Bchav. Rcs. Pr Therapy. 1971, Vol. 9, pp. 329 tu 336. Pergamon Press. Printed in England

THE USE OF OPERANT CONDITLONING TO REINSTATE SPEECH IN MUTE SCHIZOPHRENICS*t

ROGEE~ BAKER

Department of Psychiatry, University of Leeds. England

(Received 11 December 1970)

Summary-Eighteen schizophrenic patients who had been mute from 3 to 37 years were selected by means of a speech test. Nine of these were positively reinforced for speaking and nine were reinforced for staying silent. After 2.5 sessions the speech-reinforced group had improved significantly more than the silence- reinforced group.

TCrERE have been several studies aimed at reinstatin g the speech of mute schizophrenic patients, and a variety of different techniques have been used to do this. They include the

tfse of “shaping” with positive reinforcement (Isaacs ef al., 1960>, the use of imitation with positive reinforcement (Sherman, 1963; Wilson and Walters, 1966; Kassorla, 1968), the use of empathy and establishing contact {Knight, 1946), and the use of unconscious symbolism (Sechehaye, 195 1). In all cases speech was successfuIly reinstated or improved. However, as was argued in a previous paper (Baker, 1970), none of these studies, except that of Kassorla, clearly show the reinstatement of speech to be attributable to the particular technique used. The Kassorla study is a singie case study, and the results cannot be reliably generalized to other patients.

The aims of the present study were: (I) To apply operant conditioning techniques for a predetermined number of sessions, to reinstate speech in mute schizophrenics. (2) To test whether positive reinforcement is the critical factor in this reinstatement, taking into consideration that the extra attention and stimulation a neglected patient receives as a research subject, may cause an improvement.

This paper involves a report of two experiments. As the second experiment was designed as a replication of the first, the two have been compounded and will be discussed as one. Any differences in procedure which occured between the two experiments will be specified.

Pafients The selection criteria were muteness, a diagnosis of chronic schizophrenia, interest in

one or more of the available reinforcers, and some degree of co-operation (e.g. that the patient did not walk out of the experimental room).

* I would especially like to thank Professor MAX H.WKTON, Dr. ARD~E LUBIN and iMr. RALPH MCGUIRE for their help with virtually every aspect of the study.

t Based on part of a thesis to be submitted to the University of Leeds in fulfillment of the requirements for the Ph.D. degree, and supported by grants from the Porton Trust and the Mental Health Research Fund of Britain.

329

330 ROGER RAKER

Mzlteness. The nurses were asked to select totally mute patients. Case notes were consulted and a history of total mutism ~vas necessary for inclusion in the study. Periodic mutism and deaf mutism were excluded. Throughout the early pre-treatment sessions. a patient was excluded if he spoke anything more than the occasional word. The diagnosis of chronic schizophrenia was the most recently recordeddianosis in thecase notes. Patients were excluded if they were schizophrenic plus some other diagnosis, for instance congenital mental deficiency.

In the first experiment ten patients were selected, these representing the entire population of mute schizophrenics at Stanley Royd Hospital, Wnkefield, within the bounds of the criteria above. In the second esperiment eight patients were selected from various other hospitals in Yorkshire, and moved to Stanley Royd Hospital. Of the total patients selected, four were female, and fourteen male, their ages ranged from 27 to 69 years (mean j3), and their length of time in hospital ranged from 16 to 42 years (mean 29). Their histories of mutism ranged from 3 to 37 years (mean 22). If a patient was on drugs before the experiment began, these were maintained, but, if not, none were introduced during the experiment.

Apparntrrs

All measures of speech involved asking questions and scoring each reply as follows: 0 for no reply, 1 for a grunt, 2 for an inappropriate or imperfect reply, 3 for a perfect reply and 4 for a perfect reply plus some extra speech.

A standard questionnaire (referred to as the conversation test) acted as the main pre and post measure of speech. It comprised 60 items, ranging from Yes/No to open-ended questions. Inter-rater correlations on pre and post measurement in Experiment 2 were both r=0.99. To measure speech durin, 0 treatment, alternate sessions were scored in three

time-sampled phases (l-3, 15-18, 30-33 min). The nurses kept a record of the patient’s reply to the question “How are you feeling

today?” asked twice a day for a week. (In the second experiment the question “Are you

happy ?” was added.) In the first experiment this acted only as a pre and post measure of speech, but in the second it was continued during treatment.

