The development of same and different judgments

Junior kindergarten children, third-grade children, and college students were given a simultaneous pattern discrimination task, with simple and complex patterns, under either unlimited or limited (150 msec) viewing time. Under unlimited viewing, RTs to same patterns were faster than to different patterns for younger children and older males. Under limited viewing, same and different RTs were equivalent, but more errors were made in judging different patterns by all age groups. The RTs were longer to complex than to simple patterns, but the increase was differentially less for the youngest Ss, especially on same pairs. Since this age difference was found under both limited and unlimited viewing, it was not attributable to age differences in perceptual scanning strategies. The same-different asymmetry in RT under unlimited viewing and in error rate under limited viewing confirms across a wide age range previous findings with adults using codable stimuli. A two-process model for same and different judgments appears to be required, although young children may have had a response bias for same in Expt II.     

Effects of manipulating incentive visibility during the baiting phase of delayed-response problems

Rhesus monkeys were given 960 delayed response (DR) problems. The incentive was either visible or not visible during the baiting phase of each problem, and a 0-, 5-, 10-, or 20-sec intraproblem delay was imposed. Performance was substantially better when the incentive could be seen during the baiting phase. When the incentive was visible during baiting, at all stages of training performance decreased as a function of increased chance levels after short delays, and the rate of improvement with training was comparable after each of the four intraproblem delays. When the incentive was not visible during the baiting phase, an inverse relationship between performance and delay duration became evident only during the later stages of training. On the initial problems performance was at chance levels, and although improvement with training was evident, the rate of this improvement was inversely related to delay duration. The findings were interpreted in terms of Fletcher's orienting response analysis of DR performance.     

Cardiovascular responses to acetylcholine: Effects of pentobarbital and autonomic blocking agents

The effect of acetylcholine chloride (ACh) on heart rate (HR) and blood pressure (BP) was studied in four dogs, awake and under anesthesia by means of pentobarbital sodium. In the awake dog, ACh caused a triphasic change in HR—a rise, fall and secondary rise. The BP showed an initial gradual fall followed by a secondary precipitous fall coinciding with the fall in HR, and then return to base line. Anesthesia accentuated the precipitous fall in HR due to ACh, and narrowed the pulse pressure during the initial fall in BP due to ACh. The effects of atropine sulphate, propranolol and d-tubacurarine on the above were studied, indicating the roles of the sympathetic and parasympathetic systems in mediating the HR and BP reactions to ACh in the awake state and under pentobarbital sodium anesthesia.     

ROLE PERCEPTIONS IN PERU1

Perception des râles au Pérou. — Le Différentiateur de Rôle (RD) a été utilisé pour étudier comment les Péruviens (N = 161) perçoivent les rôles. Les analyses factorielles font apparaître cinq facteurs de comportement identiques pour chacune des deux formes de l'instrument qui ont été utilisées. Une analyse factorielle (two-mode factor analysis) à 6 types de sujets pour chacune des deux formes, mais il n'y a pas de différences majeures dans les structures de réponses par rapport aux facteurs de comportement. Les échantillons sont supposés provenir de la même population. Les résultats sont cohérents avec l'hypothèse selon laquelle des normes de conduite clairement définies sont liées aux différences dans le statut social des paires de rôles qui reflètent le caractère hiérarchique de la société. l'hypothèse d'une invariance interculturelle de la structure factorielle des normes de conduite est confirmée. Les AA. résument brièvement les différences essentielles qui apparaissent dans la perception des rôles chez les Américains, les Grecs et les Péruviens.     

The anatomy of free recall

The relative importance of various covert cues used in free recall is inferred on the basis of conditional probabilities of free recall given success vs failure of cued recall of the same material. Thirty-six names associated with pictures arranged in a 6 by 6 matrix were learned. A free recall test of names was followed by cued recall of names, with pictures, positions, or joint pictures and positions used as cues. Matching tests based on these cues were also administered. The tests were given at one of two stages of training, immediately or after 2 days. Pictorial and position cues are equally well encoded, but pictorial cues are less accessible and, therefore, relatively more useful in cued recall than in free recall. Position and pictorial information related to the names appears to be encoded and forgotten independently, and there is no evidence for summation of subthreshold encoding effect.     

The effects of irrelevant relations on the processing of sequential patterns

Letter series completion problems varying along location of irrelevant relations (beginning, end, none) were presented to 24 Ss. A repeated-measures analysis of solution times and errors revealed that irrelevant relations at the beginning of series produced the longest latencies and the most errors. Using a pattern induction/sequence production model of serial processing, an error analysis showed production error rate remained constant across treatments, while pattern induction errors varied with confusion location. The results indicate that the difficulty of sequential processing varies with irrelevant relations only during the pattern induction phase. The findings also support a left-right generate-and-test model of pattern induction for the task.     

Extensions of factorial solutions

A method is developed for extending any type of factor solution to new tests. The theoretical basis for this approximating scheme is thoroughly investigated, and then a simplification in the technique is introduced for practical purposes. An example is presented which illustrates the procedure of extending a factor solution to three new tests simultaneously.