior solution. Males identified as open-style adapters were far morc cognizant of words which they had previously ordered than other child-rearing groups, as predicted.
While there is considerable agreement regarding the defining behavioural components of paranoia, far less agreement has been reached regarding the developmental antecedents to this disorder. What little evidence exists regarding social antecedents has been generated largely from clinical observation or study. The precision of laboratory investigation has not been systematically brought to bear upon the problem of identifying the social origins of paranoid behaviour or the specific behavioural properties which subserve this syndrome. Attempts to account for the fixed, systematic and unrealistic modes of thinking which are the hallmark of paranoid behaviour range from relatively circumscribed hypotheses to those which encompass the long-range developmental conditions which determine their occurrence. Examples of the former would be Freud’s (1912) account of paranoia in terms of the projection of unconscious homosexual wishes or the proposal that paranoid delusions may be triggered off by exaggerated cases of constipation (Alexander & Flagg, 1965). Others have presented more extended accounts of paranoid development which stress early difficulties in social relationships which result in deficient role-taking ability (White & Watt, 1973), defensive assertions of superiority generalized from the home situation (Coleman, 1972), or failure to develop interpersonal trust (Cameron, 1963). 63
64
A. B. HEILBRUN, JR.
In contrast to these clinically derived hypotheses, Heilbrun (1973a) has proposed a social developmental model for paranoid behaviour based upon a series of experiments conducted with non-clinical samples of male late-adolescents. The strategy of this research programme has been to identify as many behaviours as possible which could contribute to paranoid behaviour and to demonstrate that adolescents having a specified maternal child-rearing experience will be uniquely characterized by those behaviours. This research strategy assumes a continuity between the subclinical manifestations of paranoid behaviour observed in normals (e.g. oversensitivity, suspiciousness, premature conclusions) and the more blatant, often bizarre, paranoid states demonstrated by neurotic and psychotic patients. Accepting the assumption of continuity justifies the study of non-clinical populations as a way of understanding the origins of more serious psychopathological states. The more general theory out of which the paranoid development model evolved, fully explicated elsewhere (Heilbrun, 1973a), proposes that when the son experiences sustained control and rejection by the mother, he learns to adapt to the aversive qualities of the relationship in one of two general ways. If the mother’s style of communication is clear and direct, he is likely to adopt defensive avoidance or withdrawal behaviours in relating to her and, through generalization, to other sources of social evaluation. Self-protective aspects of adaptation also would include a guarded perceptual response to evaluative cues. This is described as the closed adaptive style. The second mode of adaptation, learned when the mother’s communication of control and rejection cues is unclear and devious, involves an approach orientation towards the mother instigated by the need to clarify or modify directive and evaL ative meaning. Generalization to other sources of social evaluation not only establishes a broad sensitivity to interpersonal cues but also facilitates strategies directed towards modifying negative evaluation and eliciting signs of positive regard. This style of adaptation to aversive maternal control involves a heightened perceptual sensitivity to evaluative cues, particularly those having a negative meaning, and is termed the open adaptive style. Reasoning deductively from the broader theory and inductively from research evidence has led to the proposal that the developmental dynamics of the open adaptive style predispose the person to paranoid behaviour (Heilbrun, 1973 a). The postulates of the model and the supporting evidence accumulated to date are as follows: ( I ) The general effect of the aversive-maternal-control experience is to produce low self-esteem and a sensitivity to social evaluation (Heilbrun et al., 1967; Heilbrun, 1970; Heilbrun & Norbert, 1970). (2) Aversive-control mothers who are more subtle and devious in their communication style facilitate a perceptual orientation in their sons involving vigilance to evaluative meaning and the imposition of meaning in the absence of clarity -. the open adaptive style (Heilbrun, 1 9 7 2 ~ ) . (3) Generalization of these perceptual-cognitive qualities predisposes the openstyle adapter to broad scanning of external cues in his social environment (Heilbrun, 1971) and narrow internal scanning of symbolic cues (Heilbrun, 1972b).
