Psychological Methods for Environmental Study Psychological procedures relevant to environmental ques-tions can be conveniently divided into the following catego-ries: studies of senso
Trang 1Man’s interaction with his environment is an integral part of
the science of psychology Psychology has been defined as
the study of human and animal behavior Behavior does not
take place in a vacuum It is conditioned by the environment
in which it occurs
The relationship between man and his environment is
interactive Man is not only influenced by his environment;
his behavior may also profoundly affect his environment
Where psychology can predict behavior for various
environ-ments, it will permit calculation of the impact of behavior on
the environment To the extent that it has developed
proce-dures for controlling such behavior, it can alter the impact of
human and animal behavior on the environment by changing
that behavior
Viewed from this perspective, psychology might be
expected to have far reaching impact on any area of
environ-mental concern; indeed, for any area of human concern
It is not surprising then, to find that much work in
psy-chology is relevant to problems of concern to
environmen-tal scientists and engineers Problems in almost any area of
environmental study may have roots in psychology Many
substances whose physiological effects are of concern to
environmentalists first make their effects on organisms
apparent through behavioral indices and tasks studied by
psychologists Many standards problems have
psychologi-cal aspects Potable water must be acceptable to the palate,
as well as meeting biological and chemical standards based
on health considerations It has been shown that existing
ventilation standards for inhabited buildings originated in
part from considerations of odor control The impact of a
field depends upon its achievements, as well as its domain
of concern, however One of the aims of this paper will be to
consider the extent to which psychology can accomplish its
aims in areas of environmental interest
This paper will concern itself first with psychological
studies relevant to man’s physical environment It will then
go on to consider his psychological and social environment
These categories are to some extent artificial The relevant
environment for an organism consists of those aspects of the
physical environment to which it is sensitive This
environ-ment is not necessarily the same as the physical environenviron-ment
as measured by physicists or engineers A colorblind organism
will not respond to variations in the wavelength of light in the
same way as one with color vision, though the physical
stimu-lus is the same in both cases Psychophysics is the branch of
psychology concerned with the relationship between man’s
sensory processes and his physical environment and over one hundred years of psychophysical research has shown that the relationship is both subtle and complex Nevertheless, such division conforms to some natural boundaries within the fields
of psychology, and of environmental studies, and so it will be adopted here
THE PHYSICAL ENVIRONMENT
The earliest studies in psychology were concerned with the relationship between measurements of the physical environ-ment and perceptual processes Since one cannot determine the nature of a percept directly, what was actually measured were certain observable responses, which were taken to be indices of these percepts Although the concept of behav-iorism was not originally enunciated in connection with psychophysics, but came later in connection with studies
of learning, it is well to note that problems in all areas of psychology can be formulated in behavioral terms In the author’s opinion, this should always be done It avoids innu-merable arguments over concepts and processes if one rec-ognizes that only the behavior is measurable, and that other concepts, such as motives, feelings, images, etc., are, from this point of view, theories developed to facilitate description
of the relationships between the environment and behavior, however real these constructs may seem in other contexts
Psychological Methods for Environmental Study
Psychological procedures relevant to environmental ques-tions can be conveniently divided into the following catego-ries: studies of sensory thresholds and simple perceptual and psychomotor tasks; behavior in simple learning situations;
more complex-learning and decision tasks; methods for studying opinion; and evaluation of such complex processes
as emotion and personality changes in response to environ-mental factors
Psychophysical Procedures The study of sensory
thresh-olds is one of the oldest areas of psychology, going back
to the work of Weber and Fechner towards the end of the nineteenth century Classically, two types of thresholds have been determined; absolute thresholds and difference thresh-olds The absolute limen, or threshold (AL) is the minimum amount of stimulus energy required to elicit a response;
the difference limen (DL) or threshold, is the minimum
Trang 2energy change required to perceive a change in the stimulus
Because the amount of energy related to that required for a
perceived change is often related to the absolute value of the
stimulus, the different limen is often given as a fraction of
the absolute value
Since the range of intensity for most of the senses is very
large, it is customary to use a logarithmic scale in expression
of the stimulus values In audition, the decibel is a common
unit Intensity ( I ) is given in decibels (dB) by
I⫽10logP P1/ dB,r
where P 1 is the stimulus power, and P r the reference level
Measurement in decibel units is less common for the other
senses, but some type of logarithmic scale is frequently used
The measurement of thresholds presents certain
techni-cal problems, due to variability in the response, and the
pos-sibility of response bias Two major methods were devised to
deal with the problem: the method of limits and the method
of average error In the method of limits, series of stimuli
of varying intensity are presented and the subject is asked
to make a response, according to whether the subject does
or does not perceive the stimulus, or stimulus change Since
threshold values obtained typically depend on whether the
approach to the threshold is up (from unperceived to
per-ceived) or down (from perceived to unperper-ceived), several
series of trials in both directions may be averaged The
method of average error is an adjustment method The
sub-ject is asked to adjust a variable to match a standard, and the
variability of the response is used as a measure of the limen
It is most suitable to difference limen measurements
Recently, the concept of a sensory threshold has been
questioned, and the most popular view at present is to view the
internal process as continuous, with a criterion applied to
pro-duce a dichotomous response The view derives from the signal
detection theory of sensory processes The extent to which this
model of the threshold differs from older ones is arguable; the
arbitrary nature of the threshold concept has always been
rec-ognized However, it has led to a more systematic treatment
of the problems of noise and bias in threshold measurements
Procedurally it stresses the measurement of thresholds by
yes/no judgments in which the probability of a false alarm is
explicitly estimated, and by forced choice techniques Receiver
operating characteristic (ROC) curves are used to analyze the
data The resulting measure of sensitivity is usually referred
to as d From the point of view of reliability, either the classic
methods or new signal detection procedures will usually lead
to satisfactory results
The sensory dimensions have been divided into two
types: intensive dimensions and qualitative dimensions
Examples of intensive dimensions are the intensity of light
