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by Dr.
Lorraine E. Maxwell & Dr. Gary W. Evans of Cornell University; from
DesignShare.com
There is a considerable amount of research documenting the effects of
noise on children. The effects are largely negative. In this presentation
I will briefly describe the findings of research in this field, discuss
current research by Maxwell and Evans, and finally outline design issues
related to noise and child care centers.
Nonauditory effects of noise (see Evans & Lepore, 1993 for a more
detailed description)
Much of the research on noise and children concerns damage to the auditory
system. While the possibility of hearing damage is, and should be, of
concern to parents and educators, the nonauditory effects of noise on
children also deserves attention. The literature on the latter topic falls
into three categories; physiological effects, motivational effects, and
cognitive effects.
Physiological effects Elevated blood pressure levels in school-aged
children is associated with living or going to school near a major noise
source (e.g., airport, traffic, trains). Although the blood pressure
levels of children exposed to these major noise sources are within the
normal range, they are higher than for children not exposed to major noise
sources. These elevated blood pressure levels are of concern for two
reasons. One, the levels do not habituate with continued exposure, and
two, elevated pressure levels in children appear to continue this pattern
into adulthood thereby increasing the risk for cardiovascular disease. The
decibel levels in these studies ranged from 95 to 125 dBA peak. In each
case the noise exposure was chronic.
Motivational effects Research findings suggest that exposure to
uncontrollable noise may make children more vulnerable to learned
helplessness. Learned helplessness means that the individual learns that
the outcomes of it's behavior are independent of the actions of the
individual. Most of this research has been with school-aged children,
including kindergartners. One study found that children attending a school
near a major airport were less likely to solve a challenging puzzle and to
persist at it as well. Another study found that children exposed to noise
were more likely to abdicate their choice for a reward to their teachers.
The children decided to let the adult pick a prize for them rather than
exercise their option to do so. Teachers in noisy schools also report
greater difficulty in motivating children in their school work. Children
often had less tolerance for frustration.
Limited work has been done with younger children. One study in a
residential setting found that 12 month-old infants in noisy homes
exhibited less mastery-oriented play behavior with their toys than their
counterparts in quieter homes. The peak noise readings in the studies
described above was 95 dBA.
Cognitive effects Most of the research on the nonauditory effects of noise
on children has been on cognitive effects. The research has looked at
memory, attention/perception, and academic achievement.
The research on memory and noise for children parallels that of adults;
there appears to be little or no effects of noise on simple memory. This
holds true for both chronic and acute exposure to noise. However, if the
memory task requires special attention there does appear to be some
negative effects of noise. In other words, if the individual has to pay
particular attention because of the difficulty of the task, noise may
interfere with the memory task. Noise levels in these studies were in the
range of 22 - 78dBA.
The research on attention suggests that children exposed to chronic noise
may suffer deficits in this area. Children exposed to chronic noise seem
to develop cognitive strategies for coping with the distracting effect of
noise. Young children (5 years old) from noisy residential environments
seem to be better able to tune out distracting auditory stimuli when asked
to perform a discrimination task in a noisy environment than children from
quieter homes. Four year old children from noisy day care centers
performed better under noisy conditions than children from quiet day care
centers. These young children seem to be resistant to the distracting
effects of noise because they tune out the noise. However, additional
research suggests that as children get older (school-aged) this advantage
disappears. In these studies older children from quieter environments were
better at discrimination tasks done under noisy conditions. These children
were able to screen out the noise and concentrate on important cues.
Children from noisy environments learned to tune out auditory stimuli but
in a nondiscriminatory way and tuned out important cues.
Noise seems to interfere with children's ability to discriminate between
meaningful auditory stimuli, especially speech. Background noise, in
particular irrelevant speech, interferes with children understanding the
spoken word. This may have particular implications for children's academic
performance.
Several studies have documented a link between noise and academic
achievement, in particular reading. Acute noise appears to have little
long term effects on reading or other intellectual activities; however,
the research indicates that chronic noise has a negative effect on
children's reading skills. There is also evidence to suggest that children
from noisy homes and in noisy schools are at more of a disadvantage than
children from quieter homes. Children with learning disabilities may also
be more susceptible to the negative effects of chronic noise exposure.
