Crowding Into The Behavioral Sink Calhoun, J. B. (1962). Population Density and Social Pathology. Scientific American, 206, 139-148. Presented by Edward Londono

Introduction Population density- the number of individuals in a given amount of space Crowding- the subjective population experience created by density

Theoretical Propositions Calhoun wanted to study the effects of high population density on social behavior. Does the stress of social interaction alter behavior?

Method Series of 3 studies 32-56 rats to start placed in a laboratory room 10ftx14ft wide glass ceiling for observation

Method (cont.) Room divided into 4 sections by electrified partitions sections 1 and 4 were end sections 3 led to 2 and 4 2 led to 1 and 3 you could not cross from 1 to 4

Method (cont.) Pens contained feeders, waterers, and enclosures for nests plenty of food, water, materials for building nests

Method (cont.) Normally each section could contain 12 adults, which would allow for 48 rats Calhoun allowed rats to multiply to nearly double-80 he observed the rats under these conditions for 16 months

Results Males battle for dominance in all 4 pens in pens 1 and 4, when one male won dominance he was able to defend his pen by guarding the only entrance into the pen therefore, in pens 1 and 4 there was 1 male rat and a harem of 8-12 female rats behavior in these pens was normal

Results (cont.) This left about 60 or so rats crowded into the other 2 pens this is where Calhoun termed the phenomenon which he called the “behavioral sink” there were 4 extreme pathological behaviors he observed: aggression, submissiveness, sexual deviants, and reproductive abnormalities

Aggression Rather than 1 on 1 fights, male rats were observed in brawls for dominant positions in the social hierarchy going berserk, attacking females and juveniles biting other rats on the tail

Submissiveness This group consisted of the most healthy looking rats in the pens because they avoided battles for dominance they were observed moving through the pens in a sort of hypnotic trance they were completely uninterested in sexual activity

Sexual Deviants (Probers) Hypersexual; always on the prowl for receptive females not interested in fighting for status some even became cannibalistic refused to participate in natural rituals of mating

Sexual Deviants (Pansexuals) Attempted to mate with any rat indiscriminately males, females, and juveniles that were not in heat did not fight for dominance

Reproductive Abnormalities Females lost inclination to build adequate nests mothers lost maternal ability to transport young from one place to another they would forget some of the litter or sometimes abandon them females who were in heat were chased by large groups of males until they were unable to escape-these females experienced high rates of complications during pregnancy and delivery

Significant Findings One environment where the behavioral sink may occur is in extremely overcrowded prisons a study done by The National Institute of Justice found significantly higher rates of mortality, homicide, suicide, illness, and disciplinary problems

The Development of Mood-Inhibiting Effects of Crowding During Adolescence Prerost, Frank J. Journal of Psychology, 1982, 110, 187-202.

Theoretical Proposition Previous studies have found that human crowding causes unpleasant mood states which in turn produces stress Does crowding cause unpleasant mood states or does it inhibit pleasant mood states?

Method 3 groups of 24 males and 24 females groups ages were 13, 16, and 19 each group was divided into groups of 6 of the 4 groups of 6, 2 groups were placed in crowded settings and the others in a non-crowded environment

Method (cont.) Half of the crowded/non-crowded groups were presented with non humor reading the other half with 36 humorous jokes of a neutral, aggressive, and sexual nature (12 of each)

Method (cont.) Aferwards, mood was assessed with the Nowlis-Green Mood Adjective Checklist 5 mood states were presented: aggression, euphoria, anxiety, social affection, and negative egotism

Results Findings suggest that crowding, rather than being an unpleasant stressful condition, suppresses positive mood and thereby enhances the possibility of negative-mood development males appeared to be influenced by the crowding more easily than females the effectiveness of the positive mood-producing stimuli (humorous jokes) was inhibited by crowding