A Developmental Model of Paranoia
65
Attention is primarily deployed to external events rather than cognitive processing of alternative meanings. (4) The open-style child’s sensitivity to social evaluation and his tendency to impose meaning on unclear communications combine to make him intolerant of ambiguity in the meaning of external cues (Heilbrun, 1972~). ( 5 ) The open-style adapter maintains a constant interpersonal frame of reference in which his meaning to others is at issue. His perceptual vigilance to evaluative cues continually confronts him with threats to his vulnerable self-esteem, largely because of his selective perception of negative evaluative cues from among alternatives (Heilbrun, 1973 b). When threatened, he will turn negative evaluation back upon his social environment by means of denial and projection (Heilbrun, 1g72d). (6) The characteristic and ineffective ways in which the open-style offspring acquires and processes evaluative information (e.g. broad scanning, selective perception, premature attribution of meaning, limited consideration of alternative meanings, projection of erroneous information) combine to create episodes of disorganized thinking generated by information overload and erroneous judgement. (7) Thought disorganization is aversive to the individual who attempts to reduce its anxiety-provoking effect and avoid its recurrence by adopting false but simplifying schemas (i.e. delusions) which organize the information. The fixed ideation of the open-style adapter (Heilbrun & Norbert, 1972) maintains its strength as an instrumental response because it is reinforced by the avoidance of thought disorganization. Many of these postulates correspond to observations or research evidence based upon clinical paranoid samples. Perhaps the two points where the model presented departs most radically is in the proposal that the mother-son relationship represents an important social-learning origin for paranoid behaviour and in the proposed functional significance of the delusion in paranoia. It is with the latter postulation that the present study is concerned. Clinical theorists commonly assume that the delusion serves the function of protecting the paranoid’s vulnerable sense of worth by giving him a rationale for failure other than his own limitations. The delusion, furthermore, is viewed as following directly from the denial and projection of unfavourable evaluative information back upon the paranoid’s social environment. In reinforcement terms, this line of reasoning would most likely assume that the strength of delusional responses stems from the reduction and avoidance of anxiety they provide when self-esteem is jeopardized. This explanation does present one problem, however, in that the paranoid’s misinterpretations of reality (e.g. ideas of reference, persecutory delusions) often generate as much anxiety as they are supposed to reduce. Thus it seems profitable to seek additional sources of anxiety reduction to understand the tenacity of delusional thinking. The current model amounts to an information acquisition and processing interpretation of paranoid behaviour. The open-style male is distinguished by his broad external scanning for evaluative cues and his selective attention to unfavourable evaluative meanings ; both attributes influence the manner in which information is acquired from the environment. Furthermore, open-style adaptation involves 5
SCP I
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A. B. HEILBRUN, JR.
a distinctive pattern of information processing - premature attribution of meaning, limited consideration of alternative meanings, and denial and projection of meaning. In keeping with an information model, our hypothesis for delusion formation also holds that the delusion is reinforced by its anxiety-reducing properties but stipulates an additional source of anxiety. The person has overloaded his capacity to process information and the delusion reinstitutes and maintains order in thinking in place of anxiety-arousing disorganization. This delusion-formation hypothesis is similar to an earlier proposal by Cameron (I~sI), who distinguished two stages of delusion formation. The hypervigilant stage leads the individual to’ view nearly all information as related to certain dominant hypotheses. The second stage is one in which the individual disregards information which is not congruent with his delusional system and by doing so avoids information overload. The present delusion-formation proposal can be recognized as a way of understanding the shift from the first to the second stage. It can be noted that several other clinical investigators have emphasized the importance of problems in information processing, especially with schizophrenics. Venables (1964)has described ‘input dysfunction’ as a part of the pathological process. He proposes that chronic and process patients experience hyperarousal and thus restrict attention to external stimulation. Acute and reactive patients, in contrast, are characterized by hypoarousal associated with a deficit in selective and inhibitory functions. Flooding of the information-processing system with exteroceptive information results. A clinical investigation of acute schizophrenics by McGhie & Chapman (1961) led them to hypothesize a breakdown in the selectiveinhibitory function of attention which floods consciousness with an undifferentiated mass of incoming information. Silverman (1964)pointed to the broad scanning of exteroceptive stimulation characteristic of paranoid schizophrenics. T h e present investigation sought to test one aspect of the delusion-formation postulate outlined above. If the postulation were correct, it should be possible to demonstrate that the proper ordering of disorganized symbolic cues is uniquely reinforcing to late-adolescent males who have adopted an open style of adaptation to aversive maternal control. METHOD Subjects
