The behaviour of the rats under crowded conditions deteriorated so much that Calhoun described the effect as the behavioural sink. Despite a quarter of an acre of space with no predators the population levelled off at one hundred and fifty while such a space might have been predicted to accommodate several thousand. The reason for this was the very high level of infant mortality caused by the aggressive attacks from adult males on pregnant females and often cannibalism in eating the newborn.
The females lost their maternal instinct and often abandoned their young. Aggression was rampant, and aberrant sexual behaviour was common. Some animals became hyperactive while others became withdrawn and appeared depressed. In general there appeared to be a vast increase in psychopathology. The experiment was a laboratory study so there was high degree of control but low ecological validity. There have been many criticisms of Calhoun’s research, the ethics involved with the distress caused to the animals.
Critics have also suggested that the environment was not natural even for rats or mice and ultimately that the findings from animal studies cannot be generalised to humans. The research was done in the sixties if could be said that it was very much of its time, people were worried about over population. The experiment illustrated the political views at the time. Calhoun’s research could be said to be anthropomoric, but the results highly suggested that animals experience severe, negative physiological and behavioural reactions to high density.
There are many ways in which the feeling of crowding can be reduced. Architects building new structures should take many things into consideration so that crowding is less of a problem. Savinar (1975) found that greater ceiling height is associated with less crowding for males. Rotton, (1972) found that rooms with well defined corners elicit less crowding than rooms with curved walls. Desor, (1972) found that rectangular rooms seem to elicit less crowding than square rooms, and rooms that contain visual escapes such as windows and doors are rated as less crowded than similar areas without such escapes.
The height of a building can also effect the feeling of crowding, Mc Carthy and Saegert, (1979) found that high rise buildings perceive a greater feel of over crowding than low rise buildings. There are many ways that you can change an existent structure to reduce the feeling of crowding. Dabbs, Fuller and Carr, (1973) found that placing activities, objects in the centre of the room rather than putting them in a corner or along a wall elicited less crowding.
Partitions giving a privacy corner in prisons elicited less crowding, inmates having the cubicles in their dormitories had much more positive reactions to their environment and had lower rates of non-contiguous illnesses (McGuire and Gaes, 1982). The presence of visual distractions for example pictures on walls and advertisements on transportation vehicles can also lead to more perceived space (Baum and Davis, 1976; Worchel and Teddlie, 1976). The arrangements of seating can also elicit less crowding; socio- fugal seating arrangements are associated with less crowding than socio- petal seating.