Skill Acquisition and the LISP Tutor

An analysis of student learning with the LISP tutor indicates that while LISP is complex, learning it is simple. The key to factoring out the complexity of LISP is to monitor the learning of the 500 productions in the LISP tutor which describe the programming skill. The learning of these productions follows the power-law learning curve typical of skill acquisition. There is transfer from other programming experience to the extent that this programming experience involves the same productions. Subjects appear to differ only on the general dimensions of how well they acquire the productions and how well they retain the productions. Instructional manipulations such as remediation, content of feedback, and timing of feedback are effective to the extent they give students more practice programming, and explain to students why correct solutions work.     

The use of a decision-based forgiveness intervention within intergenerational family therapy

The intervention presented here links intergenerational theory and therapy with a step-by-step forgiveness strategy. Forgiveness is defined from a cognitive perspective so that it can be applied within a family-of-origin session. In practice, the forgiveness strategy has been effective in breaking dysfunctional patterns from the past that have been carried into the new family. Long-term effects of forgiveness are analysed through a case study that includes a six-year follow-up of a family-of-origin forgiveness intervention.     

Perforant path activation modulates the induction of long-term potentiation of the schaffer collateral--hippocampal CA1 response: theoretical and experimental analyses

In one computational model of hippocampal function, the entorhinal cortical input to CA1 is hypothesized to play a key role in the ability of CA1 to decode CA3 recodings. Here, we develop a modification of this CA1 decoder hypothesis that is applicable to several computational theories of hippocampal function, and then we electrophysiologically investigate one assumption of this new hypothesis. First, using biologically realistic estimates, we calculate that CA3-induced CA1 excitation is too high and that inhibition plausibly plays a role in this CA1 decoder model. Thus motivated, we turn to a physiological demonstration to substantiate the plausibility of the proposed mechanism. Using the rat hippocampal slice, we examine an interlaminar interaction between the distal perforant path input to hippocampal CA1 stratum moleculare and the more proximal Schaffer collateral input to stratum radiatum. Perforant path activation provides sufficient inhibition to block homosynaptic long-term potentiation elicited by a suitably strong stratum radiatum input. For this interlaminar interaction to be most effective, perforant path activation must both precede and follow Schaffer collateral activation. Perforant path-evoked inhibition in CA1 can thus serve as a viable mechanism in the learned decoder theory of hippocampal CA1.     

An Evaluation of the Cross-Cultural Validity of Holland's Theory: Career Choices by Workers in India

The current study evaluated the cross-cultural validity of Holland's (1985) theory through internal and external analyses based on the responses of 172 natives of India who completed the Vocational Preference Inventory (VPI) and measures of job and occupational satisfaction. Internal consistency estimates for Holland dimensions, intercorrelations among participants' vocational interest scales, and the results of a randomization test (Tracey, 1997) all provide evidence for the internal structure of the VPI with Indians. However, the VPI did not exhibit high external validity. Further, multiple regression results indicated that congruence, consistency, and differentiation did not predict job or occupational satisfaction, suggesting cross-cultural boundaries on Holland's theory itself. Finally, we assessed and found limited conceptual and linguistic equivalence of measurement of the VPI in India. The assumptions of Holland's theory in light of the current findings are discussed.     

Coding strategies,perceptual grouping,and the “variability effect” in free recall

Three experiments examined the effects of constant vs. varied input of letter strings on recall, and then examined the effects of such training in the learning of new lists of letter strings. Letter strings were constructed from pairs of trigrams spatially grouped, and were presented either consistently or with different spatial groupings on successive presentations. In Experiments I and II, varied input produced substantially greater recall than constant input. When transferred to a new list of letter strings, containing either the same general structure or a new scrambled structure, recall of the second list was determined primarily by conditions of first-list input, and unaffected by second-list structure. Although the "variability effect" did not appear in the training phase of Experiment III, Varied input led subjects to regroup or integrate the letter sequences more frequently and produced similar transfer effects as in Experiments I and II.     

Conditioned taste aversions: Two-stimulus tests are more sensitive than one-stimulus tests

Weanling and mature rats were presented with saccharin or saline solutions for 1 h on alternate days. Following exposure to saccharin, rats were injected with 0, 21, or 37 mg/kg of cyclophosphamide. Injections had no significant effect on saccharin preference in one-stimulus tests, but had a highly significant effect in two-stimulus tests.     

Brightness of paired photic pulses with pulse duration and separation varied

The brightness of pairs of photic pulses, differing in pulse duration and pulse separation. was measured. The data were in general agreement with the neurophysiological model of Bishop and Clare. Pulse duration appeared to have little systematic influence on the shape of the curves. Time between onset of the first and second pulse appeared to be a prime factor determining the receptivity of the cortex to the second pulse. The two pulses were seen as single below about .03 sec separation. The second pulse was always judged brighter than the first.