CHAPTER l[ HISTORICAL RESUME

In chapter I noise was defined and it was high lighted

that there are marked individual differe'-'ces in the way people

react to it,, This chapter presents an chronological review of

research regarding the effects of noise on human performance

and its psychological and physiological reactions.

Survey of related literature means to locatb, to read

and to evaluate the past as well as current literature of

research concerned with the problem in h(Hnd for investigation.

By surveying the related literature the risk of duplication is

avoided,, The surveys provides ex prei.men ta 1 results, ideas and

explanations, which are helpful and valuable in the research.

The main purpose of historical resume is not just compilation but it is an analytial review of the various resources. The

1 sti.id.ies done in tli.i.s area infact have suggested riew i.deas arid

acquaiii tance to tlie current field or area. The survey has

enabled the investigator to avoid useless and unfruitful

problems. There is infact lot of controversy with regard to

the effects of noise on performance.

24

One of the earliest studies on noise was done by

l<: o r n fi u B e r (1,927). He conducted an investigation on f o u r

typists and found no significant difference in quiet and noisy

conditions when errors, the amount,of material typed and

number of discarded letters were considered.

Ford (Jl,929) repjorted that not only noise but. quietne»ss

can also act as a distractor. The quietness like noise can

also act as a distractor to some^ individuals,

Clupin and ESmiths (1930) throws light on the type of

people particularly suscesptible to noise. The fallowing groups

worked in a noisy environment and each person^ was |.nterviewed

later on,,

a) A group of thirty girls working at or near a very

noisy process called stamping and a group of nineteen

typists vMorking on ordinary machines in one room.

b) A group of nineteen male students who worked under

fairly quiet conditions, disturbed at intervals by

t r a f f i c n o i s e .

<•••) A grouip of one hundred and fifty-si;-! males whose work

was sometimes done to the accompaniment of much noise.

E:a.c.h person was asked how he or she felt. ,when they

^̂ lorkecJ under noise,, The responses could be classified roughly

i n t o 3 C a t e g o r i e s s ••-

(i) those indicating indifference to unavoidable noise,

(ii) those indicating slight dislike.

(iii) those indicating serious susceptibility to noise

SQ that physical symptoms or mental distress was set up„

In the first group of forty nine girls, 17 were graded

as well balanced emotionally; out of them 71K were not

affected by noise while 1B7. were seriously affected. Thirty

two had nervous symptoms to some degree and of these only 167.

were unaffected while 637. w.^re seriously affected. The group

of male students contained an unusually high proportion of

nervous subjects^, of the sixteen nervc>us 63"/. were affected

while 37.57. were not affected. The group of one hundred and

fifty-si;-; men yielded almost similar results of the 517, who !

were free from Symptoms., 42 were unaffeected by noise; of 79

with stjvere nervous Symptoms only 427. were unaffected.

26

F'ollock and Barlett (1932) asked undergraduates to

perform certain tests ranging from tests of manual performance

to tests de?manding partly motor and mental activity and to

tests almost entire?ly of a me?ntal type. The conditions under

V'.ihich they were applied differed from varying degrees of noisy

surrounding to almost complete quie?tness. The results showed

that noise did produce slight reduction in efficiency at the

beginning of the tests but this initial effect soon wore off

and adaption to noise took place. Discontinuous low mechanical ) I

noise was more disturbing than continuous low mechanical

noise. More loudness was not important, for soft gramophone

noises proved almost as di'"tracting. They reported that the

E'ffect of noise depends on its kind and the? type of work „

Mental work is affected more than manual work.

Finkle and Poppen (1948) did experiment in which

Volunteer Ss were exposed to turbojet engine noise of a

maximum overall sound pressure level of 120 db for a total

time of 20 hours over a 6 week period. They revealed that

apart from other effects the personal characteristic of the

.1.i'icl J. vJ,dua 1 HiubJ ec: t and his degree of susceptibility to noise

effects play an important role in the performance.

27

Bangui i and Rao (1954) carried out. an investigation in

a Calcutta jute textile factory. The Ss were eight weavejsr in a

.jute mill with normal auditory acuity and having an average of

10 Yrs experience? of weaving. The noise level in this part of

the factory was highest (97 db). The workers were given

Mai lock-Armstrong ear defenders. These cut down the noise

enter.i.ng the ears by about 9 db. The study continued for 28

weeks. During this period every S was using the defenders on

alternate weeks and thus each S served as his own control. The

worker's production during the quiet weeks W£.̂ s compared with

his production during noisy weeks. The results indicated that

effect of noise reduction on efficiency varied from worker to

worker. Some individuals were found to have high

Susceptibility to noise compared to others. The study also

suggested that more studies should be made to understand and,

isolate the factors responsible for high susceptibility.