and sound Examples of qualitative dimensions are color
and pitch, which often have recurrences in them, such as the
scale relation in pitch, which complicate analysis Sensory
intensity normally increases logarithmically with increases
in the physical stimulus Qualitative dimensions may have
more complex relationships with their physical correlates
The measurement of sensory thresholds may be extended to animals by means of conditioning procedures to be described
in the next section
Several thresholds other than the absolute and differen-tial limens are important for environmental studies Often, concern will lie in thresholds for discomfort, and for toler-ance It may also be desired to obtain information on the degree of discomfort produced by different environmental conditions Direct judgments of discomfort or tolerance tend
to be highly variable; individual tolerances, or at least state-ments about these tolerances, differ from individual to indi-vidual One technique which is sometimes used is to obtain comparison judgments about the relative discomfort caused
by different stimuli One method of measuring pain thresh-olds is based on this principle; the discomfort caused by var-ious stimuli is compared with the pain caused by a known exposure to infrared light on the forehead
A fixed standard need not be used; cross comparison
of the set of stimuli of interest is possible Techniques have been developed for taking such paired judgments, and using them to scale the stimuli along the dimension of judgment
Variations of this technique can be applied to ranked data:
ranking is less time consuming than a full set of paired comparison judgments, but it requires more assumptions to generate a scale Multidimensional scaling techniques are usefully applied to preference or similarity judgments, how-ever obtained They are especially useful where the relevant dimensions of eth stimulus set are not clear, since they can
be analyzed to obtain dimensions of judgment It is also pos-sible to analyze such judgments for clusterings among the subjects
Classical and Operant Conditioning Classical condi-tioning is a type of learning pioneered by I Pavlov, and still extensively studied by psychologists In its simplest form, the procedure consists of presenting some stimulus which consistently elicits a response, known as the unconditioned stimulus (UCS) in combination with some other stimulus which does not normally evoke the response, known as the conditioned stimulus (CS) After a number of trials, the CS will be found to elicit the response in the absence of the UCS
Such a response is known as a conditioned response (CR)
Various complexities can be introduced into this para-digm and it has been the subject of extensive study and theoretical discussion Its primary importance for the envi-ronmental field lies in the fact that the technique can be used
to determine sensitivity to various stimuli This can occur in two ways
1) The effect of various physiologically active stim-uli on the course of acquisition and extinction of a known CR can be studied Changes in the course
of learning and extinction are evidence of the effect of the stimulus
2) The procedure can be used to determine threshold sensitivity to a stimulus If a CR can be established
to a given concentration or intensity of a stimu-lus, it is evidence that the organism is sensitive to the stimulus, though the reverse is not necessarily
Trang 3true Thus, classical conditioning techniques can
be used to measure sensory thresholds in animals
A second major type of conditioning is known as
oper-ant conditioning In operoper-ant conditioning, there is nothing
equivalent to the UCS; a response which occurs is
fol-lowed by some subsequent event, such as the occurrence of
food, which will modify the frequency of the response The
desired response may have a low probability of occurrence
and procedures such as shaping and the creation of special
environments may be necessary Shaping consists of
rein-forcing successively closer approximations to the desired
response A common example of a special environment is
the Skinner box, a small enclosure whose most prominent
feature is the response mechanism, usually a bar or button
The rat or pigeon in a Skinner box, pushing a bar or
peck-ing or at a lever to obtain food or avoid electric shock are
example of operant conditioning situations
Operant conditioning procedures can be used for the
same purposes as classical conditioning methods, but they
have some advantages Classical conditioning is relatively
difficult to establish, is easily disturbed by any change in
the environment and the CR ceases to occur (undergoes
extinction) rapidly once the UCS is removed Operant
con-ditioning, on the contrary, is relatively easy to establish
One reinforcement often makes a marked difference in
response rates It is less sensitive to extraneous
environ-mental interference and it can be maintained for long
peri-ods of time with a very low reinforcement rate Records of
cumulative responses to various reinforcement schedules
show definite regularities Changes in these patterns
pro-vide a sensitive measure of the effect of various chemicals
on behavior and have been extensively used for this
pur-pose in drug research Threshold measurements in operant
conditioning require a slightly more complex situation than
in classical conditioning if the substance to be studied does
not act as a reinforcer of behavior However, by using it as
a cue to indicate when some positive reinforcement is to be
given, the thresholds of such substances can be studied by
operant techniques Both operant and classical
condition-ing techniques are applicable to humans as well as other
organisms
Other Simple Learning Situations Other types of
learn-ing situations which have been studied sufficiently to provide
a basis for the study of behavioral effects of
environmen-tal factors are maze learning, discrimination learning, and
a variety of simple verbal learning tasks The former tasks
may be used with either humans or animals The verbal tasks
are limited to humans The complexity of the stimulus
situ-ation is generally greater in these tasks Specifying the
rele-vant dimensions of even simple mazes for learning situations
is complicated, and an enormous and continuing effort has
been devoted to the study of the features of verbal stimuli
which affect simple learning tasks such as paired associate
learning (where people are presented with pairs of words and
then asked to recall one of the words when shown the other)
and serial learning (where subjects are asked to learn lists of
words) They are therefore less easy to quantify and compare
across experiments than are conditioning responses and thus introduce additional problems for the study of environmen-tal effects However, with sufficient care, reliable measure-ments can be obtained
These tasks come closer than simpler tasks to being of
a complexity relevant to behavior in real life situations It
is quite possible that some stimulus will have no measur-able effect on a simple process, but will effect more complex behaviors; the reverse is sometimes also the case; environ-mental conditions which will affect simple and monotonous tasks may not affect more intrinsically interesting tasks For this reason, learning tasks other than simple conditioning are often studied when the effects of various environments are under investigation
More Complex Tasks The number of human perfor-mances which have been studied by psychologists is very large; no satisfactory classification has been worked out for procedures going beyond the simplest Various bases for cat-egorization have been proposed; for example, sensory-motor
to verbal, depending on the type of response; or in terms of complexity, from simple conditioning to complex problem solving Probably the best ultimate solution will consist of
