Effects of food priming on instrumental acquisition and performance

Four experiments investigated the effects of a priming food reinforcement, given 0 or 75 sec pretrial, on runway performance of rats. The studies differed in the use of between-versus-within-subject designs, and by using food or water as the goal reinforcer. In Experiment 1, using food as the goal reward, subjects primed with food 0 sec pretrial conditioned slower than subjects primed 75 sec pretrial. In Experiment 2, using water as the goal reward, subjects primed with food 0 sec pretrial conditioned faster. These differences were evident on both prefed trials and on nonprefed test trials. Experiments 3 and 4 showed an opposite pattern of results when within-subject comparisons of 0- and 75-sec pretrial intervals were used: Food priming immediately pretrial facilitated food-rewarded running but inhibited water-rewarded running. The results suggest prefeeding has differential effects on acquisition and performance of instrumental behavior, and also depending upon the similarity of the priming and goal reinforcers.     

Do Students with Different Characteristics Take Part in Psychology Experiments at Different Times of the Semester?

ABSTRACT In this study we examined 15 personality and demographic differences between psychology students who took part in experiments at different times of the semester and different times of the day. In general, few significant relations were found and those that did emerge were small in magnitude. Females and freshmen signed up for experiments earlier in the semester. Females took part in their first experiment earlier in the semester, as did students who were Protestant and who came from smaller home towns. Students low in self-consciousness also tended to begin participating earlier. Extraverts participated earlier in the day than introverts. Results generally were consistent with previous findings of differences between research volunteers and non-volunteers. However, it was concluded that because of their small magnitude and inconsistency from site to site, with a few precautions experimenters probably need not be concerned that timing effects threaten the external validity of psychological research outcomes.     

Use of the family adaptability and cohesion evaluation scales in child clinical research

Although the FACES has become a widely used instrument for assessing children's family relations, the possible linearity vs. curvilinearity of its cohesion and adaptability scales has been treated inconsistently by investigators. This study evaluated whether samples of adolescent repeat offenders, young adult prisoners, and adolescent nonoffenders were discriminated better by a linear or curvilinear treatment of the FACES scores. Between-groups comparisons showed that significant effects were observed for each of the three curvilinear measures (cohesion-curvilinear, adaptability-curvilinear, distance-from-center) and only one of the two linear measures (cohesionlinear). These findings support the superiority of a curvilinear treatment of the FACES. In light of these findings, it is suggested that investigators who use FACES evaluate the linearity of the scales and determine whether a linear or curvilinear treatment of the data produces more meaningful results.     

Cerebral control for speech in right-handers and left-handers: an analysis of the views of Paul Broca, his contemporaries, and his successors

According to several recent historical accounts, Broca (1865a) stated that left-handers are the mirror-reverse of right-handers for cerebral control of speech, with the right hemisphere being dominant in left-handers, and the left hemisphere dominant in right-handers. The same accounts then note Broca's error in light of current evidence that the majority of left-handers are left-dominant for speech just as are nearly all right-handers. Eling (1984) has called such statements misrepresentations of Broca's position and has argued that Broca's analysis actually was more compatible with the current view that there is a disjunction, meaning an absence of an intimate anatomical relationship, between cerebral control for handedness and speech. The current paper looks again at Broca's work, describes the context in which his views were first articulated, and traces the development of the mirror-reversal principle. The conclusion is reached that, judged by a narrow reading of the 1865 paper, Broca's views could indeed be construed as an anticipation of the modern disjunction principle. However, judged by a broader reading, by consideration of his other writing, and in the context of the philosophical and scientific tradition that shaped his work, it is suggested that it was the mirror-reversal principle to which Broca was actually disposed.