Dana (1957) failed to find anv relationship between

anxiety and intelligence. At least part of the difference in

r e s u 11 s;. i s p r o b a b 1 y a 11 r i b u t a b 1 e to i n t e 1 1 e c t u a 1 a b i 1 i t y

levels of sample used, the studies reporting no relationship

i.tsually used college students. Spielberger (1958) obtained

28

empirical, evidence that negative correlatian between measures

of anxiety and intelligence were more prevalent in samples

containing a sizable proportion of subjects with low ability. i

Broadbent and Little (1960) conducted a study in a film

processing plant in England to find out the effect of noise on

work- The results showed that the rate of work did not improve

by noise reduction but the errors came down significantly. It

was also observed that in certain types of tasks- Such as

wor k in v(d 1 ved in tIte inspec ti.on of items on a con veyor be 11

which demanded high spee?d in responding to stimuli, noise had^

an adverse effect. It is widely assumed in industry that 90

decibels is a scientifically established 'safe' level of

noise. This is not so, as the scientists, who set the standard

have had a second thought over it. i

Canter and Stringer (1975) reported that wide

differences in response to noise have appeared in many

settings, and are apparently independent of age, gender and

educat ion ,.

Weinsteiri (;1.97£)) investigatec;l dif ferences among

individuals in their initial reactions to noise. College

freshmen .(N 155)) completed a self-report measure of noise

29

senBitivity before they came to dormitory. Two sub groups were?

constructed from students whose noise sensitivity scores fell

within either the top or bottom 30"/, of this group. Each had

nearly equal number of males and females. Self, report of

dormitory noise disturbance were obtained from the noise

sensitive group (n - 24) and noise insensitive group (n - 31).

As predicted, noise sensitive Ss were much more bothered by

dormitory noise, compared to noise insensitive students.

dtsBarben^a (1981) expressed the effGc|:s of intense,,

intermittent, axnd unpredictable, noise (80,- 100 db) on 59 Ss

(aged 18 49 yrs) performance on an arithmetic task,, Changes

in activation level we?re assessed through measurements of GSR

and heart rate;' variables such as neuroticism and introversion

extraversion were examined through Eysenck Personality

Questionnaire. The deterioration in performance of Ss judged

non-sensitive to noise was related to an increase in I activation level,, Ss sensitive to noise showed a performance

decrement due to factors such as level of neuroticism and

noise Susceptibility as well as the masking effect o'f noise

itself.

5 (J

Jonah et al (1981) reported that there are some

individuals who are intensely annoyed by noise even at very

low levels and although this proportion increases with the

level ̂.of noise, yet at the highest level of exposure a few

i. 11 d i V i d u a 1 ' s w i 1 1 r - e rri a i r'l u n p e r t u r" b e d . '

Smith (1982) has pointed out in one of their previous

studies that noise improves performance on a primary task, and

impair performance on a secondary task.. In th^ present study,

this was confirmesd in the first ex per ime?.n t ̂ with 45 adult

femalss which us6?d a modified version of Hockey and Hamiltan's

(1970) task of memory for order and location. A second

experiment with 40 Ss showed that the effect was due to noise

interacting with task priority and not with the identity of

the task performed first rather than second. A third

experiment with 17 Ss showed that priority instructions haveo I to be effective?,, for there to be an interaction between noise

and priority. It is suggested that a major effect of noise is

to bias the allocation of evffort towards the operation that

appears to best repay the investment of more effort. This may

take the form of a bias towards the high priority task, but

the effect of noise is also likely to depend upon other

factors, such as the difficulty of each part of the task and i

31

11-1 e sa lience; of tfie s t imu .1. i .

Weinstein (1982) reviewed the research on whether

people adapt easily to noise or not. He found little evidence

that any adaption occurs in Community Settings. Much of this

research., however, is open to alternative interpretations. The

present study examining reactions to traffic noise from the j I

opening of a major new highway was designed to remedy many of

the problems' with previous research. The investigation

incorporated both a repeated- measures design and an

independent groups design. In addition, a pre-opening

interview was carried out with the repeated measure panel,

There was no evidence of appreciable adaptation to

se 1 f••-reported noise effects, annoyance, or tendency to focus

attention. Instead somejSs became more pessimistic about their

ability to adapt to noise as time progressed.

Johansson (1983) studied the mental performance and

writing pressure or 66, 10~yrs old children for 2 hours, under

3 conditions, silence, continuous noise and intermittent

noise. No significant main effect of noise or interaction

between noise and personality were fdund. However, Ss with

high intelligence solved more items on a mul t,ipl ication task

in noise than in quiet condition„ The reverse was found for Ss

with low intelligence who were also more affected on the

reading task.

