Outline 9/24/98

Evolution and human behavior

Evolution and Mate Selection

Men and Beauty

Women and Status

Evolution and Determinism

The Structure of the Nervous System

Central & Peripheral

Three Major Divisions of the Brain

Hindbrain, Midbrain, Forebrain

 

 

 

But what is beauty?

Is beauty defined by evolution or by culture?

 

Waist-to-hip Ratio vs. Body Weight

Low waist-to-hip ratio (WHR) is correlated with early onset of puberty, lower risks of diabetes, lower risk of ovarian and breast cancer, lower risk of heart disease and mortality. (In the popular press this is often called the "pear shape" vs. the "apple shape").

In comparison to WHR, body weight is a poor predictor of reproductive status and health.

 

 

Singh (1993) did two studies.

In the first, Singh examined the ideal weight and WHR of Miss America winners and Playboy centerfolds.

In the second, Singh asked men to rate attractiveness of various women and systematically varied their ideal weight and WHRs.

 

 

Singh's Results for Miss America and Playboy centerfolds

 

 

 

Singh's Stimuli for Second Study

 

 

 

Singh's Results for Study 2

Singh found that WHR had a greater impact on preferences than did ideal body weight. Subjects consistently rated low WHR models more attractive, independent of body weight.

 

 

 

 

So...

Should we conclude that men's focus on physical beauty (especially WHR) and women's focus on status are natural, and therefore, good things?

No, to do so would be to commit the naturalistic fallacy--the assumption that because something exists naturally, it is good

 

 

Consider A Patient with Parkinson's Disease

 

 

 

Should we conclude that men and women's mate preferences are determined by their evolutionary heritage--that they are hostage to the whims of natural selection?

 

No, to do so is to commit the deterministic fallacy

 

The Deterministic Fallacy

The conclusion that genes (or heredity) determine behavior in a rigid way that is essentially unaffected by the environment.

 

 

 

Should we conclude that because a behavior was "adaptive" at some point in our evolutionary heritage that it is still adaptive?

No, consider the physiological toll associated with everyday anger and stress

 

 

 

 

Biological Approaches to Behavior: Proximal Causes

 

 

 

Why Study Biology in a Psychology Class?

 

 

 

Proximal Causes and the macro structure of the nervous system: The Central Nervous System and Peripheral Nervous System

 

 

 

Peripheral Nervous System

The somatic system (soma means body)--connects central nervous system to voluntary muscles.

The autonomic system--connects the CNS to nonvoluntary muscles, glands, and organs.

 

 

 

Within the Autonomic Nervous system can distinguish between the sympathetic and parasympathetic systems.

 

 

 

 
The Brain

 

 

 

The Hindbrain

 

 

 

The Midbrain

 

 

 

The Forebrain