Effects of feedback and reinforcement in tachistoscopic training on a fault-detection task

This study looked at possible differential effects of feedback and reinforcement on a stimulated fault-detection task. Volunteer college students, 11 females and 13 males, participated in the study. Subjects were assigned to three different groups and tachistoscopically presented with series of slides of intact and faulty cups randomly arranged. Subjects in Group 1 were shown a highly preferred slide following each correct detection (positive reinforcement). In Group 2, subjects received a second, longer presentation of every item responded to and every critical one omitted (knowledge of results). Subjects in Group 3 faced a blank screen during inter-stimulus intervals (practice control). Detection scores along five decreasing stimulus presentation times were recorded. Data indicate the treatment conditions as equally efficient and significantly better than the control condition. However, performance of the control group did improve significantly throughout training which suggests the use of tachistoscope as a training device per se. Commission and omission errors did not differ significantly within treatments, though both types of error were significantly elevated for the control group. A possible dissociation between the effects of reinforcers and feedback is discussed, and experiments which would tax higher levels of information processing are suggested to probe this issue further.

[Quantitative variations of hematological properties during growth in Spanish school children from Barcelona]

A sample of n = 836 male students between 9 and 16 years from Barcelona was analysed for quantitative variations of various hematological characters during growth. The results were compared with a sample of n = 194 adult males between 20 and 45 years. No statistically significant variations were found concerning the levels of calcium, ureic nitrogen, glutamate-oxal-acetat-transaminase (s-GOT), serum albumin and total serum protein. Against that, marked and statistically significant age variations were seen for the levels of alkaline serum phosphatase, glucose, anorganic phosphorus, cholesterol, and uric acid. These variations are without doubt associated with the metabolic processes during growth. Unexplained remain the age variations concerning the bilirubin and lactate dehydrogenase levels. Out of the serum protein fractions only the alpha1- and gamma globulins showed some age variations: The alpha1-fraction increases between 10 and 16 years, the gamma fraction decreases between 9 and 14.