Iwata's (1984), did study and it was hypothesized that I Bs whose noise sensitivity level was high tend to be less

healthy than those whose level was low. 33 Ss who scored high

on author's (198.1) noise sensitivity scale and 33 who scored

low, were selected from a sample of 132 under graduates. These

two groups were compared using the Japanese version of the

Corne?:i 1 Hedical inde;; . Results supported the hypothesis. In

second study it was hypothesised that maladjusted

persona 1ities would be manifested more often,by those whose

noise sensitivity level was low. Following the same procedure

of selection in the preceding study, 35 Ss whose noise

Bensi+;?ivity was low were chosen from a.nother sample of 129

college students, using the Vastabe Guilford personality

inventory, the two groups were compared in terms of

diBtril,.u..ition of personality types. The second hypothesis was

also cc:n firmed .

Woodside and Blenesk (1984) did study and used 74

senior University students as Ss in an investigation of

consumer information processing of print advertisement ih low

noise (LN) versus high noise (HN) conditions. Low noise (LN)

conditions consisted of exposure of 5 ads within a brief time

period while-? high noise (HN) condition consisted of exposure

to 10 ads within the same period. Ss'were assigned to one of

two LM or HN conditions before participating in thought

verbalization experiment in which Ss were asked to verbalize

their perceptions after seeing the ads. Fs'esults showed, that

decli/ie in ad mentions occured for all ads between the LN and

HN conditions. The number of thoughts generated and the order

of ad. mentions varied substantially between ads. It was

suggested that the methodology used might, be useful in

1 e a r n i n g , i f 11 "i e a d . for a specific brand gains t p r o c e s s i n g

space in a consumer's mind when the consumer is exposed to

several competing ads in a brief period of time.

Jewell (1985) is of the opinion that people who are high sensitive to noise? may have receptors that are more sensXt.1Ve to noise than others.

Margarent (1985) collected data. using ^ 24 items

se)l f--report measure of disturbance due to hospital noise, from

150 male post-operative patient at a VA hospital. Results

34

B h Q w e d t h a t the m (e a b u. r e In a d a r e 1 ;i. a b 1 i t. y cd f .944 g e n s i t. .i. v i. t y

to noisE? in gene?ral was significantly prcdictive of

disturbance due to hospital noise as was an objective measure

of noise the average amount of running machinery in Ss room

each day. A hierarchical multiple regression showed

consistency with these results once variance due social

desirability was accounted for. Findings provide support for

the contention that sensitivity to noise and objective noise

are predictive of reactions to environments. ,

Darley et al (.1986) pointed out that people quickly

adapt to or stop noticing the noise that they often hear,, But

as noise ceases to be a conscious irritant or ?^ource of alarm,, 1 its effect on the autonomic nervous system may continue,,

Though, the auditory consequences of long-term exposure to

loud noise are well known., noise exposure may also be?

associated with a variety of non-auditory health effects,

ranging from cardiovascular disease to attentional deficits.

Non auditory effects are defined as "all those effects on

healtl'i and well being which are caused by exposure to noise I with the exclusion of effects on the hearing <brgan. Most

non auditory effects reflect a response to primary stimuli

through hearing organ, which stimulates the acoustic cortex

35

and Retricular Arousal. System (RAB)- The F<AS activates the

higher cerebral centers and also sends the stimuli to the

autonomous nervous system in the hypothalamus and through this <

indirectly to the adrenal medulla (enhance excretion of

cathecolamines) . lioreover., the RAS has also connections with

the hypophysis through hypothalamus;, this stimulates the

adrenal cortex to enhance excretion of Cortisol. Finally, the

RAS effects, the limbic system and consequently emotion and

mood. Noise is discussed as one possible risk factor for

essential hypertension (Andren, 19S2), Epidemiology studies

have shown that workers in noisy factor'y environiqent tend to

have higher blood pressure and a greater frequency of I hypertension than workers in relatively quiet factory

environemnt (Parvizpoor 1976; Jonsson ?< Hansson,, 1977).

F-urther Jonsson & Hansson (1977) reported that "repeated and

prolonged exposure to a stressful stimulus may be contributing

factor to the rise in blood pressure.'

