Paraconsistent algebras

The prepositional calculiC _n , 1 n introduced by N.C.A. da Costa constitute special kinds of paraconsistent logics. A question which remained open for some time concerned whether it was possible to obtain a Lindenbaum's algebra forC _n . C. Mortensen settled the problem, proving that no equivalence relation forC _n . determines a non-trivial quotient algebra.The concept of da Costa algebra, which reflects most of the logical properties ofC _n , as well as the concept of paraconsistent closure system, are introduced in this paper.We show that every da Costa algebra is isomorphic with a paraconsistent algebra of sets, and that the closure system of all filters of a da Costa algebra is paraconsistent.     

Absolute motion parallax and the specific distance tendency

In the absence of definitive cues’to distance, the perceived distance of an object will be in error in the direction of the object appearing at a distance of about 2 m from O. This tendency to perceive an object at a relatively near distance is termed the specific distance tendency (Gogel. 1969). Also, it has been found that an error in perceiving the distance of an object will result in an apparent movement of the object when the head is moved (Hay & Sawyer. 1969; Wallach, Yablick. & Smith. 1972). From these two results, it was expected that the direction of trie apparent movement of a stationary point of light resulting from head movement would vary predictably as a function of the physical distance of the point of light from O. This expectation was confirmed in an experiment in which both the perceived motion and perceived distance of the point of light were measured. The consequences of the study for the role of motion parallax in the perception of distance and for the reafference principle in the perception of object motion with head motion are discussed     

Attractiveness of Occupations to High School Students

Information was obtained by questionnaire from a sample of approximately 3,100 Washington high school juniors and seniors concerning career aspirations and whether they would like or dislike each of 61 selected occupations. Analysis of the responses shows (1) that a wide range of occupations, including many nonprofessional occupations, would be attractive even though 67 per cent of the boys and 59 per cent of the girls aspired to professions, (2) that students tend to reject occupations traditionally followed primarily by the opposite sex as well as a number of other occupations, and (3) that the prestige ranking of a specific occupation is not a very good predictor of occupational likes and dislikes of students. The implications of these findings are discussed.     

The adjacency principle and induced movement

The apparent movement of a stationary point of light was investigated as a function of the apparent distance of the point of light with respect to the inducing frame of frames. When two frames were presented simultaneously, they were at different distances and physically moved at opposite phase in frontoparallel planes. When one frame was presented alone, it was positioned at different times at each of the two distances. The point of light was presented stereoscopically at the distance of either the near or far frame or midway in depth between these distances. With the single frame, it was found that the magnitude of the induced movement decreassed as the point of light was increasingly far in front of a frame but decreased less or remained approximately constant for distances be hind a frame. With the two frames presented simultaneously, it was found that as the depth between a particular frame and the point of light decreased, the contribution of that frame to the induced movement increased. The results illustrate the interaction of perceptions, in this case perceived depth and perceived motion, and are consistent with the adjacency principle.     

Computer production of punched paper tapes for controlling experiments

Controlling experiments with paper-tape readers often requires the production of complex paper tapes. A program was written to allow automatic production and checking of complex punched paper tapes using a small computer. The user first defines the punches or punch sets to be used. He then specifies, for each successive block of tape to be punched, the number of punch sets of each type to occur and whether those punch sets should be copied in order or automatically randomized. The specified tape is then produced using a two-pass procedure, after which the tape may be automatically checked for punching errors if desired. The program has facilities for retention or modification of user commands from previous runs, simplifying the production of a large number of tapes with similar characteristics.     

Lateral word recognition: Effects of unilateral and bilateral presentation, asynchrony of bilateral presentation, and forced order of report

This experiment enquired: (1) whether right visual field (RVF) recognition superiority was greater in bilateral than in unilateral word presentation; (2) whether left field-favouring attentional or recall sets could be induced by presenting left visual field (LVF) words 20 msec prior to RVF words or by instructions to report LVF words prior to RVF words. Results showed: (1) all conditions studied yielded significant RVF superiority; (2) RVF superiority magnitude was significantly greater in bilateral than in unilateral presentation, suggesting the tenability of hypotheses that different mechanisms operate in these conditions; (3) neither earlier delivery nor earlier report of LVF words altered the pattern of RVF superiority in bilateral presentation, the later result demonstrating that differential receptive organization rather than differential recall of the two stimuli is responsible for RVF superiority in bilateral presentation.     

Self-esteem as a moderator of performance-satisfaction relationships

Korman's (Journal of Applied Psychology, 1968, 52, 484–490) prediction that performance and satisfaction should be positively related for high self-esteem individuals and unrelated for low self-esteem individuals was tested with samples of scientists, engineers, homemakers, firefighters, and clerical workers. Although there was a slight tendency for this prediction to be supported with the male scientist, engineer, and firefighter samples, Korman's theory was unsupported in the homemaker and clerical worker samples. Since the correlations found for low and high self-esteem persons significantly differed in only one of eight comparisons, self-esteem did not appear to be a reliable moderator of the performance-satisfaction relationship. Problems with previous studies purporting to test Korman's prediction are discussed, and the possibility of a confound between self-esteem and sex role and/or status is introduced.     

Reading rate and retention as a function of the number of propositions in the base structure of sentences

English texts were constructed from propositional bases. One set of 16-word sentences was obtained from semantic bases containing from 4 to 9 propositions. For another set of sentences and paragraphs, number of words and number of propositions covaried. Subjects read the texts at their own rate and recalled them immediately. For the 16-word sentences, subjects needed 1.5 sec additional reading time to process each proposition. For longer texts, this value increased. In another experimental condition reading time was controlled by the experimenter. The analysis of both the text and the recall protocols in terms of number of propositions lent support to the notion that propositions are a basic unit of memory for text. However, evidence was also obtained that while the total number of propositions upon which a text was based proved to be an effective psychological variable, all propositions were not equally difficult to remember: superordinate propositions were recalled better than propositions which were stucturally subordinate.     

Behavior therapy for obesity: Booster sessions and long-term maintenance of weight loss

Following 8 weekly sessions of group behavioral self-control treatment, 75 obese women were assigned to one of five different maintenance conditions: (a) structured behavioral booster sessions held every two weeks; (b) structured behavioral booster sessions held every month; (c) unstructured nonspecific booster sessions held every two weeks; (d) unstructured nonspecific booster sessions held every month; and (e) a control group that received no booster sessions. Follow-ups were conducted at 3, 6, 9 and 12 month intervals. The study was completed in two replications. Results failed to show a significant effect of either booster session content or frequency. All groups continued to lose weight during the first three months of follow-up. Thereafter subjects in Replication 1 showed significant increases in weight over the next 9 months, whereas subjects in Replication 2 maintained their treatment-produced weight loss. The data do not support the view that booster sessions facilitate maintenance.