a task analysis for more complex behaviors in terms of their dependence on more simple processes, but this has not been achieved in any general way at present The particular type
of task employed and the dimensions along which it is to
be analyzed can be best considered at present in terms of the particular experimental situation If an investigator is concerned with the effects of certain pollutants on complex judgments required by some task, he will do well to con-struct a task as much like the criterion task as possible and test the effects by means of a suitable design If his concern
is with performance in a vigilance situation, then a vigilance type task should be selected Generalizations from effects on simple behaviors to more complex behaviors are hazardous
at present
Standardized Tests of Behavior Standardized tests have
been developed for a wide variety of human abilities IQ tests are the most famous, but many others exist Such tests have
as their primary purpose either selection in connection with personnel work, or evaluation for counseling for guidance, but they may be used in the same way as other tests for the evaluation of the effect of environments on performance
Tests of this sort may be divided into tests of general ability, tests of specific ability, and tests of personality Both
of the former have been used in connection with environ-mental work Occasionally, the latter have been also, though their suitability for the purpose of evaluating temporary shifts in emotional state is often dubious Most standardized tests are designed to measure some relatively permanent characteristic However, some of these characteristics, such
as various types of manual dexterity, are sensitive to various environmental forces in a fairly straightforward way The effects of depressant drugs on personality tests are consid-erably less clear There is also a serious problem of valid-ity with regard to some tests, especially personalvalid-ity tests
The objective tests, such as the Guilford-Zimmerman or the Minnesota Multiphasic Personality Index (MMPI), have
Trang 4been extensively validated against certain criteria, such as
psychiatric diagnosis However, the criteria themselves are
open to argument in many cases Also the criteria used for
validation are seldom those of interest if a test is to
mea-sure temporary changes in emotional state due to changed
environment The tests often appear likely to be insensitive
to the types of mood changes which may be of interest to
environmentalists Projective personality tests appear, on the
surface, to be more sensitive for this purpose, for they permit
much freer response than objective tests, and they have been
used, for example, in studies of aggression However, they
are exceedingly difficult to validate, even against the type
of criteria used for objective personality tests, and their
pre-dictive value for other types of behavior is almost entirely
unknown
Comments on Psychological Methods In evaluating these
procedures for use in the environmental field, there are some
general considerations to keep in mind First, the
psycho-physical procedures are generally reliable, if carefully done,
and generalization to other individuals from a small sample
is good This work is often done with two or three
observ-ers, and the results are repeatable The extreme sensitivity of
the sensory systems means that very precise control over the
stimulus is needed, which is often expensive Certain
stim-uli, especially odors, are difficult to handle; special
equip-ment, such as odorometers, is necessary Timing down into
the millisecond range is typically needed in visual and
audi-tory experiments
Other types of behaviors tend to be more variable Only
in simple conditioning situations are such small numbers of
experimental subjects likely to be found, and even here, for
most purposes, more than three or four subjects are
neces-sary The requirements for stimulus control are somewhat
less rigid, in most cases In verbal learning studies, timing
to 01 sec is usually adequate; less precision is often
toler-able However, the substantial variability of organisms
presented with even relatively simple learning tasks, such
as mazes or simple discrimination learning, makes a larger
sample desirable Individual experimental conditions may
be tested on 10–12 subjects, or more; it is not uncommon to
find verbal learning experiments which use several hundred
subjects Generalization to other populations is sometimes
more of a problem and the equivalence of stimuli in different
experiments is more difficult to establish However, within
these limitations, reliable results can be obtained in simple
conditioning situations and most other simple learning tasks,
including simple verbal learning tasks
Both classical and operant conditioning procedures are
very sensitive to the action of certain agents Effects of levels
of ionizing radiation have been reported as low as 5.0 r in
con-ditioning experiments Behavioral effects of several drugs of
environmental importance, such as alcohol and amphetamines,
can be found for relatively low dosages While the
informa-tion on the sensitivity of condiinforma-tioning procedures to agents of
interest such as SO 2 and NO 2 is sparse, there is no reason for
believing that behavioral measures will not be equally
appli-cable to many of these substances Behavioral studies done in
Russia emphasize the use of classical conditioning techniques
in studying various environmental factors In such research behavioral effects for low levels are frequent, though it is dif-ficult to evaluate due to the obscurity of much of this literature
by American standards of reporting
Problems arise when it is desired to interpret behavioral measures in a more refined fashion than simply as indicators
of some physiological activity of the substances Temporary threshold shifts from noise exposure have been extensively investigated, but their implications for permanent damage is still being debated (see Noise) Similar problems exist for other measures The problems which have faced psycho-pharmacologists in interpreting effects of drugs on animal behavior in terms of drug effects on humans have their coun-terpart in the environmental field; granted that a certain level
of ionizing radiation can serve as an aversive stimulus in operant conditioning experiments on saccharin preference, for example, how are the results to be interpreted in terms of public health standards? How long lasting must such effect
be in order to be indicators of possible physical damage? If
no physical damage is to be expected, there is still the ques-tion of the costs of possible funcques-tional impairment Does impairment of operant conditioning imply that the agent will also impair more complex functions in humans, with a pos-sible increase in errors or accidents as the result? At present, answers are not available to these questions
More complex tasks raise more serious problems of reli-ability It is not uncommon in educational research for several experiments to yield contradictory results, for reasons which are often obscure The complexity of the materials and other variations in subjects and procedures which are difficult to control or characterize are probably responsible Thus, a single study done on the environmental effect of a substance
on complex learning should be viewed with caution Only when a series of experiments done under varying conditions converge on a result should the result be accepted
Certain special problems which often arise are the effects of novelty (the so-called “Hawthorne” effect) and habituation effects Individuals may perform well under a certain test procedure, which, when put into practice proves
no better than the alternative The problem is that subjects
