Learning Chapter 1

Chapter 1 Learning to Change

Learning 

Learning is a change in the behavior of an organism due to experience. 

Behavior is anything that an organism does that can be measured.

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Experience: exposure to events that affect (or are capable of affecting) behavior.  

We call these events stimuli. Stimuli are physical events that can originate outside the body or inside the body.

Change: Environmental and  Behavioral Organisms live in specific environments and must adapt to those environments to thrive. 

Problem: Environments change. 

Slow Changes (beyond the life of individual organisms): 

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Continental drift, ice ages, global warming, desertification, deforestation, depopulation

Changes during a lifetime 

Natural disasters, weather, predators, illness

Change 

Species Change: Evolution by Natural Selection 

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Gradual change in the distribution of physical and behavioral characteristics in populations of organisms.

Individual Change: Learning

Darwin’s Theory of Natural Darwin contrasted natural Selection with artificial selection. 

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Animal breeders select physical and psychological characteristics through controlled breeding of animals. But suppose: Unfriendly and aggressive fox’s (for whatever reason) were sterile or died before reproducing. Only docile and friendly fox’s would reproduce. Those traits would grow in frequency in the fox population. The consequence would be the same as if the foxes were

Belyaev and Trut (1999)

Natural Selection Natural selection is an evolutionary process through which adaptive traits are passed on to ongoing generations because these traits help animals survive and reproduce. In natural selection, nature (the environment) determines what traits get transmitted. If a trait leads to death before reproduction or interferes with reproduction (maladaptive traits), it gets weeded out of populations over time. If a trait increases survival and reproduction (adaptive fitness), the trait is transmitted to offspring. By this process, traits increase or decrease in frequency in populations.

Natural Selection    

Natural selection is NOT a theory of The origins of nature, or being-as-such The origins of life It is a theory of changes in characteristics of a species, and potentially of the origins of new species (arising from existing species).

Blind Variation and Selective Retention. 

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Natural selection is an example of a broader class of processes that lead adaptive change. Donald Campbell: BVSR processes In such a process there are three essentials:   

(a) Mechanisms for introducing variation; (b) Consistent selection processes; and (c) Mechanisms for retaining and/or propagating the selected variations.

Try Things, Keep What Works   

Try Things (Variation), Keep (Retention) What Works (Selection)

Examples of BVSR processes Process

Variation

Selected by

Language Learning Creative Arts

Infant Babbling

Parents/Commu Brain/Memory nity Artistic Brain/Memory/ Judgment Archives

Production of ideas

Immune System Random Antibodies Evolution Recombination/ Mutations

Antigens (Invaders) Nature/ Environment

Retention

Cloning Genetic Code of Offspring

What Darwin didn’t know…  

Genes: produce proteins Proteins: Produce physical structure of organisms 

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Including brains and nervous systems—hence the relevance to psychology.

Sexual Reproduction: Produces variation in genes (and hence in physical structures and psychologies) through recombination. 

Variation in genes can also occur through mutations

Peppered Moths 

Frequencies of moth colors “selected” by industrial soot.

Easily seen moths picked off by predators

Classes of Behavior FROM:

TO: Species-Specific Mechanisms

Cross-Species Mechanisms

Highly Heritable

Low Heritability

Stereotypical Patterns, Relatively Unmodifiable Simple Responses

Flexible Patterns, Relatively Modifiable Potentially Complex Behaviors

Reflexes

Modal Action General Patterns Behavior Traits

Learned Behaviors

Reflexes 

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A reflex is a relationship between a specific event and a simple response to that event. Often protect organisms from injury. Example: Withdrawal Reflex Also: *eyeblinks *sneezing *vomiting

Human Infant Reflexes     

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Rooting (touch cheek turn) Sucking (when nipple placed in mouth) Food Salivation Food & Saliva  Swallowing Swallowing  peristalsis (motion in esophagus that carries food to stomach) All very useful, promotes survival, and does not require learning.

If only. . . 

Calculus reflex

Phenomena Assoc/w Reflexes 

Sensitization: Eliciting a reflex often leads to an increase in the probability or intensity of a response to the same (or closely related) stimuli. 

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Loud noises can elicit the startle response (jump). We are more likely to startle again immediately afterword (no other, even weaker) noises. Scary movies?

Phenomena Assoc/w Reflexes 

Habituation: Repeatedly evoking a reflexive response will often weaken or decrease the probability of a response to the same stimulus.

Sokolov: the orienting response (OR) in dogs 

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New Stimulus looking toward stim., ears lift, wave of neural and physiological activity (HR, breathing, etc) With time, OR fades; appears that organism no longer aware of stimulus.

Habituation

Modal Action Patterns 

A series of interrelated actions found in most members of a species, usually triggered by specific stimuli (called “releasers,” or “releasing stimuli”) 

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Usually involves the whole organism (unlike reflexes, which often involve specific muscles or glands). Are more complex than reflexes, extended over a longer period of time. They are stereotypical, but more variable than reflexes. They often appear to be a long chain of reflexes following one another.

Example MAPs 

Examples: 

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Spider web spinning Cat defensive posture (hiss, arch back, fur on end, tail swishing —makes cat seem larger, more threatening) Playing possum Courtship & mating dances

General Behavior Traits 

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Broad behavioral tendencies that occur across many situations (no inborn, specific releasers). Often highly heritable (EAS; R. Plomin):  

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Activity Levels Sociability (tendency to approach and interact with others—highly variable in young children) Emotionality (e.g., fearfulness)

Basically, temperament and personality by another name.

Learning 

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Reflexes, MAPS, and General Traits are often adaptive. They have likely evolved over centuries and perhaps help organisms coping with their average expectable environments. But there are still day-to-day surprises, changes within an individual’s lifetime. The capacity for flexible change in a lifetime is probably an evolved capacity as well.