Proactive interference and spontaneous alternation in rats

Two pairs of trials were given to naive rats in a T-maze. The first trial of a pair was forced to one arm, the second was free, and the delay between trials was 25 min. or 10 hr. Rats left in the maze for 15 sec. following the forced choice showed increased alternation on the second pair of trials at the 25-min. delay as compared with the 10-hr. delay. This was interpreted as due to a decline in alternation with delay on this pair of trials, together with an overall increase in alternation between the first and second pairs, and is consistent with the proactive interference theory of forgetting. Rats left in for 2 min. showed a decline in alternation with delay on the first pair of trials, but not on the second; this is inconsistent with the proactive interference theory.     

Synchronization and coupling of phases in periodic processes of conditioning

Locomotor avoidance conditioning and locomotor food conditioning in male albino rats demonstrated that locking of temporary connections is accomplished by coupling of phases of different synchronized periodic neural processes. Phase coupling was verified by the formation of parallel periodic courses of reaction times and motor reaction times in the process of elaboration of conditional avoidance reflexes, and by the curve of the corresponding correlation coefficients, which were calculated from the reaction times and motor reaction times in food conditioning measured every day during the period of stabilization. The authors hold the view that a locking mechanism based on the synchronization of periodic processes in conditioning is most compatible with efficient formation of conditional reflexes and can promote adaptation. Furthermore, it is assumed that information storage, too, occurs periodically, according to the principle of rotary storage.     

The organization of motivated and conditional reflex processes

Recent observations on the plasticity of brain and behavior relationships indicate that the temporary connections between environmental and neuroanatomical substrates have tremendous specificity but at the same time are very plastic. Establishment of a conditional reflex by stimulation of the hippocampal pyramidal layer and/or the mesencephalic reticular formation did not interfere with the differential stimulation of very near points in the same structures. These correlations between brain and behavior confirmed the earlier belief that the development of temporary connections between environment and brain is an elementary process of the central nervous system. Complex behavioral functions are organized through both neuronal and humoral afferentation. Data accumulated recently indicate that the descending forebrain influence is inhibitory in the brain stem and diencephalon and controls the sensory input in a somatomotor-specific and situation-specific manner. Humoral factors affecting thresholds can change the dynamic equilibrium existing between ascending excitatory and descending inhibitory systems; these alterations always follow the rule of situation and somatomotor specificity.     

College Major Choice and Personal Adjustment

This investigation focused on the differences in reported personal adjustment problems between freshmen students who made a congruent college major choice and students who made an incongruent choice. Personal adjustment was defined operationally with the Mooney Problem Checklist. Congruent and incongruent college major choice groups were defined operationally using the Vocational Preference Inventory. In the analysis of variance of the adjustment scores, the interaction term involving congruence of major choice and sex and the test for the main effect of sex were not significant. The test for the main effect of congruence was found to be significant. Subjects who had made a congruent college major choice reported fewer personal adjustment problems when compared to subjects in the incongruent group.     

Integrated circuit random foreperiod device and digital interval timer1

A digital integrated circuit computer that produces random (as opposed to pseudorandom) foreperiods is described. Also contained in the device is a precision digital interval timer.     

Direct quantitative judgments of sums and a two-stage model for psychophysical judgments

Judged magnitudes of differences between stimuli have previously been shown to support a two-stage interpretation of magnitude estimation, in which input transformations and output transformations are each describable as power functions. In an effort to provide support for the model independent of the difference estimation procedure. the present investigation employed two additional judgment tasks. We obtained magnitude judgments and category judgments of the combined magnitudes (sums) of paired weights from two groups of Ss. Values of the inferred input exponent k calculated from the two sets of data were very similar and were also remarkably similar to the exponent previously calculated from magnitude estimations of differences between weights. The output exponent calculated from magnitude judgments of sums described a concave upward function; however. the similar function describing category judgments was essentially linear. These results show that the inferred input exponent is not the result of the difference estimation task, and in addition provides support for the contention that the interval scale may be a less biased sensory measure than the magnitude scale. The introduction of an additive constant to the model improved its fit to the data but the rule by which it was introduced made very little difference.     

The effects of area and perimeter on detection rates

The detection of luminance increments in a homogeneously lighted field was studied as a function of the area and perimeter of the luminance increment. Sixteen targets representing all possible combinations of four values of area and four values of perimeter were foveally presented. Exposure durations were short (25 to 40 msec). Results of both an analysis of variance and linear discriminant analysis indicated that detection probability increases as area increases, but neither variations in perimeter nor perimeter-area combinations produced effects that were significant oyer the experiment as a whole. The linear discriminant analysis revealed individual differences in the effects of perimeter and area on detection probability. Results were contradictory to Kristofferson’s (1957) “element contribution theory” and gave only slight support to Hecht’s (Lamar, Hecht, Shlaer, & Hendley, 1947) “border-quantum theory.”     

Vibrotactile vigilance: The effects of costs and values on signals

Vibrotactile vigilance behavior was examined for the effects on signal detection performance of placing costs on misses and false detections and a positive value on the correct detection of a signal. Analyses over time showing that the frequencies of correct detection and false detection of signals decreased, while response times increased, indicated that increased costs for misses and false alarms lead to poorer correct detection performance, while the value placed on the correct detection of a signal had little effect. The d’ statistic of signal detection theory was invariant with both signal costs and time, while β varied with both factors.These results imply that the performance decrement during a vigil was due to an increased strictness in the criterion (β) the S set for deciding whether or not a signal was present. The cost factors were effective in manipulating performance during the watch by causing changes in the S’s decision criteria. Findings from this study clearly support those predicted by the “Decision Theory” of Swets, Tanner, and Birdsall (1961); this is suggested as perhaps being the best available basis for a theory of vigilance at this time.     

Two operations In character recognition: A partial replication

Subjects carried out a choice reaction time experiment in which they were required to press one lever ifa tachistoscopically flashed numeral was a member of a previously memorized list of numerals and a second lever if it was not a member of the list. The number of numerals in the list was varied from one to four. On half of the trials the numeral was partially masked by a pattern of visual noise. For one group a single fixed pattern of noise was used; for a second group four patterns presented in random order were used. Reaction time from the onset of the numeral to the lever press was found to be a linear function of list size, confirming Sternberg’s hypothesis that the list is scanned serially to determine a match. Partial masking was found to add a constant increment to reaction time for both groups, independent of set size. The increment was equal for both groups. The constancy of the reaction time increase contradicts Sternberg’s results in which the increment was found to be, in part, a function of list size. The results of the present study indicate that one cannot dismiss the possibility that Ss identify the character to the point of labeling prior to an attempt to determine list membership.