on whom new procedures are tried may make a special effort which is not sustained under routine conditions A similar effect arises in regard to habituation Individuals may respond badly to a new environment, but adjust to it over time without final decrement in performance Since adapta-tion for some tasks can take months, adaptaadapta-tion effects are often inadequately tested
Most research involving the possibility of exposure
to physically hazardous conditions is done on animals
However, a good deal of research which involves physical discomfort or emotional stress is done on humans Also, in some research, personal information of a private nature may
be obtained Concern over possible abuses of subjects has arisen in recent years, and several professional societies have
or are developing codes of ethics to deal with these prob-lems There are also legal aspects to the use of human and animal subjects of which any potential research worker in these fields should make himself aware
Trang 5THE PHYSICAL ENVIRONMENT AND BEHAVIOR
Sensory Processes
Judged purely in terms of their adequacy as detectors,
sen-sory systems are very efficient for many types of stimuli The
auditory system, for example, is capable of detecting sound
near the level of Brownian motion under suitable test
con-ditions The number of photons required to obtain a visual
response has been estimated as low as 5–14 photons under
optimal conditions The olfactory system is also exceedingly
sensitive As has been noted, the intensity of a sensation goes
up approximately as a logarithmic function of increases in
intensity of the physical stimulus (the Weber–Fechner law)
It applies to such sensory domains as vision, audition, etc
In specific applications, of course, this information is
inad-equate for most purposes and more precise information is
needed The apparent loudness of a noise will depend on its
frequency as well as its intensity, for example
When qualitative factors are under consideration, it is
more difficult to make any statements The annoying
prop-erties of a noise are a complex function of specific
com-binations of frequency and intensity and it is still not well
understood See the article on noise in this volume for a
more complete discussion of this problem
There are, however, a few general statements about
sen-sory systems which may be of use to environmentalists First,
of course, the primary channels of information to human
beings are the visual and auditory systems Senses such as
touch, taste, smell, and so on are of far less importance than in
the case of many animals Of the major channels, vision has
the larger channel capacity, in the information theoretic use of
that term However, this is not equivalent to an expression
of their social importance The auditory channel is the primary
means of face-to-face communication between human beings,
and studies indicate that loss of hearing may produce more
profound personality changes than loss of vision Early loss of
hearing can produce a disastrous effect on language learning
For many purposes in adults, they may be equivalent for
infor-mation transmission When one is dealing with tasks which
are purely informational, the visual channel may be more
effi-cient, since in tasks like reading, humans can process more
words than they can listen to in a given period of time
Knowledge of visual and auditory parameters is important
in the proper design of a number of environments Consider
the hazards associated with sources of glaring light along
high-ways at night, for example The visual system adapts relatively
rapidly (usually within a minute) to large increases in light
The process of dark adaptation is much slower, however; it
may take as long as half an hour to fully dark adapt the visual
system Rapid changes in the external light levels at night can
therefore constitute a hazard, since they may keep the eyes of
drivers in a state of adaptation to relatively high illumination
levels even though the average level is relatively low
Effects of Various Pollutants on Behavior
Ionizing radiation Perhaps the pollutant whose behavioral
effects have been studied most extensively is ionizing
radiation Studies on both lethal and sublethal doses of both particulate and non-particulate radiation have been done The conclusion has been that there is relatively little effect of either on the learning behaviors for most organ-isms Insofar as tests are available, this seems to be true of man also However, the activity levels of young rats have been reported to be affected when the mothers had been irradiated with one dose of 200 r during pregnancy
This does not mean, however, that organisms are not sensitive to radiation Radiation has been used to condition avoidance to a saccharine solution (normally preferred by rats) It was found to produce an 80% decrease in response rate under some conditions The amount of the decrement has been shown to be dose dependent Russian research, using classical conditioning techniques, has reported a variety of behavioral effects, occasionally for doses as low as 5 r
Air Pollutants The effects of carbon monoxide (CO) on
behavior have received a good deal of study Among other effects, 90 min of exposure to 50 ppm CO has been shown
to impair ability to discriminate among relative lengths of short time intervals The effect of CO on the electroen-cephalogram (EEG) patter in rats has been investigated The results suggest a possible depressive effect of CO on central nervous system function Significant reductions in tests of manual dexterity have been observed with blood carboxy-haemoglobin (COHb) levels in excess of 25%; such levels may be reached in garages and other enclosed areas con-taining motor vehicles CO is known to elevate the visual threshold
Since CO and some other pollutants have as one of their effects the reduction of the oxygen level in the blood supply, studies on the effects of hypoxia (oxygen deficiency) are relevant to the behavioral effects of gaseous pollutants
The visual threshold is very sensitive to hypoxia; significant impairment can occur at altitudes as low as 5000 ft, and at 15,000 ft twice as much light is required for minimum vis-ibility as is required at sea level Auditory and speech per-ception thresholds may also be affected slightly, especially for long exposures Tasks requiring complex coordination, such as handwriting, deteriorate above 10,000 ft, and higher altitudes can affect simpler tasks and reaction times Various cognitive tasks, such as card sorting, are affected, usually more than simple psychomotor tasks
The physiological effects of a number of other pollutants such as NO 2 and SO 2 have been studied and information about their olfactory effects is also available The olfactory system
is very sensitive, and may give adequate warning for some pollutants Sulfur dioxide, though extremely toxic is difficult
to inhale at lethal concentrations without warning because
of its intensely irritating properties Habituating effects do occur with repeated exposure, however, and severe poison-ings have occasionally been reported among workers who have adapted to high levels of this pollutants It is important
to note that the olfactory sense adapts very rapidly to most odors This consideration is important when using odor tests, for chlorine in water, for example
A number of other substances are not readily detect-able by smell, however Carbon monoxide is odorless, and
Trang 6nitrogen dioxide can cause fatal poisoning at concentrations
which are not physically annoying
Other Chemical Pollutants The behavioral effects of a
number of other chemical substances which may be of
environ-mental significance have been studied These include alcohols,
various psychoactive drugs, and various industrial chemicals
Ethyl alcohol has been found to increase reaction time by about
10% when the level of alcohol in the blood reaches 0.35%
Blood alcohol levels of 100 mg/100 ml have been reported to
