Section 7: What Makes Us Human?
Q1:
Section 7: What Makes Us Human?
Discuss the 3 major changes in human evolution, bipedalism, brain expansion, and culture. Consider the specific anatomical changes of bipedalism and brain structure and discuss specific aspects of culture itself. What makes us human and how natural selection was involved in our ultimate design. Remember to use terms from text and lecture.
Video source: http://www.ted.com/talks/susan_blackmore_on_memes_and_temes.html
EVOLUTION OF THE HUMAN BRAIN AND HUMAN BEHAVIOR
Renee Garcia
Brain size or encephalization
Weighing 2.7 lbs. his brain was slightly below average… so size really doesn’t matter
Hominid Brain Evolution
- Encephalization or the measure of brain size relative to body size
Human brain after years of TV and web browsing
Brain moves forward
- Forward movement of the frontal bone
- Expansion out of the parietals and occipital
Distribution of brain volume in fossil hominids
Brain Reorganization
- Key areas of change:
- Olfactory bulbs
- Frontal lobes
- Primary Visual Regions
Olfactory bulbs
- Large prefrontal region
- Forming goals and making plans
Frontal lobes
Primary Visual Cortex: sensory information from various sources is processed and synthesized.
Four Approaches
- Paleontological
- Biocultural
- Evolutionary Psychology
- Human Evolutionary Ecology
Paleontological
- Reconstructions of behavior based on the anatomy of extinct hominids and on the archaeological cultural remains associated with the fossils.
Neandertal child’s brain from CT scan volume reconstruction
Biocultural
- This is exemplified by language. This ability to communicate effectively certainly had direct influence on our biology as in the case of slash-and-burn agriculture that had an indirect effect on sickle cell development.
Evolutionary Psychology
- A new discipline that adheres to 3 main principles:
- Human and animal behavior is not produced by minds that are general-purpose devices, but instead the mind is composed of cognitive modules with underlying neuroanatomical basis that express specific behaviors in specific situations.
Cognitive modules are complex design features of organisms. As natural selection is the only way to evolve complex design features.
The belief that our evolved behavior may reflect or should be interpreted in terms of this hypothetical environment of evolutionary adaptedness.
These are viewed as adaptations
Human Evolutionary Ecology
- This study focuses on psychological experiments and surveys of people in developed countries
- Focuses on the ecological factors that influence reproductive success in the remaining hunter-gatherer populations
- Topics of interest include the relationship between status and reproductive success, demographic effects of tribal warfare and aggression and the social impact of hunting and food-sharing.
Sweaty T-shirt
- Pheromones and immune systems
Witches in Papua New Guinea
Sexual Selection
- Females tend to value resource-providing ability in their partners, whereas men tend to value youth and appearance in their potential partners.
Risk-Taking Behavior
- High death rates in young adult males
- More likely to take risks
- May be due to significant sex difference in human behavior based on evolution over time
- For example, aggressive behavior in males may be the result of competition for females
- May also be viewed by females as manifestation of “good genes”
