Dorwin Cartwright

Some Neglected Variables in Contemporary Conceptions of Decision and Performance

Contemporary conceptions of the determinants of a tendency to perform a particular response are reviewed and found to be stimulus bound. They tend to attribute instigation to act in a certain way to the occurrence of a stimulus (external or internal) which serves to excite an otherwise latent associative mechanism like Habit or Expectancy in an organism implicitly assumed to be at rest. It is proposed that activity already in progress (initial activity) and the persistent effect of previously aroused but unsatisfied behavioral tendencies (inertial tendencies) be included in formal conceptions of the contemporaneous determinants of decision and performance. These suggestions follow from the premise that a living organism is constantly active and the assumption of inertia applied to behavioral tendencies.

A graph theoretic approach to the investigation of system‐environment relationships†

For any empirical structure consisting of a system S and its environment E, there is an associated digraph D whose points and arcs (directed lines) correspond to the elements and relationships of the structure. The arcs of D are thus of four types: (1) internal arcs, which join two points of S; (b) external arcs, which join two points of E; (c) out‐liaisons of S, which join a point of S to one of E; and (d) in‐liaisons of S, which join a point of E to one of S. The boundary of S is defined as the subgraph of D induced by the liaisons of S and corresponds to those elements and relationships of the structure directly involved in transactions between the system and its environment. The basic structural properties of boundaries are then identified, and it is shown how the points of S and E can be stratified according to their distances to (or from) the boundary of S. Next, several results are derived concerning system‐environment relationships in structures whose digraphs are symmetric, transitive, or signed....

The number of paths and cycles in a digraph.

An algorithm is presented for constructing from the adjacency matrix of a digraph the matrix of its simplen-sequences. In this matrix, thei, j entry,i ≠j, gives the number of paths of lengthn from a pointvi to a pointvj; the diagonal entryi, i gives the number of cycles of lengthn containingvi. The method is then generalized to networks—that is, digraphs in which some value is assigned to each line. With this generalized algorithm it is possible, for a variety of value systems, to calculate the values of the paths and cycles of lengthn in a network and to construct its value matrix of simplen-sequences. The procedures for obtaining the two algorithms make use of properties of a line digraph—that is, a derived digraph whose points and lines represent the lines and adjacency of lines of the given digraph.

Social Psychology in the United States During the Second World War

This article, together with a number of others, was prepared at the request of the American Council of Learned Societies, partly for the information of scholars in other countries. Distribution of the articles outside the United States will be accomplished by a special distribution of reprints as well as through the complete issues of the journals in which they appear. The bulk of the materialpresented in this article was collected by a committee of the Society for the Psychological Study of Social Issues on the Evaluation of Social Psychology in the War. Special credit should be given to Mr. David Jenkins who assisted in the compilation of the material presented here.

A note on a matrix criterion for unique colorability of a signed graph

A signed graph,S, is colorable if its point set can be partitioned into subsets such that all positive lines join points of the same subset and all negative lines join points of different subsets.S is uniquely colorable if there is only one such partition. Developed in this note is a new matrix, called thetype matrix ofS, which provides a classification of the way pairs of points are joined inS. Such a classification yields a criterion for colorability and unique colorability.