affect monitoring and tracking tasks, and lower levels have
been reported to affect various complex tasks
It has been possible to study the effects of a number of
such chemicals in conditioning experiments Several drugs
have been shown to increase eating or drinking behavior in
animals; these are usually drugs which act to reduce anxiety
Meprobamate and similar drugs usually increase eating; the
barbiturates chiefly affect drinking A number of such drugs
have been shown to produce decrements in escape or
avoid-ance conditioning, an effect usually attributed to their fear
or anxiety reducing properties Morphine addiction can be
induced in animals, and the drug can serve as a positive
rein-forcer for behavior, permitting the study of various aspects
of addiction, such as withdrawal, in animals, using
condi-tioning concepts and procedures
Depressant drugs, such as the barbiturates, have
gener-ally been found to impair memory in humans Retrograde
amnesia (failure to recall events just before administration
of a drug or some traumatic incident, such as a blow to the
head) has been reported for ether and for CO 2 , administered
post-trial However, conflicting evidence exists Post-trial
administration of ether can also facilitate retention, and 30%
nitrous oxide has also been reported to facilitate retention in
humans when given after learning, though other studies have
found impairment with nitrous oxide
Facilitation effects on memory have been reported for a
number of other drugs Strychnine has been shown to improve
maze learning for food rewards, discrimination learning, and
other tasks Various other substances have also been studied
However, the results are conflicting at present
The various effects of chemicals on retention have been
interpreted in various ways It has been hypothesized that a
certain period of time is necessary following learning for
con-solidation of the memory trace Drugs or other events, such as
a blow on the head, or the administration of electroconvulsive
shock, may interfere with this process and prevent the
reten-tion of learned responses over time Other possible
explana-tions lie in facilitation or interference with nerve transmission
or with protein synthesis The inhibiting effects of
puromy-cin and other antibiotics on some learned responses has been
attributed to their interference with protein synthesis, though
other explanations are possible Explanations in terms of the
drug effects on the animals’ perception of the cues in the
learning situation have also been suggested
Environmental Stressors
Unusual conditions of temperature, noise, lighting, vibration,
etc may be encountered in some environments Extreme values
of such stimuli are often regarded as environmental stressors, and their physiological effects have been extensively studied
Concern has also been felt about their behavioral effects, and
a number of studies have been done on this question
Noise Excessive noise levels are known to be capable
of damaging the auditory system Noise can also be annoy-ing, and its annoying properties are a complex function of its spectral composition (see Noise) It can also seriously interfere with tasks which depend on auditory communica-tion However, studies of effects on non-verbal tasks have reported mixed results, often negative While interference through distraction may occur with sudden unpredictable sounds, in general, noise seems to have a minimal effect on most non-verbal tasks It should be kept in mind, however, that adapting to noisy environments may impose additional stress on the organism Noise can induce audiogenic seizures
in susceptible strains of rats, and there have been reports of sound-induced seizures in epileptics
Temperature A number of studies have shown
decre-mental effects of elevated temperatures on a variety of tasks
Telegraph operators who had been acclimatized to a hot envi-ronment (Singapore) were studied at several temperatures above that of their usual environment Errors were found that were related logarithmically to the temperature increase
in the receipt of coded messages made up of assorted letter and number strings Similar results have been reported by artificially acclimatized subjects in England Subjects’ judg-ments of comfort are not necessarily reliable guides to the temperature which gave best task performance In general, the relationship between behavior decrement and heat stress
is more straightforward for tasks involving physical effort than for other tasks, but effects on both have been reported
Cold has also been studied, chiefly in relation to its effects on manual dexterity, which it decreases Adaptation effects are also reported to cold
Studies have been reported which show decrements
in learning and retention with elevated temperatures, and improvements with cold environments The latter have mostly been reported with invertebrates, and it is unclear whether the effect is directly temperature related, or due to restriction of activity with cold
Vibration Excessive vibration has been shown to be
physically damaging, especially to the circulatory system,
in addition to causing symptoms such as seasickness in susceptible individuals In terms of effects on other behav-iors, the chief effect has been shown on visual acuity; most other studies have reported other behaviors to be unaffected
However, vibration has been reported to be unpleasant, if prolonged, even though the levels are below those believed
to cause physiological damage, and secondary effects might
be expected on monotonous tasks The vibrations studied have varied from 0–60 Hz, these being the range of practical interest for most environmental purposes Interactions with frequency are known to exist Frequencies in the range of 10–24 Hz most severely impair visual acuity, while manual tracking is most seriously affected at frequencies of about
5 Hz This frequency also produces the greatest subjective discomfort
Trang 7Inadequate Lighting Lighting may be inadequate either
because it is too low, or because it causes glare Excessive
light intensities, such as those generated by lasers, can cause
physical damage to the eye While the eyes can adapt to a
wide range of light conditions, the thresholds of the
phot-opic receptors in the fovea of the eye are higher than in the
periphery (scotopic vision) The density of receptors in the
fovea is also higher, and the functioning of these receptors is
important for tasks requiring good visual acuity Therefore,
if the light levels fall below the photopic threshold, such
tasks will suffer Visual acuity may be tested by means of
Landolt rings (circles) with small breaks whose orientation
the subject must detect) or by means of grids of varying
fine-ness and orientation Effects of light composition have also
been shown on some tasks, even well above the photopic
threshold For most visual tasks, light levels well above the
photopic threshold should be maintained
Glare causes discomfort, and may interfere with
vari-ous tasks Two kinds of glare are distinguished; direct glare
from a light source in the visual field; and specular glare due
to light reflected from surfaces within the visual field Both
types of glare can be controlled by suitable adjustment of
the environment Direct lighting offers maximum light at the
working surface when the source is directed downward, but
it is likely to produce shadows, glare and undesirable
bright-ness contrasts Indirect lighting avoids these problems, and
while it may lessen visual efficiency in reading over very
prolonged periods, it has been shown superior to direct
light-ing in tests of 3 hr in length
It should also be realized that color vision depends on
the receptors in the fovea Therefore, tasks requiring the use
of colors must be performed with adequate lighting The
color of surfaces depends on the spectrum of the light which