(

Evy et al (198S) in his study took 93 university

students,, The subjective noise annoyance after exposure to

noise L.inder laboratory conditions were assessed. Subjective

noise sensitivity, attitude to noise, mood and personality

characteristics were evaluated using questionnaires. Results

36

indicated that annoyance after exposure to noise w'as highly

correlated with subjective reported nois;e sensitivity and with

a 11 i t u d e t o n o i s e ,,

t

Laul et al (1988) revealed the relationship between

noise sensitivity and mental decoding task „ Aftt?r

administering the Hindi adaptation of Weinstein's noise

sensitivity scale on two hundred students, a sample of one

hundred students was drawn. This study was based on multigroup

design with ten subgroups having ten subjects in each. Five of

these subgroups belonged to low, while the remaining five to

high noise sensitivity groups. The efficiency criteria

included quantitative, qualitative aspects of output, the

physiological energy expenditure inferred from increase in

oxygen consumption and subjective feelings- Results indicated

that due to adapticjn efficiency was not much affected in the

case of low noise sensitivity Ss, but adaptation was not i effective and efficiency on mental work was adversely affected'

in the case of high noise sensitivity group. 1

Petit et al (.1988) conducted an e:><periment on 13 female

adults. They were exposed in 3 sessions to regularly

alternating pink noise steps. Different techniques, were

37

pi-DpoBed to cope with individual di f ferences in cardio

vascular re^sporvses. The Ss were sensitive, ; moderately

sensitive, poorly Sensitive. Sensitive Ss always reacted

strongly towards noise, poorly sensitive always reacted

poorly. No sign of habituation of responses to noise steps was

present in any subgroup with repeated exposure.

Dormic et al (1990) did four experiments involving two

thirty eight universities students» They examined the I

relationship between extraversion and neuroticism and a series-,

of variables that are assumed to reflect gene<-al and specific

responses to noiseu Extraversion correlated negatively with

the self-reported cross-situationa1 . sensitivity^ with the

stress Arousal cl'nscklist (EiACL) j with noise—induced irrita tion

and disturbance with feelings of tension,, and general

situation annoyance (discomfort). Neuroticism correlated i positively with the SACL stress factor, noise-induced

irritation and disturfcjance task-related efforttension and

general situational annoyance; and negatively with

concentration on task. Results are discussed in context of

process mediating between the stressor' and the injdividua 1 ' s

respon'^e.

38

The precaeding review of the pertinent work in the area

of noise clone during the past many decades clearly indicates

that earlier there was a lot of disagreement pmongst the

(sarl .l.f.»r tlndingi-Broadly iipeaking on the basis of results

the studies could be classified under three categories -• those

indicating adverse effects . of noise, those revealing that

noise; enhances output and lastly claimirg that noise does not

affect work efficiency,

Batra et al (1991) conducted a study in which Hindi

adaptation of Weinstein's noise sensitivity scale was

adniinistered on 400 post-graduate students, a sample of 60 Ss

30 of high and 30 of low noise sensitivity was drawn

randomly. An atte?mpt was mad_e to investigate the effect of

en v i r oI'iinen t a ]. c oa>niun i ty noi se on a mu 11 i 1 ic a t ion tas .

Quantitative mental output and physiological energy

expenditure, inferred from the drop in skin resistance were

measured., They reported that there is a relationship between

noise, noise sensitivity levels £And mental work.

Shipra et al (1991) found on the basis of qualitative,

quantit-ative, subjective reports and physio 1 ogica 1 expenditure i

that the work efficiency of low noise sensitivity group was

not. affected by low intensity of noise though high intensity

noise disturbed them up'̂ o some eKtent. On the other hand high

noise sensitivity group was disturbed by both low as well as

high intensity of noises.

Laul et al (.1992) done the study to investigate the

effect of noise on work output and e:-;tra-auditory functions in

low and high noise sensitivity subjects. Three independent

variables noise sensitivity level (tlow and high), type of

noise - Quiet, Camp (c), Camp (i), factory (c) and factory

(i)p and nature of task (Arithmetic, Decoding^ Ergographic and

f~oot lifting tasks;.) were taken to investigate how they

influe^nced the efficiency in terms of work output and

physiological energy expenditure inferred from increase in

blood flow, blood pressure (systolic and diastolic), pulse and

respiration rates of Ss. The experimenter also wanted to

investigate any possible interactions amongst |t:he three I

independent variables., The results indicated that all the

three variables significantly affected 'the output. The

physiological parameters were significantly affected by the

noise sensitivity level and the nature of task„ Interestingly

noise only showed significant effect on pulse rate.

Significant interactions among them showed that these

4 0

variables were not only affecting the dependent variable

independently but they were also interdependent in'nature in

the sense that the effect of one independent variable on the

dependent variable was determined by the values assumed by the

other two independent variables., Noise led to lowering of work i

efficiency only in the case of high noise sensitivity Ss. It

did not adversely affect the Ioiaj noise Sensitivity S<s who

performed be^tter under the various noise conditions.

With this background, we may now pass on the next

chapter dealing with the problem and hypothesis.