CROWDING

Rationale for Psychological Study of Crowding

(1) Public concern over crowding and negative connotations of ‘crowding’ — crowded cities, prisons, classrooms, dorms, busses, etc. all with alleged

adverse behavioral and physiological consequences. Therefore we should study it. But people do not feel crowded just because of the presence of others. Feel crowded when others constrain or interfere with one’s behavior (control model), prevent one from obtaining resources (ecological model), or when others threaten with overload — too many in too small a place (spatial density) or are faced with regulating one’s interaction with a number of others (social density).

(2) Population density. US population density is approximately 77 people per square mile. The range is from 1 person/sq.mile in Alaska to around 5 in Wyoming through around 77 in Texas to a little over 1,000 in New Jersey. The US, in general, does not seem crowded., although some cities are crowded. Some figures for other countries are: Mexico — 128, China 334, England 615, India 737, Japan 862, Netherlands 960, and Bangladesh 2,150.

(3) Animal Research . Research with animals has been taken to indicate that animal populations will grow and, even in the presence of sufficient resources (food and water) and the absence of predators and disease, crash down to some low point with the animals showing signs of stress. The results of ‘free growth’ studies are variable — even with the same species. Some grow and crash, others grow and stabilize, but the population achieved can be very different for different trials with the same species. However, the main animal study cited to show the adverse effects of population density is Calhoun’s study with rats in which the rats were raised in interconnected pens and the population held at 40 males and 40 females. Unlimited food and water was provided in the middle two pens. Life in the outside two pens was ‘normal’. Two or so males congregated with a harem of eight or so females and bred and survived. Each of the interior pens had about 18 males and 12 females and Calhoun used the term ‘behavioral sink’ to describe their behavior which included homosexuality, the eating of the rat pups, premature termination of pregnancies, etc. The rats were not able to engage in their normal mating behavior (a male and a harem of females), were spatially dense, and had to suffer the territorial invasions of the rats from the outer pens. If one prevents normal patterns of behavior, one may get abnormal behavior.

Begun by Paul Ehrlich (population biologist) and John Friedman (social psychologist). Manipulated both spatial density (space per person) and social density (number of people), (although number of people was ‘low’ (max. of 9) to avoid confounds such as increased room temperatures). Also able to look at effect of pure social density — increase in number of people with space per person the same. Had high schools males and temporary employment females do tasks for several hours a day for several days. Found no effects of manipulations. Why not? (a) Limited duration? But women did study for four hours a day for five days. (b) Have explanation for high density (experimenter wants it) so not aroused by personal space invasion. (3) Not a situation where others interfere with one’s goals or compete with one for resources or pose a threat, so no effects of others.

Some lab studies find effects, particularly with social density and when saliency of others is enhanced (subjects evaluate or criticize one another) and when tasks are complex. One explanation is Yerkes-Dodson Law: Social density leads to arousal which leads to fall off in performance. Alternatively, having others in an environment can be distracting which can reduce performance. Have found evidence that there is a ‘cost’ of coping with others. Study had subjects work in socially and spatially dense setting. Some subjects had no perceived control, others had control (want you to work there, but if you would really prefer not to, you can move over here by yourself). Having control did not affect performance in the group setting, but did result in more tolerance of frustration in the impossible figures task performed alone as an aftereffect task. (Same pattern of results as Glass and Singer’s aftereffects of noise study.)

Friedman then looked at social dependent variables, rather than cognitive ones. Found with low spatial density a tendency for males to be competitive and females cooperative and the difference between males and females increased with high spatial density. Same pattern of results for liking other people in the group. Females tended to like the others more than males did with low spatial density and the difference for females and males was greater with high spatial density. Denisity-intensity theory of crowding. Crowding (esp. spatial density with its arousal caused by personal space invasions) leads to an intensification of one’s ‘normal’ reaction to a setting. More laughter and greater rating of humorousness to a (funny) film viewed by groups of 15 when they were spatially dense rather than spread out.

Naturalistic Studies of Crowding

As population of a prison increases, find increase in death rate (stress from high density), increase in discipline infractions (three times greater than population increase), suicides, etc. Attributed to social density more than spatial density because prisons with larger populations more affected than smaller ones, even when had more space per prisoner. Also, prisoners who live in wards (and therefore have to interact with more people) affected more than those in double cells or single cells. Social density (and, to some extent spatial density) lead to demand for social interaction which can interfere with goals, produce uncertainty and directly (and mediated by these other factors) impose a cognitive load. (See prison crowding diagram)

Three vs. two students in two-person room causes lower ratings of satisfaction with roommate(s) and perceived cooperativeness of roommate(s). May be a resource — goal interference effect caused by having to cope with two others in a confining setting. May also be a dyad and an isolate effect.

Within a city find correlation between density of census tracts and indices of pathology (crime, mental hosp. admissions, etc.) But the correlations disappear once control for socio-economic-status (SES).

If look at internal density (#people/room in apartments) find effects if crowded (ratio of one or greater) — poorer mental and physical health and poorer relationships in the home. Holds even when control for SES. As people/room increase less able to achieve privacy and less able to regulate social interaction with the others.