Pretreatment procedwe

The first meeting with a patient was a short selection interview, followed a week later by a “rapport session”. This was held to determine what constituted reinforcement for each patient, to exclude non-mute and non-cooperative patients and to establish “rapport”. (Gelder, 1965, has sho\vn the importance of the preliminary interchange on subsequent conditioning.)

The “conlersation test” was then given at approximately weekly intervals to establish a baseline for verbal behaviour. It was given twice in Experiment 1 and six times in Experiment 2. Questions were read at the rate of one every S-l 5 set, with as much expression as possible. No reinforcement was given. To establish a pre-treatment baseline for speech on the ward, the nurses kept a record of the patient’s replies for one week in Experiment 1, and four weeks in Experiment 2, without reinforcement.

Patients were paired on their last pre-treatment conversation test score and duration of muteness, and one member of each pair was randomly assigned to an experimental group, the other to a control group.

Treatment procedure Each patient individually received 25 treatment sessions. Experimental patients were

positively reinforced for verbally respondin g to questions, but not for staying silent, and

THE USE OF OPER.ZST COSDLTIONING TO REWSTATE SPEECH IS AMUTE SCHIZOPHRESICS 33 1

control patients were positively reinforced for staying silent to questions, but not for verbally responding. Reinforcement consisted of chocolate, sweets, fruit drinks, milk, cigarettes, or looking at a page of a colourful magazine, paired with social approval. For each patient the type of approval that occasioned the most positive facial expression (e.g. smiling, eye- contact) was used, so there was some variation between different patients. It generally consisted ofphrases such as“that’s lovely speaking” or “well done”, smiles, nods of approval and sometimes hand-shaking or hand-holding. Social approval was paired with material reinforcement so that if it was not already a reinforcer it mightacquiresecondaryreinforcing properties during the course of the experiment. initially reinforcement was continuous, but if conditioning was successful, ratio schedules were introduced.

Within this general framework, the following supplementary procedures were ex- perimented with, and if successful, continued. To initially reinstate speech the method of shaping, as used by Isaacs (1960), or the method of imitation, as used by Sherman (1963), were tried. Stimulus fading was also used, especially in conjuction with imitativeprocedures, where fading of an imitative prompt might be employed to enable a patient to produce

words of his own (Sherman, 1963). Sessions were held in a set side room of the patient’s ward and lasted approximately

45 min. For each patient there were two sessions a week. For each pair, the session for the control patient followed that of his experimental counterpart and was of a similar form, except for the reinforcement contingency.

In Experiment 2 the nurses likewise reinforced experimental patients for speech, and controls for silence during the treatment period.

Post-treatment procedure After each patient had received 2.5 treatment sessions he was given the conversation

test three times without reinforcement. Nurse’s post-treatment measures were also taken without reinforcement. A “crossover” period now ensued for the control patients. This

consisted of 25 sessions where reinforcement was contingent upon speech and no longer upon silence. After the crossover, post-treatment measures were taken for all patients.

For patients in Experiment 1 the conversation test was given after a year of no- treatment, as a follow-up measure.

Mnin experiment RESULTS

(I) The conversation test. Each experimental patient was matched on his pre-treatment score with a control patient. After 25 treatmentsessions the change score for eachpatient was calculated as the first post-treatment score minus the last pre-treatment score. The difference between the change scores of each pair (E-C) was taken as a measure of the reinforcement effect. The data presented in Table 1 reveals that experimental patients improved more than their control counterparts, and the difference was significantly greater than zero (t=2.8, s.d.=27.9, d.f.=8, ~~0.05).

(2) Session scores. Speech was measured during sessions in three time-sampled phases. This method of scoring enabled a measure of progress to be obtained both within sessions, and from session to session.

(a) Changes from session to session, For each patient the correlation between session number and his mean score for the three phases of that session was used to represent his overall session to session trend. The difference between the r-transformed coefficients

332 ROGER BAKER

T-\BLE 1. hE, POST AND CHASGE SCORES OS iiTHE CONVERS.ITIOV TEST” FOR EACH PATIEXT, AND

THE DIFFEREXCE IN CHASGE SCORES k0R EACH P.UR (IS :;)