Seventy-five white male undergraduates at Emory University participated in this experiment during the autumn and winter quarters, 1972-73. They were obtained as volunteers from the subject pool maintained by the entry psychology courses. The mean age of the subjects was I 8.5 years. Emory undergraduates are predominantly from middle-class social backgrounds. Measures of maternal experience Maternal child-rearing control. Perceived maternal child-rearing behaviours were measured by means of the subject’s ratings on two questionnaires. The maternal form of the Parent Attitude Research Instrument (Schaefer & Bell, 1958) was administered to the subject with instructions to complete it as his mother would. A major factor-analytic cluster of 16 ‘authoritarian-control’scales among the 23 total scales has been identified by Schaefer & Bell (1955) and Zuckerman et al. (1958). Each scale comprised five items, each item offering
A Developmental Model of Paranoia
67 disagree ’
response options ranging from ‘strongly agree ’ (score = 4) down to ‘ strongly (score = I). The cumulative score over these 16 scales defined attributed maternal control. Maternal child-rearing nurturance. The Parent-Child Interaction Rating Scales (Heilbrun, I 964) were used to measure perceived maternal nurturance. This questionnaire includes eight related modes of parental nurturance with ratings obtained on five-point, descriptively anchored scales. Cumulative scores defined perceived maternal nurturance. Both the Parent Attitude Research Instrument and the Parent-Child Interaction Rating Scales, employed as measures of perceived child-rearing experience, have proven their heuristic valug in over 40 published investigations (reviewed in Heilbrun, 1973 a).
Thought disorganization analogue T h e symbolic disorganization-ordering-reinforcement sequence was simulated by first presenting the subject with a series of evaluative adjectives with the letters scrambled SO as to form an anagrams task. A pilot study using a mixed sample of 20 male and female Emory students was used to calibrate the difficulty of the task by varying the time allotted for solution of the 33 anagrams from 10 to 20 min. T h e zo-min. period resulted in an average of 13.9 correct solutions and was adopted as the level of task difficulty for the main experiment. T h e second task required of all subjects was a word-recognition procedure within which 66 behavioural adjectives were individually presented, slightly out of focus, for IOO msec. each by means of a Kodak Carousel slide projector. These 66 words were originally chosen from the Adjective Check List (Gough & Heilbrun, 1965) and included zz judged to reflect favourably upon the person, zz to reflect unfavourably and zz of neutral evaluative connotation. Half of these adjectives ( I I favourable-neutral-unfavourable triads) were used for the anagrams task. The subject was instructed to identify as many of the briefly exposed words as possible and was given four practice words prior to beginning.
Procedure Questionnaire administration. Questionnaires were administered in small groups, each subject being recalled individually for the laboratory session within a few weeks. T h e same female experimenter conducted both sessions. Stroop-tape procedure. The subject was presented the Stroop-tape task when he returned for the individual session, the basis for inferring open or closed styles of adaption to aversive maternal control. This involved the administration of the Stroop Colour-Naming Task (Stroop, 1935) in which the subject is required to name the colour in which each of 144 nominal colour words is printed. T h e words are never printed in the colour which they name (c.g. the word ‘blue’ may be printed in green ink). This procedure was devised to be susceptible to response interference, since it requires a reversal of the habituated reading response. After a baseline of performance had been established for the subject, a second form of the Stroop was administered. This time the subject had to perform while listening through earphones to a tape-recorded mother-son interaction. The taped dialogue was recorded by professional actors from a prepared script and represents a hostile and controlling tirade directed by a mother towards her son (Olsen, 1965). The ability of the subject to ignore the task-irrelevant aversive-maternal-control cues, after being instructed to do so, is given by his error score on Stroop no. z relative to his baseline score on Stroop no. I . Relatively disrupted performance on Stroop no. 2, indicating an inability to fend off the task-irrelevant cues, represents the operational definition of the vigilant open-adaptive style (for the maternal high control-low nurturance male) or the disrupted control group (for males having other than a high control-low nurturance maternal experience). Relatively nondisrupted Stroop no. z performance, indicating an ability to ignore the task-irrelevant maternal cues, defines the defended closed adaptive style or its non-disrupted control group, again depending upon the presence or absence of the aversive-maternal-control experience. The Stroop-tape procedure and the child-rearing questionnaires have been used as a standardized battery since 1968, thereby generating almost identically defined groups in each investigation. Accordingly, the results from all adaptive-style studies are directly comparable. 5-2
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A. B. HEILBRUN, JR.
