Cardiovascular responses to avoidance conditioning in the dog: Effects of alpha adrenergic blockade

Laboratory dogs were trained to press a response panel to postpone shocks during daily one-hour avoidance conditioning periods. Each dog was also confined in the experimental environment for 5 hours prior to the avoidance periods. Blood pressure and heart rate were monitored continuously during these experiments from chronically indwelling arterial catheters. Extended training resulted in the emergence of a cardiovascular response pattern during the pre-avoidance interval characterized by gradual increases in blood pressure together with decreases in heart rate. Elevations in both blood pressure and heart rate were sustained during the avoidance periods. During sessions in which alpha adrenergic activity was suppressed by phenoxybenzamine, absolute levels of blond pressure were found to be lower than during control (non-drug) sessions, but a progressive rise in blood pressure continued to be observed during pre-avoidance. These results suggest that sustained cardiovascular responses during avoidance periods are associated with activation of the sympathetic nervous system, but that the gradual rise in blood pressure during pre-avoidance is due to other factors.     

Selective looking with minimal eye movements

Neisser and Becklen (1975) showed that one of two visually superimposed events could be followed without interference from the other. Neisser and Becklen allowed their subjects to move their eyes without restriction. The present experiment eliminated the possibility that the tracking eye movements of the subjects, which could have been used to maintain the stability of the event on the retina, were instrumental in following the desired event. The experiment of Neisser and Becklen was essentially replicated with one exception: subjects were required to fixate a spot in the center of the visual field during one-half of the trials. It was no more difficult for subjects to follow either a single event or one of two superimposed events when fixation was required. The suggestion was made that eye movements do not initiate a perceptual act, but rather are dependent upon perceptual anticipations.     

Periodicity pitch perception and its upper frequency limit in cats

We have established a procedure for behavioral assessment of periodicity pitch perception in the cat. This procedure requires the training of cats to make a differential response to two different pure tones, and then testing for the transfer of learning when complex stimuli known to produce periodicity pitch sensations in humans are substituted for the pure tones. Complex stimuli consisted of three to five harmonically related frequencies of the same amplitude and phase. Eight cats were the subjects of these experiments. Two of them were controls. It is demonstrated here that cats do perceive periodicity pitch. We also used this procedure to measure the upper frequency limit of periodicity pitch perception for two cats. The frequencies tested were 100, 200, 300, 400, 600, 800, 900, and 1,200 Hz. The data indicate that the upper frequency limit of periodicity pitch perception in the cat is on the order of 600 to 800 Hz. There is a trend of decreasing prominence of the perception of periodicity pitch as the component frequencies are increased. These results are parallel to the human psychophysical data.     

Lump detection in simulated human breasts

Sixteen observers palpated silicone models of human breasts containing lumps 1.6-12.1 mm in diameter. Detectability depended on the size of the lump, producing a systematic psychometric function. In eight observers who participated in three or more sessions, performance improved with practice, with most improvement occurring within one or two 26-trial sessions. Three-week retention measures disclosed no appreciable decrease in performance, but a significant correlation was found between the number of lumps detected and duration of trial (p < .01). There was no difference in performance between four observers who used their preferred hands and four observers who used their nonpreferred hands. These data establish that examination of breast models for the detection of lumps simulating cancer is a task amenable to experimental analysis.     

Syllabic vs segmental perception: On the inability to ignore “irrelevant” stimulus parameters

C. C. Wood and R S. Day have shown that reaction times (RT) to target segments within a syllable are significantly longer when the unattended segment in the syllable (either stop consonant or vowel) is varied randomly than when it is held constant. This has been taken as evidence for the perceptual unity of a stop con sonant-vowel syllable. However, this conclusion could be accepted with much more confidence if it could be shown that random variation in unattended segments does not cause an increase in RT if the unattended segments are not in the same syllable as the target segment. The present study, using bisyllabic natural speech stimuli, (1) reconfirms Wood and Day’s results, but (2) finds that random variation in unattended nontautosyllabic segments also results in significantly longer RTs than without nontautosyllabic variation. Segmental vs syllabic speech perception thus remains an open question.     

There's method in our madness: Interpersonal attraction as a multidimensional construct

The convergent validity and number of dimensions common to six measures of interpersonal attraction (three verbal and three nonverbal) were explored in this investigation. Convergent validity was found within verbal and nonverbal modes of measurement, but not between modes. No general factor was found to be common to the six measures of attraction. It was, therefore, concluded that method bias influences experimental results, threatening the comparability of results from research programs using different modes of measuring attraction. The results also question the assumption that social attitudes, such as attraction, are closely related to behavior, and imply that predictions derived from theories based on different modes of measuring attraction will have unequal utility.     

Attention to pure tones

Listeners were required to detect increments of intensity or frequency in trains of pure tone bursts under different conditions of attention. The data were analysed taking into account contralateral events when more than one stimulus train was present. Marked changes in d' and β were found and the changes were positively correlated.

If targets are rare and attention is divided the values of β and d' are the same as in undivided attention provided that the contralateral event is a correct rejection, but fall if the contralateral events are hits or false alarms. If targets and non-targets are equi-probable no such difference is found. The data suggest that the observers can make use of the statistical properties of the stimulus sources. The results are compared with those in recent experiments using pure tones in a discrete trial paradigm and in experiments using semantic stimuli.     

Hardware and software evolution of an adaptive ability measurement system

A software system for the administration of six different strategies of adaptive ability tests in a variety of formats was developed both on a large-scale time-sharing system and on a real-time minicomputer system. Factors influencing both hardware selection and software design are discussed.     

The use of on-line computers in psychobiology

This paper examines several areas in the use of laboratory computers in psychobiology, specifically how they are being used, the problems in languages and software, in interfacing computers to experimental configurations, and in the hardware involved. The paper defines the experimental tasks and data requirements which tend to distinguish computer usage in physiological research from other areas of psychology and the tasks which absolutely necessitate the use of a computer and in what mode. Finally we present our views of the dangers of computer use and misuse and make our own subjective evaluation of how well computers are living up to their end of the bargain, how well scientists are doing at their end, and where we should go from here.