Overtraining, transfer to proprioceptive control and position reversal

If rats are overtrained on a visual discrimination they generally learn the reversal of the discrimination faster than non-overtrained rats. In position discriminations, however, this effect does not generally hold—indeed several investigators have found overtraining to retard position reversal. One of the important differences between the two types of problem seems to be the presence of irrelevant cues in visual discriminations, and their absence in position discriminations. It is suggested that a second important feature of position discriminations is that overtraining usually causes control of the maze running habit to be transferred from external to proprioceptive stimuli, and that successful reversal cannot normally occur until external control is re-established. In two experiments a study by Krechevsky and Honzik (1932) is repeated with certain modifications, with results that support this hypothesis; and a third experiment provides direct evidence of transfer to proprioceptive control in a T-maze. It is shown that this analysis will explain the apparently conflicting results of all recent position reversal experiments.     

The value of relative-time-spent ratings in task-oriented job analysis

Recent studies have called for the abandonment of the relative-time-spent scale in task inventories. This recommendation is based on findings that the job profile created with the scale data is highly correlated with the profile created from a much simpler “Do you perform this task?” checklist. We examined this issue using 3 inventories and 42 jobs (N=2252). Profile correlations were computed on only the tasks actually performed by incumbents to avoid possibly inflated rs due to including irrelevant tasks. The specificity of task inventory items was proposed as an explanation for the high correlation between the two job profiles. Specificity of items was examined by looking at both the type (job duties versus tasks) and the amount (number of items in job profile and average number of items relevant to each job) of items used in the inventory. Correlations between time spent and checklist profiles were in the .80's and .90's regardless of the number of irrelevant tasks or the specificity of tasks. We agree with previous military research and conclude that the relative-time-spent scale has limited incremental utility beyond a dichotomous checklist.     

Should we study the Hippocratic Oath?

In this commentary on a study by H. Steven Moffic, et al., of the current status of the Hippocratic Oath in medical education, Veatch discusses the relation of the oath to ethical conduct, the meaning of primum non nocere ("do no harm"), and the limitations of practicing Hippocratic ethics.     

The orienting response,and future directions of its development

The orienting response (OR) is a specific behavioral act directed towards extraction of information from the environment. Head and eye movements represent only the tip of the iceberg of internal responses, which includes vascular modifications, EEG changes, and event-related potentials. Two mechanisms of the OR have to be differentiated: voluntary and involuntary. In the event-related potential, such a differentiation is expressed in mismatch negativity (involuntary effect) and processing negativity (voluntary effect). Single unit studies have shown that hippocampal neurones are simulating specific features of the OR as a response to novelty. Repeated presentation of stimuli results in a selective habituation of novelty detectors in hippocampus and of the OR. The trace of a standard stimulus formed at the level of hippocampal neurones matches the features of the standard stimulus and can be called a “neuronal model of the stimulus.” The OR is triggered by mismatch between the test stimulus and the elaborated neuronal model, and is activated by verbal instruction, by reinforcement during the initial stage of conditioned reflex elaboration, and by differentiation of signal and non-signal stimuli. A promising new area of practical application of the OR lies in the evaluation of a corridor of optimal functional state for efficient computer-based learning. Registration of the OR and defensive responses can be used for an objective evaluation of the functional state of the student, or, in a wider sense, of the industrial operator. New avenues of OR research are opened by recent techniques that isolate single-trial event related potentials, and their correlation with autonomic and behavioral manifestations of the OR. The combination of single unit recording with such isolated event related potentials can elucidate the neuronal basis of OR generation. Intracellular recording combined with dye injection can be used for analysis of the synaptic contacts involved in generation of the OR. Integration of macro and micro levels of OR organization can be achieved in a computerized model that can be used for simulation and planning of experiments. A step-by-step improvement of the model will accumulate knowledge about the OR as an important mechanism of information processing.