Early selective-attention effect on evoked potential reinterpreted

In a dichotic listening situation stimuli were presented one at a time and at random to either ear of the subject at constant inter-stimulus intervals of 800 msec. The subject's task was to detect and count occasional slightly different stimuli in one ear. In Experiment 1, these ‘signal’ stimuli were slightly louder, and in Experiment 2 they had a slightly higher pitch, than the much more frequent, ‘standard’, stimuli. In both experiments signals occured randomly at either ear. Separate evoked potentials from three different locations were recorded for each of the four kinds of stimuli (attended signals, unattended signals, attended standards, unattended standards). Contrary to Hillyard et al. (1973), no early (N₁ component) evoked-potential enhancement was observed to stimuli to the attended ear as compared with those to the unattended ear, but there was a later negative shift superimposed on potentials elicited by the former stimuli. This negative shift was considered identical to the N₁ enhancement of Hillyard and his colleagues which in the present study was forced, by the longer inter-stimulus interval used, to demonstrate temporal dissociation with the N₁ component. The ‘Hillyard effect’ was, consequently, explained as being caused by a superimposition of a CNV kind of negative shift on the evoked potential to the attended stimuli rather than by a growth of the ‘real’ N₁ component of the evoked potential.     

Depth of processing: When the principle of congruity fails

Two factors, level of processing (Craik & Lockhart, 1972) and congruity (Schulman, 1974), known to have large effects on the recall of experimenter-provided responses to questions, were examined in a series of five incidental learning experiments using subject-generated responses. The data show that manipulation of level of processing has the same effect on recall of subjectgenerated responses as it does on experimenter-provided responses. However, the effect of congruity is reversed for subject-generated responses. The data suggest that the difficulty of generating unrelated responses (“incongruous“ items) may account, at least in part, for the failure of the “principle of congruity“ with subject-generated responses.     

Comment on "personality organization as an aspect of back pain in a medical setting".

The methodology and results of a recent investigation by Louks, Freeman, and Calsyn (1978) are reviewed. It is demonstrated that the results may have been confounded by inappropriate experimental procedures. Regardless of the methodological deficiencies associated with the experimental procedures, the results do not provide adequate support for the continued differentiation of individual low back pain patients with respect to the etiology of their pain. It is suggested that psychologists may best contribute to the assessment and treatment of individual pain patients by developing actuarial rules regarding the pain-related behavioral characteristics shared by members of various patient subgroups and the specific treatments to which subgroup members best respond.     

On the structure of motor recognition memory

Two experiments determined the influence of the range and number of auditory sensory consequences, associated with a rapid timing task, on the development of motor recognition. Experiment 1 observed no beneficial effect upon subsequent movement-transfer performance from experience with the criterion-movement-time sound compared to experience with either a narrow or a wide range of sounds that bracketed the criterion sound (not including the criterion); 60 sound trials prior to transfer did not produce better transfer than did six sounds. The second experiment examined transfer outside of the range of previous listening experience by having subjects transfer to one of two possible criterion movement times after having received either constant, or one of two types of variable, listening experience. Transfer performance was influenced by the amount of variability in listening experience. These results were seen as support for a schematic representation for motor recognition memory (Schmidt, 1975)     

AN INDEX FOR ASSESSING WEIGHT CHANGE IN CHILDREN: WEIGHT/HEIGHT RATIOS1

Weight and height data from two studies were recomputed, and original data were computed using a Weight Index formula that accounts for the interaction of actual weight/height changes in growing children and compares this ratio with that of normed weight/height ratios for equal-aged children. Recomputing the data of one study showed that the Weight Index is a more sensitive procedure for assessing long-term behavioral treatment of obesity for girls than weight alone. Recomputing the data of a second study showed that the Weight Index formula is consistent for boys and girls and is a more sensitive procedure for assessing long-term effects of a variety of medical treatments for obesity than the Ponderal Index or weight alone. Computation of the data for 17 “normal” children in a preschool class showed a zero Weight Index score before and after a six-month interval elapsed without treatment. The procedure may be useful in assessing ponderosity or anorexia over intervals of six months or more with growing children or difference between actual and normed weight over shorter intervals.     

Behavior of the rat after removal of the neocortex and hippocampal formation

After surgical removal of the neocortex and hippocampal formation, rats retained most of the movement patterns of locomotion, climbing, grooming, feeding, and fighting. However, forepaw immobility during swimming was abolished. Feeding behavior was suppressed temporarily but recovered partially. The distinctive postures of sleep and walking and a circadian rhythm of motor activity were retained. However, behaviors were often not performed at the appropriate time and place. The normal sequence of grooming behavior was disrupted; food hoarding and social behavior were essentially abolished. Removal of the neocortex alone had much the same effect as removal of neocortex and hippocampus together. Removal of hippocampus alone produced only a mild disruption of behavior. It is suggested that ascending nonspecific projections to the cerebral cortex play an important role in the moment-to-moment control of behavior but are not essential for the sleep-waking cycle.     

Exploration and avoidance in rats with lesions in amygdala and piriform cortex

Lesions localized to specific areas of the amygdala and overlying cortex in rats produced differential effects in several behavioral tasks. Three different types of lesions were tested: central, basolateral, and cortex lateral to the amygdala. Lesions restricted to the central nucleus produced increased activity on all parameters studied in an open-field test, but the other two groups were not changed. In one-way active avoidance all three groups with lesions showed deficits. The most pronounced change was observed in the central group. All groups showed the same degree of retention loss, but in forced extinction of one-way active avoidance after retraining, the cortical and basolateral groups were most defective. A fear-reduction hypothesis is proposed for the central lesion. The basolateral and cortical areas may be more specifically involved in passive avoidance behavior.     

Reaction time and probability on isolated terms

The reaction-time probability effect on isolated trials was found to be asymmetrical in an experiment on 64 college students. There was a large drop in RT for a high-probability probe trial embedded in a block of low-probability trials, but a much smaller rise for a low-probability trial embedded in high-probability trials. Thus, low- but not high-probability responses seem to be influenced by characteristics of the trial block. If the basis of the probability effect were the strategic placement of the criterion for response initiation, symmetrical results should have been obtained. A motivational account which accords with the present data is that the subject is ordinarily willing to prepare but is averse to doing so in some (not entirely specified) low-probability circumstances.