falls on them, so illuminants must be chosen to provide the
proper colors for tasks involving color coding
Special Environments
Changes in Sensory Input Early reports on the effect of
iso-lated environments from polar expeditions and the like are in
agreement with later experimental findings on the
undesir-able effects of restricted sensory inputs Studies on extreme
sensory restriction as carried out at McGill University,
where subjects wore translucent goggles and stayed in low
variability environments, have shown that such effects as
loss of ability to concentrate and hallucinations may result
Polar expeditions have reported compensatory behavior in
the form of the development of unusually structured groups,
and special interests and hobbies on the part of individual
members Similar patterns sometimes develop in such
isola-tion situaisola-tions as solitary confinement
Studies on early sensory restriction in animals have
sug-gested that deficits of varying degrees of permanence may
develop in subsequent behavior as a result Extreme
depriva-tion of sensory input and social contact is known to result in a
variety of deficits in human infants, even though the physical
needs of the infants have been met The monotonous effects
of long periods at tasks such as monitoring sonar screens
for infrequent signals, and other vigilance tasks have shown deleterious effects in terms of missed targets
The effects of excessive sensory input are less clear Any situation which overloads the information processing capac-ities of an individual will be likely to result in decremental performance However, apart from such short-term effects,
it is not clear that there are long-term effects from an overly complex environment
The reticular activating system in the brain stem, which has been shown to have an alerting effect, has been sug-gested as a possible locus for some of the effects of sensory isolation
Other Special Environments Some other special
environ-ments that have received a good deal of study are submarines and simulated space capsules The outstanding feature of the submarine environment is its limited space Most studies have focused on physical problems associated with this envi-ronment, but a few have been concerned with the psycho-logical effects In general, adaptation to crowded conditions
is seems to be good, though there are some losses of person-nel attributed the confined conditions One study reported
a loss of 7% of 187 men over 6 months due to this factor
Complaints about lack of privacy have been reported also
The problem of diurnal cycles arises in connection with such environments The usual night–day shifts are lacking,
of course, in extended undersea cruises, and time confusion has been reported: for example, inability to remember if it is 8.090 a.m or p.m It has been found desirable to introduce features, such as news reports and evening entertainments, into the daily routine which will avoid the sensation of being cut off from the rest of the world and which serve to mark diurnal cycles It also appears that, although such cycles can be influenced by the environment to some extent, there are limits to the process Alluisi reports evidence of diurnal cycling in performance under a variety of work–rest sched-ules, including some as extreme as 4 hr of work followed by four of rest
Simulated space capsule environments have many of the features associated with sensory deprivation conditions, plus the added factor of fatigue Prolonged exposure to such environments has been shown to produce decrements
in a number of tasks, from vigilance tasks to complex deci-sion making functions Diurnal rhythms in efficiency have also been reported However, it has also been found that trained pilots, who were familiar with the concept of diurnal rhythms, did not show such effects Both motivational and adaptation processes may be at work here It has been shown repeatedly that measures of “can” and “will” are often very different for special environments
Diurnal cycles may be important in less exotic environ-ments Efficiency in a number of tasks has been shown to vary with the diurnal cycle These variations appears to be related
to the body temperature, which reaches its lowest point after several hours of sleep, and does not reach its maximum until the evening of the next day These variations create prob-lems for jobs with several shifts, since operator efficiency is constantly varying While individual cycles show adaptation
to changes in times spent awake and asleep, this adaptation
Trang 8takes time, so that several days may be required to adapt
fully to a change in shift
THE DESIGN OF ENVIRONMENTS
This section will be concerned with the design of physical
environments for maximum human comfort A later section
will be concerned with psychology’s role in the design of
environments in a broader sense, as in urban planning
A great many human engineering studies have been
done on special environmental problems Anthropometric
measurements have been gathered to facilitate the design of
objects used by humans, and a great deal of information is
available on the integration of this information with special
problems, such as designing handles for use with gloves
Information about the size and movement of various parts of
the body are important to proper design of a wide variety of
furnishings and equipment, from chairs to work areas
The proper display of information is another important
aspect of proper environmental design Studies have shown
that certain types of dials are read more easily than others
Airplane roll indicators which used a fixed artificial horizon
with the position of the plane varying have been shown to
be more easily interpreted than indicators which keep the
plane steady and move the horizon, though the latter design
had been commonly used A good deal of information about
desirable features of scales has been obtained, and some
useful principles obtained For example, operators should
not have to transform information before using it Jet aircraft
tachometers, for example, may be calibrated in percentage
rpm rather than actual rpm so that the pilot need not
remem-ber the maximum rpm for different engines in order to
inter-pret the information
Many other factors go into the proper display of
informa-tion For example, if color coding is used, it must be
remem-bered that, while the visual system is able to discriminate
a very large number of colors, in the sense of being able to
say they are different if both are presented simultaneously,
the number that can be correctly distinguished when only
one is presented and memory must be used is far more
lim-ited The exact number will depend on the colors, viewing
conditions, and other factors such as training, but is unlikely
to reliably exceed ten in many situations and may be much
lower Knowledge of these and many other aspects of visual
and auditory perception are necessary for the safe and
effi-cient design of many facets of our environment
Another important problem is the proper integration of
human operators into complex man–machine systems Here
again, knowledge of man’s information processing
capaci-ties is important Such questions as the speed with which
an operator can respond, the probability of his detecting
warning signals under various conditions of display and
frequency, his tracking abilities with various displays and
types of targets, are merely samples of the types of questions
which arise and which have been extensively studied
It should not be assumed, however, that such
consider-ations are important only in military or industrial situconsider-ations
Proper design considerations are important for the safety and comfort of the consumer as well One study showed, for example, that different burner-control linkages on stoves resulted in different error rates even after a number of trails