Reinforcement value of reducing thought confusion. T h e analogue condition for testing the reinforcement value of alleviating confused or disorganized thinking involved two phases. First, the subject (after completing the Stroop-tape procedure) was told that we had taken several of the most frequently used words from a poll of mothers in which they had been asked to describe their college-age sons. This bogus information, intended to induce an evaluative set in the subject, has been used in several previous adaptive-style studies with apparent success. The subject was further informed that the evaluative words would be presented to him in a jumbled form and that he should order as many of these maternal evaluative terms in proper form as he could in the time allowed. Following the zo-min. anagrams task, the subject was told that he now would be shown the longer list of frequently used evaluative terms obtained from the pool of mothers. This time, however, the words were to be only briefly exposed on the screen, and it was to be his job to identify as many of these adjectives as possible. I t was explained that the words on the anagrams task would be among those shown. Four practice words were provided to familiarize the subject with the procedure, and these were followed by 66 test words. Completion of the tachistoscopic task marked the end of the experiment.
RESULTS
Definitions of the experimental groups Mean scores taken from Emory norms for males were used as cutting scores to define high perceived control (Parent Attitude Research Instrument control score > 192) and low perceived nurturance (Parent-Child Interaction Rating Scales score < 33). Sixteen males were defined as high control-low nurturance, whereas the remaining 59 males (high control-high nurturance, low control-high nurturance, low control-low nurturance) were combined into a general reference group to serve as controls for child-rearing experience." Assignment to open-style or closed-style groups for the high control-low nurturance subjects or to disrupted or non-disrupted control groups for the general reference group subjects was based upon a median split of the Stroop no. I minus Stroop no. 2 difference score for all 75 subjects in the study. Failure to improve on Stroop no. 2 defined disruption ( n = 37), whereas improvement on Stroop no. 2 despite the distracting cues defined non-disruption ( n = 38). Definition and analysis of reinforcement score The definition of a reinforcement score in this investigation is based upon the following two assumptions: (I) the greater the reinforcement value of organizing a previously disorganized evaluative stimulus, the greater the learning of that organized stimulus; (2) the more highly learned the stimulus, the more readily recognized it should be when subsequently presented in ambiguous form. Both assumptions appear to be readily defensible. Each subject was assigned two scores reflecting his accuracy of perception. One represented the percentage of solved anagrams which had been correctly identified in the tachistoscopic procedure, and the second represented the percentage of words
* Analysis of variance indicated that these three child-rearing groups, separated by disruption level, did not differ from one another on the major dependent variable in this expcriment.
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Table I . Reinforcement value of reduction in evaluative cue disorganizationfor lateadolescent males varying in maternal child-rearing experience and adaptive style Maternal child-rearing experience L-
7-
High control-Low nurturance
7
General reference group
Disrupted (Open style of adaptation) (n = 7)
Non-disrupted (Closed style of adaptation) (n = 9)
Score*
Mean
S.D.
Mean
S.D.
Mean
S.D.
Mean
s.~.
