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

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

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

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

5. 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

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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

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

14. 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

15. 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

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

17. 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?

18. 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

19. 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)

20. 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

21. 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