Agreement among auto manufacturers on the arrangement of controls in cars with automatic transmissions is an example
of the importance of establishing conventions for the design
of widely used products The list of consumer products with features whose design will affect either comfort or safety is very long indeed
The information processing capacities of humans are important considerations in the design of any environment
The information processing capacities of any organism, including man, are limited In such areas of environmen-tal concern as urban planning, traffic control, etc., such considerations can be very important Man is capable of remembering enormous amounts of information, and per-forming feats of processing which defy the most complex machines, but his capacity for short term information pro-cessing is distinctly limited A large number of studies have been done on the problem of human attention and the effect of information over-loads on various performances
The results are quite consistent in showing very great limi-tations to man’s short term information processing capaci-ties Exceeding these capacities will result in more or less serious performance decrements For example, DAF (delayed auditory feedback) studies have shown that mis-matches in input information can greatly degrade perfor-mance Individuals have only a very limited capacity for responding to different information input simultaneously
to the two ears
Consideration of man’s information processing capaci-ties should be made in planning facilicapaci-ties for human beings
In particular, if new environments are being proposed, a very careful study should be made of their information pro-cessing demands However, concern should not be limited
to unusual environments Badly planned highway signs, which require a driver to attend simultaneously to too much information and make too many decisions too rapidly are
an obvious, and unfortunately all too common, example of failure to consider man’s information processing capacities
in designing the environment The adequacy of instructions and cautions in connection with the use of equipment or potentially hazardous substances may also require consid-eration of certain of man’s information processing capaci-ties Court cases have hinged on the adequacy of cautions regarding the use of equipment to inform potential users of hazards
There are psychological aspects to the design of larger aspects of the environment A classic study done on a stu-dent housing project at MIT showed that social groupings were significantly influenced by the physical arrangement
of the apartments Other aspects of modern building design may be important For example, most large modern build-ings are air-conditioned today Air conditioning may affect the ionic balance of the air and some concern has been felt that it may produce symptoms such as depression, though the evidence to date is inconclusive
Trang 9MAN’S SOCIAL ENVIRONMENT
Decisions made regarding the physical environment have
implications for social aspects of behavior, as we have seen
in the previous section In addition, some areas of
environ-mental concern, such as urban planning, must consider man’s
psychological and social environment more or less
explic-itly Population growth, for example, is greatly affected by
social attitudes, as the dramatic change in the birth rate in
Japan after World War II shows
The social sciences, including psychology, have roles as
information sources and in providing techniques for
imple-menting decisions about the social environment, especially
where these involve inducing changes in human behavior
patterns A vast amount of research has gone into the study
of social factors which influence human behavior, and much
of this information may be relevant in certain areas of
envi-ronmental planning Psychological techniques can be used
to gain information about people’s needs and preferences It
is not easy to design questionnaires which will provide
reli-able answers and many problems arise in obtaining
repre-sentative samples of the target population Psychologists and
sociologists have studied these problems extensively A great
deal is known today about proper sampling techniques for
such studies General answers to designing questionnaires
are more difficult to come by, but extensive experience has
provided some useful practical advice It appears likely that
many difficulties which have arisen in the past in
connec-tion with such matters as public housing in urban areas, have
been due in part to a failure to accurately assess the feelings
and concerns of those affected by such projects More
exten-sive use of survey techniques might eliminate some of these
problems
Certain reservations about research on man’s social
envi-ronment should be mentioned, however Large scale
experi-mentation is obviously very difficult to do, and so reliance
must often be placed on field studies Direct measurement of
behavior may be difficult, so recourse may be made to rating
scales and other indirect measures whose relation to actual
behavior is often uncertain Smaller scale experiments often
introduce varying degrees of unreality into a situation which
may make generalization to the real world situation difficult
While all of these comments apply in some degree to all
psy-chological research, they are especially apt to apply in areas
relevant to man’s social environment
Any discussion of man’s social environment must
also consider areas in which psychological techniques can
be employed to alter behavior Consider, for example, the
impact of problems such as crime, drug addiction, and so
forth on urban planning Informational aspects of these
problems certainly exist For example, what is the evidence
for a relationship between juvenile delinquency and housing
conditions? Such questions have been extensively studied,
and while the answers are still being debated, a great deal of
information is available on observed correlations
However, in addition to such informational aspects, the
question of the role of psychologists in dealing with such
ques-tions must be considered Plans must be made for dealing with
such problems, and this means that resources must be allocated
to them Obviously, the proper allocations must depend in part
on available options and their effectiveness It is therefore rea-sonable to ask what techniques psychologists have available for modifying behavior and to inquire into their effectiveness
A number of techniques, generally classified as psycho-therapies, have been developed to deal with neurotic behav-iors It is difficult to characterize these procedures in any simple way, since they have diverse theoretical roots and prac-tical implementation, but in general they depend on verbal interactions between therapist and patient to effect change
A number of variations on the classic one-to-one patient–
therapist relationship have developed in recent years Various forms of group therapy have developed In addition, sensi-tivity training procedures have been developed These are usually aimed at changing the behavior of those not consid-ered to be suffering from any personality disturbance, and they are likely to involve varying degrees of role playing and direct confrontation
The effectiveness of psychotherapies has long been a matter of debate and the question has not yet been resolved
Difficulties in evaluating them in regard to neurotic behav-iors stem from the high spontaneous remission rates, the dif-ficulties of diagnosis, and the problems of defining what is meant by a cure and determining when one has occurred
The record with regard to disorders such as psychopathic personality, drug addiction, etc., is even less optimistic Very little evidence of effectiveness is available, and many reports are discouraging
The situation is similar for sensitivity training procedures and group therapy While enthusiastic reports can be found,