Pair

Experimental patients

Pre Post Change

Differences Cdntrol pati+Zntj in change

(exp-control) Pre Post Changs

! 1 47.1 53.9 6.8

2 14.2 35.4 21.7

Experiment 1 3 3.3 19.6 16.3

14 O 2.1 2.1

15 0 59.6 59.6

6 33.3 61.3 2s.o

7 3.8 25.4 21.6 Experiment 2

8 0 4.6 4.6

9 0 62.1 67.1

x 11.3 36.0 24.7

s 17.3 24.3 22.2

49.2 63.3 14.1 -7.3

20,s 16.3 -4.5 35.7

S.0 0.S -7.2 23.5

0.4 3,s 3.4 1.3

0 0 0 59.6

46.2 12.5 -33.4 61.4

4.6 9.6 5.0 16.6

0 6.2 5.2 -1.6

0 2. I ‘.I 60.0

14.4 12.8 -1.6 26.3

20. I 19.8 13.4 ‘7.9

of experimental and control palients of each pair was taken as a measure of the reinforce- ment effect. The mean difference was O.S3, which was significantly greater than zero (t=2.5, s.d.=0.99, d.f.=& p<O.O5).

(b) Changes within sessions. The mean score over all recorded sessions for each of the first, second and third time-sampled phases was shown by analysis of variance to rise significantly for experimental patients (~~0.05) and to fall, though not significantly, for control patients. The difference between experimental and control patients was significant (p<O.O5).

(3) A ~nec~~re of extinction. The three post-treatment conversation testsinvolved a total of 1 SO questions without reinforcement, thus constituting an extinction period. Experimental patients showed a fall in speech score over the three tests and controls showed the expected rise in speech, although these trends were not sigtiticant. Analysis of variance revealed the difference between experimental and control patients to be significant (F=5.64, d.f. 2116, pcO.05).

(4) Speech scores kept by the nurses. Experimental patients improved by a mean of

23.1 per cent, and controls by 4.3 per cent, but the difference in improvement was not significant (t = 1.6, s = 35.0, d.f. = 8). The difference in improvement for Experiment 1 alone (in which the nurses did not participate) was 4.3 per cent, and in Experiment 2 (where the nurses did participate) it was 37.1 per cent. There was no significant difference between these scores (t= 1.5, d.f. =7). One of the most interesting ward records of the speech of a control/experimental pair of patients is presented in Fig. 1. It is apparent in the scores of

the control patient that the symptom of mutism can be created in a non-mute patient by the nursing procedure. For the experimental patient, there was not the decline in speech during

THE USE OF OPERANT COEDITIONISG TO REINSTATE SPEECH IN 1ttiTE SCHIZOPHRESICS 333

FIG. 1. Ward speech scores for the experimental and control patients of pair 6. For the purposes of illustration the original weekly scores are here averaged into fortnightly scores. This gives the appearance of a rising baseline. In fact, for both patients the scores of week 4

sharply declined from the scores of week 3.

the post-treatment non-reinforcement period that might be expected. AIthough reinforce- ment was continuous on the ward, variable ratio schedules had been used during sessions and a generalisation of their effect might explain the resistance to extinction on the ward.

The crossover During the crossover the conversation test scores of control patients showed a mean

change of IS.9 per cent. The difference between this and the change during the main experiment (- 1.6 per cent), was not significantly greater than zero (t= 1.9, s==32.4,

d.f. = 8).

Follouwp The conversation test given a year after treatment to all patients showed a mean decline

in speech of 4.7 per cent from the last post-treatment test score. This decline did not differ sjgnj~cant~y from zero (t= 1.5, s=9.5, d.f.=9).

Qimlitntive rmilts The following were observations concerning the quality of speech produced by operant

conditioning methods. Firstly, for most patients speech was only in reply to questions and not spontaneous. Secondly, for some patients speech was automaton-like: it was spoken quickly and mechanically and the content and form were predictable. Often nothing involving thought could be conditioned. For instance a patient might repeat words but could not be conditioned to name objects. Automaton-I&e speech was the casewith the experimental patients of pairs 2, 5 and 9, and the control patients of pairs 3 and 4 in the crossover. They tended to be “textbook” cases of conditioning, but as imitative procedures were the most successful in initially reinstating speech a “textbook” case had necessarily undergone imitative training. There was one patient whose replies were animated and clearly not automatic, and it may be pertinent to note that his speech wasreinstatedin one trial, as opposed to the numerous trials experienced by other patients.

An earlier progress report (Baker, 1970) gave more details of a qualitative nature, but briefly it was reported that during sessions, certain conditions lead to a return to mutism, or in a few cases response stereotypy (repeating the same word to all questions). Some of

:34 ROGER BAKER

these conditions were: short intervals between questions (under ten seconds), repeated asking of the same question or type of question (e.g. colour naming). or if too much reinforcement was withheld (for instance for inappropriate behaviour). Generally, as a prerequisite for sucessful conditionin g, it was important to be extremely warm to patients.

