Glucose and cognitive performance : the effects of glucose on memory and sustained attention : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University
The effects of glucose on tasks of declarative memory, and sustained attention were examined. These effects were also investigated with regard to the age of the participant. Standard glucose and placebo conditions were run and also a natural history condition to analyse the possibility of a placebo effect. Twelve young and twelve older adults participated in the study. Over three separate morning sessions, participants ingested either the glucose or the placebo drink, or nothing for the natural history condition, and completed the cognitive tasks. The between-group factor was age of the participant (young or older adult). The within-group factor was the type of drink ingested (glucose, placebo, or natural history). The effects of glucose on the sustained attention task were investigated over time, divided into 10 × 2 min periods. No effects of drink were found in regard to overall task performance for either age group. There was one main effect for period on one measure of the sustained attention task. There was also an associated interaction effect for this measure. Trends in the data pointed towards the possibility of the existence of a placebo effect. The placebo condition yielded consistently better performance than the other two conditions on most tasks. These results were discussed in light of the possible existence of a placebo effect, and the condition-specific effects of glucose.