The symmetrical maze: An automated closed-field test series for rats

An automated “intelligence” test for rats is described. Supporting data indicate that this maze-problem series is sensitive to hypothyroidism-induced learning deficit and sex differences. Comparisons between this new problem set and the Rabinovitch-Rosvold (1951) closed-field tests are presented with respect to difficulty, internal consistency, and test-retest reliability.     

Visual on- and off-latencies and handedness

Ten Ss served in this experiment, five right-handed and five left-handed. Every S was tested in a perceived-order situation and by the up-and-down method to determine the relative on-latency for a visual test stimulus. i.e, (ON-Lat for lest stimulus involving right hemisphere- ON-Lat for standard stimulus involving left hemisphere) and to determine a similarly defined relative off-latency for the same test stimulus. The algebraic difference between the relative on-latency measure and the relative off-latency measure was then found. Data from a previous study had suggested that this “on-off difference” was characteristically positive for left-handed Ss and negative for right-handed Ss. The present data agree. The left-handed Ss were found to differ significantly from the right-handed Ss in the magnitude of the on-off difference. This outcome appears important as a possible clue to functional interhemispheric differences related to handedness.     

The war and military obligation: Private attitudes and public actions1

The relationship between attitudes toward the Vietnam war and willingness to sign a strongly worded and publicized antiwar resolution was studied in a random sample of 131 male college seniors at a selective liberal arts college. Level of opposition to the war did not fully explain why many strongly antiwar subjects did not sign the resolution. With level of opposition to the war held constant, personality measures and other attitudes differentiated between signers and nonsigners It is hypothesized that the disposition to act publicly in support of private attitudes is a separate variable, which may be independent of the content and intensity of attitudes Studies of “activism” should distinguish more sharply between private attitudes and public actions.     

Similarity of cardiac CR forms in the rhesus monkey during several experimental procedures

Cardiac rates of rhesus monkeys were observed in a variety of different conditioning procedures, each of which involved a visual stimulus (CS) followed by an electric shock (US). With a 30-sec CS, cardiac rate accelerated rapidly after CS onset, reached a maximum in the middle of CS, and decelerated thereafter, with a terminal CS rate often at the level of, or below, pre-CS levels. A similar biphasic cardiac rate response in CS was also observed under subsequent exposure to intermittent pairings of CS and US, avoidance of US, response-produced termination of US, and when CS-US pairings were superimposed upon an avoidance baseline, even when CS duration was varied from 12 to 60 seconds. The unusual regularity of cardiac rate responses in several different procedures may result from one or more of these factors: (a) characteristics of the rhesus monkey, (b) initial exposure to Pavlovian conditioning, or (c) the uniformity of measurement of cardiac rate employed in this study.     

Size and distance judgments under reduced conditions of viewing

Magnitude estimations of the size and distance of a variable relative to a standard were obtained in the absence of distance cues. Estimates were provided by different groups under three conditions: (a) physical size and distance variant, visual angle of the variable constant and equal to the standard, (b) physical size constant, physical distance and visual angle of variable changing, and (c) physical distance constant, physical size and visual angle of the variable changing. The results in both experiments were very similar. In each case both size and distance estimates conformed to relative visual angle. The results are applied to an analysis of size-matches that are obtained when distance cues are eliminated.     

The character in the hole experiment: Interaction of forward and backward masking of alphabetic character recognition by dynamic visual noise (OVN)

In the present study we consider the question of interaction between the forward and backward masking effects of dynamic visual noise (DVN) on the recognition of alphabetic characters composed of the same type of dots as those composing the DVN. The results of our experiments indicate that the two effects strongly interact so that both the duration and magnitude of the combined effect is far greater than would have been predicted by an algehraic model. Speculations about possible explanatory assumptions are presented.     

Persistent behavior maintained by unavoidable shocks

Squirrel monkeys were trained on a multiple schedule in which 10-min periods on a continuous shock avoidance schedule, indicated by a yellow light, alternated with 10-min periods on a 1.5-min variable interval schedule of food reinforcement (VI 1.5). A white light indicated that VI 1.5 was in effect, except for the middle 2 min of the period on VI 1.5, in which a blue light appeared and terminated with the delivery of a 0.5-sec unavoidable shock. Stable response rates developed in the avoidance and VI 1.5 components. However, the highest response rates occurred in the blue, preshock stimulus. A series of experiments showed that responding in the blue stimulus persisted even when responding had been extinguished on both the VI schedule of food reinforcement and the shock avoidance schedule. Responding in the blue stimulus ceased when the blue stimulus terminated without shock or when it terminated with a response-contingent shock. Each time responding ceased, it was restored by terminating the blue stimulus with an unavoidable shock. When the blue stimulus was on throughout each session and unavoidable shocks were delivered at regular 10-min intervals, responding was well maintained. These results show that in monkeys that have been trained on a continuous avoidance schedule, unavoidable shocks can maintain responding even under conditions where responses have no programmed consequences.