A recent study by Evans & Maxwell (1997) identified a link between chronic
noise exposure and reading. The noise source was a nearby airport; planes
flew over the school on an average of every 6 minutes resulting in
classroom decibel levels of 90. In this study children in the noisy school
had poorer reading skills than children from the quiet school. The noisy
school children also were not good at distinguishing speech masked by
white noise but were able to distinguish specific sounds (e.g., cat
meowing, baby crying). This finding suggests that there is selective
screening out of auditory stimuli by children in chronic noise settings.
Another possibility is that speech is used differently in noisy settings
than in quiet settings and children miss learning certain language skills.
Nevertheless language skills related to speech seem also to be related to
reading skills. It is worth noting that the attentional research also
found that noise interfered with children's discrimination of speech. All
children were tested in quiet conditions in this study thereby confirming
that chronic noise, and not acute noise, is related to academic
achievement.
Current study (Maxwell & Evans)
The finding that certain language skills are related to reading skills
and that noise is related to both led us to look at when these skills are
being acquired. The current study looked at 4 year old children attending
a day care center. In this study the noise source was the classroom itself
due to the design of the center and classrooms. Ceiling were very high and
no sound absorbent materials were used. Some classroom walls were not
floor to ceiling thereby allowing noise from adjacent spaces to drift in.
Teachers and administrators had identified the noise as excessive and had
made arrangements to reduce the noise. Children were tested in as quiet
conditions as possible before and after the noise abatement (sound
absorbent panels installed in the ceiling). Several measures of
pre-reading language skills were used. Teachers also rated children on
their language skills.
The before and after decibel levels in the classrooms were:
Before
Peak: 96.8 - 99.1 dBA
Average: 69.4 -
73.9 dBA
After
Peak: 87.2 -
95.2 dBA
Average: 75.8 - 77.1 dBA
In the quieter condition (note that decibel levels are still high - EPA
recommends no higher than an average of 70 dBA) children were rated by
their classroom teacher as having better language skills (e.g., child
speaks well enough to be understood by others, child uses sentences, not
just words) and the children performed better on a cognitive language
skills measure.
The researchers were also interested in motivation since there was
anecdotal evidence from the teachers that noise was affecting children's
desire to participate in activities (other research supported this
observation by these teachers). Children were given two puzzles, one could
not be solved (given first) and the other was solvable. Children in the
quiet condition took significantly less time to complete the solvable
puzzle. Perhaps children in the quieter classrooms had better attentional
skills enabling them to solve the puzzle quicker.
Implications for child care center design
Preschool classrooms (children ages 3-5) in four other child care
centers were visited (2 in New York City, 2 in Ithaca, NY) to compare the
noise levels and classroom design to that of the center in the study
described above. In the classrooms with some soft surfaces (carpeting,
pillows, curtains) noise levels were lower (average 65 -71 dBA). In
classrooms with all hard surfaces and concrete columns dividing spaces the
average noise level was 78 dBA with a peak of 90 dBA. Classrooms without
buffers between them also generated more noise. A buffer could be a
corridor or a wall. Adjacencies are also important. If common multipurpose
spaces are located adjacent to classrooms, particular attention should be
paid to acoustical design.
Ceiling heights are critical as well. In the center where the study was
conducted ceiling heights were in some areas over 14 feet. While these
heights created interesting looking spaces, they were problematic in terms
of noise levels.
Conclusion
Chronic exposure to noise has been shown to be harmful to children of
various ages. It can have especially detrimental effects on younger
children when language and discrimination skills are forming. Sometimes
major noise sources are not in the control of teachers or designers.
However, as this study documents, sometimes the noise source is the design
of the spaces. Designers should keep in mind the use of the spaces they
are creating. In child care centers, spaces must allow for the fact that
children need to make noise but the subsequent noise levels should not be
harmful to them or others in the center.
Lorraine E.Maxwell, Ph.D.
Assistant Professor
Design & Environmental Analysis
Martha Van Rensselaer Hall, E310
Cornell University, Ithaca NY 14853-4401
References
Evans, G.W. & Lepore, S.J., (1993). Nonauditory effects of noise on
children: A critical review. Children's Environments, 10(1), pp.31-51.
Evans, G.W. & Maxwell, L., (1997). Chronic noise exposure and reading
deficits: The mediating effects of language acquisition. Environment and
Behavior, 29(5), pp.638-656.
Kryter, K.D., (1985). The effects of noise on man. New York: Academic
Press, Inc.
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