Anagrams Reinforcemcnt
13'14 39'19
6.54
10'22
3'09
13'07
18-20
18.40
6.05 7'72
IZ.45 22'45
13.33
14-64
16.61
Disrupted controls (n = 30)
Non-disrupted controls (n = 29)
5'01
* Anagrams score = number correctly solved. Reinforcement score = percentage correctly solved word anagrams subsequently detected minus percentage unfamiliar words subsequently detected. to which the subject had not been previously exposed in this experiment which were subsequently identified correctly when briefly presented. The latter set of words included the anagrams not correctly solved plus the 33 words not included in the anagrams task. The reinforcement score was derived by subtracting the latter percentage from the former, thereby imposing an intra-individual control for perceptual acuity. Derived in this way, a high plus score means that the person was far more able to recognize ambiguously presented evaluative words which he had previously unscrambled than a person with a low plus or a minus score, independent of his general perceptual acuity. Table I includes data relevant to the reinforcement scores for the experimental groups. Preliminary consideration of the numbers of anagrams correctly solved (row I, Table I), using a two-factor factorial analysis of variance for unequal cell frequencies (Winer, 1962), indicated no significant effect of child rearing (F = 1.24; d.f. = I , 7 1 ; P > o - ~ o )disruption , level (F < I'OO), nor any interaction effect (F < 1-00>. Accordingly, all four child-rearing x disruption level groups started from the same numerical base of correctly solved anagrams in determining the reinforcement score. Statistical evaluation of reinforcement score means by the same type of factorial analysis of variance as used with the anagrams score revealed a significant main effect of child-rearing (F = 4-32; d.f. = I , 71; P < 0.05) and of disruption level (F = 6.64; d.f. = I , 71; P < 0.025). Of greater importance, however, was the finding of a significant interaction effect (F = 13.72; d.f. = I , 71; P < 0.001) requiring inspection of the critical simple effects. The reinforcement score for the open-style males (39.19) was significantly greater than that found for either the closed-style group (16.61) or the disrupted control group (18.40); F values were 20.62 (P < 0.001for I, 71 d.f.) and 16.73 (P < 0.001for I , 71 d.f.), respectively. Thus, the predicted greater reinforcement value of removing cue disorganization for open-style males was strongly supported.
70
A. B. H E I L B R U N J R,.
Control comparison of the closed-style group (16.61)with its non-disrupted control (22.45) proved non-significant (F = 1.28; d.f. = I, 71; P > 0.20) as did the comparison of the two control groups with each other (F < 1.00).
DISCUSSION
Since the postulate under investigation in this experiment is a complex one, it is important to consider what has been tested (and supported) by the present results and what has not. The postulate states that disorganization in thinking occurs when extensive, biased and erroneous intake of information, especially of an evaluative nature, overextends the processing capacities of the open-style adapter. Such disorganization is aversive, and he reduces his distress by organizing the store of information by means of simplifying schemas encompassed within a delusional system. Finally, the delusion remains fixed because of its anxiety-avoidance properties. T h e evidence in support of the open-style male’s extensive scanning of information, his biased perception of information, and the susceptibility to erroneous interpretation of ambiguous information has been cited earlier in this paper. Similarly, his limited effectiveness in dealing with alternative meanings and his more fixed ideation in the face of contradictory evidence have been documented. T h e present evidence points toward the greater reinforcement value inherent in reducing disorganization in evaluative cues for the open-style adapter. This finding is important to the information-processing model of paranoid development, since it offers a necessary precondition to subsequent investigation of further model assumptions. Yet to be tested are the contention that the delusion serves a cognitive organizing function from which it derives its reinforcement and that the source of reinforcement which follows cognitive organization of information is the reduction of anxiety generated by disorganized thought. The model for paranoid development presented in this paper is not proposed as a singular explanation of how paranoid conditions may arise. The question of the importance of this social-learning explanation relative to other proposals remains to be answered. In fact, we would speculate that the present model would have greater applicability to the paranoid conditions associated with reactive schizophrenia than those associated with process schizophrenia. This conclusion derives from the closer parallels between reactive schizophrenic behaviour and those postulated by the model. It may be recalled, too, that Venables (1964) considered reactive schizophrenics to be susceptible to flooding of the information-processing system. We might look for the formation of delusions in process schizophrenics to be more related to the absence of informational input from the external environment. REFERENCES ALEXANDER, F. & FLAGC,G. W. (1965). The psychosomatic approach. In B. B. Wolman (ed.), Handbook of Clinical Psychology. New York : McGraw-Hill. CAMERON, N . (1951). Perceptual organization and behaviour pathology. In R. R. Blake & G. V. Ramsey (eds.), Perception: an Approach to Personality. New York: Ronald Press.
