Answer to Question 1
Answer: Both the investment and social exchange models address how relationship partners perceive the costs, rewards, comparison level (rewards-costs), and comparison level for alternatives. Rusbult's model includes an additional variable; she addresses partners' perceptions of how much they have invested in the relationship (both tangible and intangible) that would be lost were the relationship to dissolve. Rusbult has found that the greater the investment people have in a relationship, the less likely they are to leave it, even if costs outweigh rewards and other alternatives look promising.
Answer to Question 2
Answer: Mary Ainsworth and her colleagues (1978) have found that infants with a secure attachment style have caregivers who are responsive and show positive emotions; infants with an avoidant attachment style have caregivers who are aloof and distant and discourage intimacy; infants with an anxious/ambivalent attachment style have caregivers who are inconsistent and overbearing in their affections. In adulthood, the attachment styles experienced in early childhood predict how people typically approach romantic relationships. For example, secure attachment styles are associated with trusting others, easily establishing intimacy, and having satisfying relationships; avoidant attachment styles are associated with discomfort with intimacy, difficulty trusting others, and less satisfactory relationships; anxious/ambivalent attachment styles are associated with obsessiveness and preoccupation with relationships, and fears that partners do not reciprocate a need for intimacy.
Watson and Crick and their model of the DNA double helix
A model for the operation of voltage-gated sodium channels.
Strand displacement model for mitochondrial DNA replication
A model for RecA-mediated strand exchange
Global Climate Model
The first generation of model organisms in genetic analysis