Abstract Introduction/Brief Review of Literature An entire body of theoretical work and a practical framework underlies the contributions of conditioned learning. How humans learn and retain what they do has implications far beyond the academic environment. Among children and adolescents with autism spectrum conditions, for example, conditioned learning experiments employing an aversive unconditioned stimulus (US) have enabled researchers to hypothesize that a dysfunctional amygdala explains both poor facial recognition and chronic anxiety. In these parlous times, when recessionary unemployment trends afflict millions of Americans, human resource professionals cast about for the most efficient methods with which to structure retraining for career change or technological upgrades in the same job setting. Other matters that conditioned learning concepts might address include finding solutions to meet the admirable goals of “No Child Left Behind”. Or for a profession that prides itself on great depth of scientific learning, how do physicians avoid sustained trial-and-error prescribing behavior when there is great uncertainty about the etiology of presenting symptoms? Since much of learning is rather more complex than the classical single S-R experiments of Pavlov and Skinner, the field has progressed to assess what happens when humans are presented with dual stimuli, of which none or one has been previously conditioned. In the context of the experiment conducted, learning success or failure in a block presentation can theoretically be attributed to the operation of pre-conditioning, selective attention, surprise, and categorization. The basic blocking model involves the compound conditioned stimulus, consisting of both A and B. Mere proximity in time does not guarantee conditioning, especially if an association between only A and the US had already been established beforehand. When presented singly afterwards, in fact, A is therefore more likely to provoke the conditioned response of interest. (Kamin, 1967, as cited in Roitblat, Bever, & Terrace, 1984). Roitblat et al. (1984) explain the processes underlying success or failure to provoke the desired conditioned response by reference to information processing and rehearsal. The first infers that humans and indeed any other animal processes information from their environment to try and make sense of the contingency it is presented with (citing Kamin, 1969). Citing Wagner (1978, 1981), the authors also offered up the idea of associative learning and rehearsal, the latter taking place for stimulus B in the above blocking model only when the state of the US changes (presence/absence or intensity) contingent on B. In the course of the Assignment 2 experimental design, however, there is only one sequence (Phase 1: A+, Phase 2: AB+) where participants had effectively received a “pre-trial” with one food of the stimulus pair. Presumably, this variable designator means both CS’s are allergens. There being no conflict in that regard, blocking should have no adverse effect on learning rate. The GH(-), T(-) and V(-) stimuli screens occur in both phases but with no reinforcement. Neither pre-trial nor blocking affects learning one way or the other. Over a long series of runs, therefore, the results should be purely random or 50-50 odds. Other constructs that might be relevant to