Robert J. Havighurst

Examples of Robert J. Havighurst in the following topics:

• Activity Theory

  • The theory was developed by gerontologist, or, scholar of aging, Robert J.
  • Havighurst in 1961, and was originally conceived as a response to the recently published disengagement theory of aging.
  • Havighurst's activity theory is at deliberate odds with what some perceive as the pessimism of disengagement theory.

• The "adjacency" matrix

  • If Bob and Carol are "friends" they share a "bonded tie" and the entry in the Xi,j cell will be the same as the entry in the Xj,i cell.
  • In this case, the element showing Bob's relationship to Carol would be scored "1," while the element showing Carol's relation to Bob would be scored "0. " That is, in an "asymmetric" matrix, Xi,j is not necessarily equal to Xj,i.
  • That is, the element i,j does not necessarily equal the element j,i.
  • If the ties that we were representing in our matrix were "bonded-ties" (for example, ties representing the relation "is a business partner of" or "co-occurrence or co-presence," (e.g. where ties represent a relation like: "serves on the same board of directors as") the matrix would necessarily be symmetric; that is element i,j would be equal to element j,i.
  • In representing social network data as matrices, the question always arises: what do I do with the elements of the matrix where i = j?

• Summary

  • An adjacency matrix is a square actor-by-actor (i=j) matrix where the presence of pair wise ties are recorded as elements.

• What is a matrix?

  • A "3 by 6" matrix has three rows and six columns; an "I by j" matrix has I rows and j columns.

• Bibliography

  • Barnes, J.A. 1983.
  • Blau, Peter and Robert K.
  • Brym, Robert J. 1988.
  • Davis, J. 1963.
  • Leik, Robert K. and B.F.

• Doing mathematical operations on matrices

  • This simply means to exchange the rows and columns so that i becomes j, and vice versa.
  • One simply adds together or subtracts each corresponding i,j element of the two (or more) matrices.
  • Of course, the matrices that this is being done to have to have the same numbers of I and j elements (this is called "conformable" to addition and subtraction) - and, the values of i and j have to be in the same order in each matrix.

• Making new kinds of graphs from existing graphs

  • In our current example, the Product choice (that is, multiply the score of actor i times the score of actor j, and enter the result) would yield a score of "1" if two actors shared either support or opposition, "-1" if they took opposed stands on the issue, or "0" if either did not take a position.