DISCUSSlOb

Mute schizophrenic patients who were reinforced for speaking improved more than those reinforced for muteness on all measures of speech, including a standard measure of enduring change (conversation test), measures of session to session trend, and at a more molecular level, measures of within session trend. There were also appropriate, but in- significant differences for speech on the ward, and significant appropriate extinction effects. During the crossover when control patients were reinforced for speech, they talked more than they had done when reinforced for silence, but this was not significant. A follow-up study administered a year after treatment revealed no significant decline in the conditioned behaviour. IJnfortunately the nature of the treatment precluded a double blind approach and therefore it could be claimed that experimenter expectancy effects influenced results (Rosenthal, 1966).

Many ideas have been put forward to explain causes for mutism (Bleuler, 1950; Ferster, 1965; Fromm-Reichmann, 1959; Sechehaye, 1956). In the present experiment the case histories revealed either a sudden onset of mutism, which often precipitated admission to hospital, or a gradual onset durin g the stay in hospital. Figure 1 illustrates that one way in Lvhich mutism of the latter kind can be formed is through inappropriate reinforcement by the nurses. This might occur in a more natural setting if a patient’s only speech is incoherent or delusional and the staff, considering it to be nonsense, ignore it. However, inappropriate reinforcement should not be generalised to explain all cases of institutionalised mutism as is evident in the improvement of speech of the control patient of pair I when he was reinforced for silence.

One finding of relevance to future therapeutic endeavours which use operant conditioning techniques was the mechanical quality of speech produced in several patients. The three attributes which gave speech its mechanical appearance were its total bond to the SD (question), the predictability of form and content of the reply, and the inability for verbal behaviour which reflected thinking to be conditioned, (although this was consistently attempted for many sessions). The first, a problem of too much stimulus control, might be remedied by the use of free-operant procedures, so that the patientresponds in hisown time and at his own initiative, as often occurs in token economy programs. The other attributes might have been a function of one or more of the following:

(1) If speech reinstatement is viewed as a shaping process, behaviour that is initially reinforced must eventually be extinguished as the desired end result moves nearer (Sidman, 1962). Too much reinforcement for any one approximation might conceivably cause the organism to get “stuck” at that level, and parrot-like speech can be seen as such.

(2) The use of imitative procedures might explain mechanical speech. (3) The phenomenon might be explained as a function of the schizophrenic illness

and/or (4) Operant conditioning with these patients modifies overt behaviour only, leaving the

mental state unchanged. Other findings concerned certain conditions which for some patients engendered a

temporary return to mutism and for others the production of a stereotyped word. These

THE USE OF OPERAST CONDITIOSING TO REINSTATE SPEECH IS 51 LTE SCHIZOPI:RESlCS 335

conditions(e.g. short inter\ als between questions) involved some sort ofpressure on the patient and might constitute aversive stimuli. An impairment in the performance of schizophrenic patients in many spheres haselsewhere been found to occur in socially aversive conditions (Rodnick and Garmezy, 1957). A further finding was that a continuously present emotional warmth from the therapist appeared to be an important prerequisite for successful con- ditioning. Although the essential parameters of “warmth” in this experiment cannot be fully specified, it resembles findings by others in this field. For instance Ullmann and Krasner (1969) refer to “human kindness tact, sensitivity and a genuine respect for the person as an individual” and Meichenbaum (1969) to” psychological contact” as essential conditions without which operant conditioning might not be successful. Reece and Whitman (1962) operationally defined “warmth” as leaning toward the patient, looking directly at him, smiling and keeping the hands still, and showed it to be an important variable in faciliating verbal conditioning. In view of the finding that the presence of the therapist may be aversive for schizophrenics (Gelburd and Anker, 1970) the establish- ment of a warm relationship might function to counteract this social aversiveness, to maximise the positive reinforcing properties of the therapist’s social approval (Truax. 1966) and to sustain the patient’s attention to the task in hand (Meichenbaum, 1969).

In summary, this study showed that operant conditioning techniques did cause a significant and lasting improvement in the speech of chronic mute schizophrenic patients, and that this improvement was a function of the reinforcement contingency. However, in view of the unnatural quality of the conditioned speech of several patients, the meaning- fulness of the improvement needs some consideration.

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