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CAMERON, N. (1963). Personality Development and Psychopathology: a Dynamic Approach. Boston: Houghton Mifflin. J. C. (1972). Abnormal Psychology and Modern Life. Glenview, 111.: Scott, COLEMAN, Foresman. FREUD, S. (1912).Psychoanalytic notcs on an autobiographical account of a case of paranoia. Standard Edition, vol. 12. London: Hogarth Press, 1958. Gowcir, H. G. & HEILBRUN, A. B. (1965).Manualfor the Adjective Check List and the Need Scalesfor the ACL. Palo Alto, Calif. : Consulting Psychologists Press. HEILBRUN, A. B. (1964).Parent model attributes, nurturant reinforcement and consistency of behaviour in adolescents. Child Dev. 35, 151-167. HEILBRUN, A. B. (1970). Perceived maternal child-rearing expcrience and the effects of vicarious and direct reinforcement on malcs. Child Dev. 41,253-262. HEILBRIJN, A. B. (1971).Style of adaptation to pcrccived aversive maternal stimulation and sclective attention to evaluative cues. J. abnorni. SOC. Psychol. 77, 340-344. HEILBRUN, A. B. ( 1 9 7 2 ~ )Distinctiveness . of maternal control: a further link in a theory of schizophrenic development. J. nerw. ment. Dis. 154,49-60. HEILBRUN, A. B. (19726). Style of adaptation to perceived aversive maternal control and internal scanning behaviour. J. consult. clin. Psychol. 39, 15-21. HEILBRUN, A. B. ( 1 9 7 2 ~ )Tolerance . for ambiguity in late-adolescent males: implications for a developmental model of paranoid behaviour. Dew. Psychol. 7, 288-294. HEILBRUN, A. B. (1972d). Defensive projection in late adolescents: implications for a developmental model of paranoid behaviour. Child. Dev. 43,880-891. HEILBIIUN, A. B. (1973 a). Aversive Maternal Control: a Theory of Schizophrenic Development. New York: Wiley. HEILBIIUN, A. B. (1973b). Adaptation to aversive maternal control and perception of simultencously presented evaluative cues: further test of a dcvelopmental model of paranoid behaviour. J. consult. clin. Psychol. 41, 301-307. HEILBRUN, A. H., HARRELL, S. N. & GILLARD, B. J. (1967).Perceived maternal child-rearing patterns and effects of social nonreaction upon achievement motivation. Child Dev. 38, 267-281. HEILBRUN, A. B. & NORBERT, N. (1970). Maternal child-rearing experience and sclfreinforccmcnt effectiveness. Dev. Psychol. 3, 81-87. HEILBRUN, A. B. & NORBERT, N. (1972).Style of adaptation to avcrsive maternal control and paranoid behaviour. J. genet. Psychol. 120,145-153. MCGHIE,A. & CHAPMAN, J. ( 1 9 6 1 ) .Disorders of attention and perception of early schizophrenia. Br. J. med. Psychol. 34,103-1 17. OLSEN,S. P. (1965). Response intcrfercnce as a function of social evaluation and maternal child-rearing expcricnce. (Unpublished doctoral dissertation, University of Iowa.) SCHAEFER, E. S. & BELL, R. Q. (1955). Parent Attitudc Research Instrument (PARI): Normative data. (Unpublished manuscript, Library, National Institutes of Hcalth, Bcthcsda, Maryland.) SCHAEFER, E. S. & BELL,R. Q. (1958).Devclopment of a Parent Attitude Research Instrumcnt. Child Dev. 29, 339-361. SILVERMAN, J. (1964).Scanning-control mechanism and ' cognitive filtering' in paranoid and non-paranoid schizophrenia. J. consult. Psychol. 28, 385-393. STROOP, J. R. (1935). Studies of interference in serial verbal reactions. J. exp. Psychol. 18, 643-672. VENAHLES, P. H.(1964). Input dysfunction in schizophrenia. In B. A. Maher (ed.), Progress in Experimental Personality Research. New York : Academic Press. WHITE,R. W . & WATT,N. F. (1973). T h e Abnormal Personality. New York: Ronald Press. WINER,B. J. (1962). Statistical Principles in Experimental Design. New York: McGraw-Hill. ZUCKERMAN, M., RIBBACK, B., MONASHKIN, I. & NORTON,J. A. (1958). Normative data and factor analysis on the Parent Attitude Research Instrument. J. consult. Psychol. 22, 165-171.
Manuscript received 20 September 1973