so can negative reports Especially disturbing are reports of undesirable reactions to some kinds of sensitivity training, which can be rather aversive
To those familiar with other health areas, these problems
of evaluation may seem surprising Clinical research has a long history in medicine, after all, and while problems such
as placebo effects exist, methods have been developed to overcome them However, in addition to the usual problems associated with any clinical research, much of the research
on psychotherapies suffer from severe underlying problems associated with the entire concept of mental illness Szasz has gone so far as to deny the utility of the concept, and has developed some interesting analogies between the con-cept of mental illness and the concon-cept of witchcraft during the Middle Ages While his views are hardly universally accepted, it is clear that the problems go beyond the merely procedural
Behavior therapies, derived from conditioning techniques fare somewhat better Classical conditioning techniques have had some success with alcoholics, though problems exist
Operant condition techniques have been applied extensively
in the treatment of retardates, and have been used as the basis of token economies in mental institutions and homes for delinquents It is usually somewhat easier to evaluate the behavior therapies, in part because the specification of the procedures in terms of reinforcement contingencies pro-vides information about details of the process often lacking
Trang 10for other methods, and also because they focus on changing
behavior Such changes in behavior can usually be measured
directly, whereas changes in personality or emotional state
must be measured indirectly, and the appropriate tests are
often uncertain Behavior therapies are not invariably
suc-cessful, of course, and a current weakness of the procedures
is that it is difficult to establish systematic criteria for use
Another problem which has been reported are unpredicted
effects on behaviors which were not under explicit control
by reinforcement These changes are not necessarily
nega-tive, but since they were not under intentional stimulus
con-trol, they may create problems Finally, these procedures are
relatively new, and the history of psychology is replete with
procedures whose early promise has not been fulfilled
Although the major use of explicit control of behavior by
reinforcement contingencies has been in dealing with
abnor-mal behaviors, the principles are not limited to such
applica-tions An interesting example of an application in a different
context is the use of reinforcement techniques to reduce
lit-tering behavior in theatres and campgrounds
In addition to the techniques described above,
psycholo-gists and sociolopsycholo-gists have been concerned with the
effec-tiveness of communication in changing behavior Much
research has gone into such questions as the effect of the
status of a speaker on his persuasiveness, and the role of
var-ious social pressures in changing opinion In a sense, much
educational research can be looked upon as the study of a
special kind of behavior control where the concern is with
inducing behaviors which result in learning in an educational
setting Rothkopf has done some interesting experiments on
methods of inducing students to adopt appropriate behaviors
to facilitate learning, which he refers to as mathemagenic
behaviors
In evaluating the usefulness of such techniques in the
design of the social environment, it is important to take
cost-effectiveness criteria into consideration Judged by such
cri-teria, the more traditional psychotherapies do not come off
well They require highly trained manpower, in a relatively
large supply, and effectiveness is questionable, especially in
situations where the cooperation of the target population is
in doubt Modifications such as group therapy may dilute the
manpower requirements somewhat, but the other problems
remain The behavior therapies show up somewhat better in
such an analysis At least, it is possible to monitor behavior
change to determine whether they are effective, and once a
program has been established, it can often be carried out by
personnel with little formal training
In evaluating psychology as an information source for
social planning, the need for sound information from the
behavioral sciences cannot be overstressed, and every effort
should be made to obtain more of such information At the
same time, the many obvious limitations of our present data
suggest that they be used with due caution
In particular, with the increasing use of psychological
consultants in various aspects of environmental planning,
the bases for various expert opinions should be scrutinized
with great care The judgment of experts in the social
sci-ences, when it is not based on carefully controlled research,
can be very misleading The nature of the subject matter and the conditions of observation are such that it is very easy to find apparent support for a wide variety of hypotheses, many
of which may be proved incorrect with more careful obser-vation It is always desirable to ascertain the factual basis for any recommendation, and to obtain the views of as many professionals from different backgrounds as possible
FUTURE DEVELOPMENTS
The future cannot, of course, be predicted, but certain trends seem likely to continue First, techniques for controlling behavior derived from operant conditioning procedures appear likely to come into increasing use Environmental design will be likely to take into account more explicitly such facts in its design procedures Human engineering pro-cedures will also have an increasing impact on aspects of design for the environment Certain fundamental questions about human behavior in complex situations will become better understood, and will provide the informational basis for superior design of learning environments and other spe-cial purpose environments However, the 1984 or Brave New World fears seem unjustified at present The more extensive attempts to control human behavior are more notable for their weaknesses than their power Even predictive power is inversely associated with the behavioral complexity of the response Skinnerian techniques seem to offer the best road
at present to more powerful approaches However even here caution should be noted Most of the basic research on cur-rent contributions has been done on animals in very restricted environments It has also been done on animals in more or less severe states of need; pigeon experiments using a food reinforcement typically maintain the birds at some
percent-age of ad lib body weight, such as 85% Such animals are
very well motivated, and the powerful effects of positive reinforcements found in these studies should be interpreted
in this light It is possible that most humans remain in a simi-lar state of need with regard to the kinds of social reinforcers most likely to be manipulated in planning of larger environ-ments, but the point has yet to be established The limited environment is another factor which may lead to extensive modification of conditioning principles in larger situations, where a much wider choice of response alternative exist
However, the positive value for effective use of environmen-tal resources which can result from a better understanding of human needs and response to various environments is very great, and it is in this area that the greatest impact of psy-chology should be anticipated
REFERENCES
Alloway, Thomas M (1969) Effects of low temperature upon acquisition
and retention in the grain beetle ( Tenebrio molitor ), J Comparative and
Physiological Psychology, 69, 1
Alluisi, E.A and W.D Chiles (1967) Sustained performance, work–rest
scheduling, and diurnal rhythms in man, Acta Psychologica, 27, 436
Examination of Water and Waste Water, 17th Ed