No abstract

OBJECTIVES. The incidence, type, severity, and costs of crash-related injuries requiring hospitalization or resulting in death were compared for helmeted and unhelmeted motorcyclists. METHODS. This was a retrospective cohort study of injured motorcyclists in Washington State in 1989. Motorcycle crash data were linked to statewide hospitalization and death data. RESULTS. The 2090 crashes included in this study resulted in 409 hospitalizations (20%) and 59 fatalities (28%). Although unhelmeted motorcyclists were only slightly more likely to be hospitalized overall, they were more severely injured, nearly three times more likely to have been head injured, and nearly four times more likely to have been severely or critically head injured than helmeted riders. Unhelmeted riders were also more likely to be readmitted to a hospital for follow-up treatment and to die from their injuries. The average hospital stay for unhelmeted motorcyclists was longer, and cost more per case; the cost of hospitalization for unhelmeted motorcyclists was 60% more overall ($3.5 vs $2.2 million). CONCLUSIONS. Helmet use is strongly associated with reduced probability and severity of injury, reduced economic impact, and a reduction in motorcyclist deaths.

No abstract

Tulving and Thomson's encoding specificity effect was examined as a function of grammatical class and concreteness of the cues. Experiment 1 tested the hypothesis that a recognition cue of the same grammatical class as the input cue should produce better recognition performance than one that changed grammatical class. This hypothesis was not supported. Experiment 2 showed that grammatical class and concreteness of the input cues affect the encoding specificity phenomenon. The effect was observed only for concrete noun cues. This was mostly attributable to concreteness. The results suggested that concrete encoding cues produce a "specific" memory trace which can best be retrieved via the original encoding cue, while more abstract cues produce a trace that is not cue-dependent. The interpretation was that a cue-target word pair is encoded as a unit in memory and that the best access to the unit is provided by the more salient (concrete) member of the unit.

Tulving's encoding specificity principle was examined in two experiments. The main comparison concerned the relationship between the retrieval cue or recognition context and input cue. The presumed encoding of the to-beretrieved or to-be-recognized item was either semantically the same as or different than its encoding during input. Experiment 1 demonstrated encoding specificity (same cues were superior to different cues) under a typical free-responding output condition and the elimination of that effect under a forced-choice procedure. These data suggested that criterion biases may be the source of the effect, or that forced responding led to extended item processing. A second experiment employing signal detection theory procedures, however, showed both criterion and discriminability differences. To account for these results a stimulus sampling theory of encoding and retrieval similar to Bower's was proposed. The model was a modification of the generation-recognition model, which can account for the apparent lack of isomorphism between the episodic and semantic representation of the word.