Crowding Into the Behavioral Sink

Recent Applications

• Animal behavior after domestication undergoes a genetic change to be able to share a common space with humans
• Attributed to literature in pyschotherapy
• Counselors need to specialize in cross-cultured relations which becomes most relevant as cities grow

Criticisms

Results

• Study was done with rats and not humans
• Attempted to replicate the study in NYC in 1975 testing death rates, birth rates, aggressive tendencies (via court records), pyschopathology (via mental hospital admissions)
• However there were NO significant relationships between population density and these attributes

Significance

• Population density occurred on a moderate level when male rats matured they would fight for social status
• Different reactions occurred in different pens.
• 1 & 4 had only one exit route so the dominant male had less threats and more control over an average 8-12 female rats. Male visitors were extremely submissive and 50% of infant survival
• 2 & 3 held over 60 rats and resulted in the "behavioral sink" effect. Showcasing rats with extremely aggressive and submissive tendencies. Sexual deviant members known as "probers" who abandoned the rituals and became cannibalistic or "pansexuals" who held no limits to partners. All resulting in reproductive abnormalities where the mother rats lost desire to nest and protect their young and infant mortality raised to 80-96%.

Crowding Into the Behavioral Sink

• Overcrowded prisons showcase similar standards for testing.
• Inmate cells usually average 50ft and show signs significantly higher of mortality, homicide, suicide,and illness in crowded jails.
• Different studies have tested complex motor skills in crowded or open space and have shown increased blood pressure, heart rate, and less correct answers in crowded areas.

The Study Looking into Population Density and Social Pathology

By: John Calhoun

The Study that Started it All!

Who: John Calhoun

When: 1960's

What: Created a 4 quadrant pen and allowed for a double in population on their own to observe social behavior for 16 months.

Why: His inspiration came after his own previous study of creating a "rat paradise" free of any predators and disease resulted in effects he did not expect. Instead of the population expanding to over 5,000 rats it went only to 150 after 27 months.

What Is It Testing?

Problems With Density and Crowding Studies

Population Density: The number of individuals in a given space

V.S.

Crowding: The subjective experience that results from degrees of density

Methods

• Cant ethically put humans in crowded conditions for long periods of time
• Many outside factors can cause changes in results (I.E. Negative effects in Manhattan may not be caused by crowding but by poverty)

How to Study It

Density can be studied as well as crowding in areas where it is already taken place. For example: NYC, Time Square.

• Conducted 3 studies of Adult rats
• Lab Room 10-14sq ft & Divided into 4 pens
• ***Dividers were electric as to condition the rats to not climb between sections
• 12 Rats per pen, 48 total
• Allowed for population growth up to 80 then controlled for growth after that
• 16 month observation time from the ceiling