On the Characteristics of Sustained Attention Test Performance

Most psychometric tests assessing sustained attention are characterized by a specific presentation mode: Many items are presented simultaneously and the test takers are required to constantly process and react to them until the testing time is up. The aim of the present study was to look into two mechanisms that potentially underlie performance in these tests: The ability to focus on the currently relevant item and the ability to preprocess upcoming items to prepare for upcoming actions. In order to assess both abilities, the d2-R test of sustained attention was modified and its stimulus arrangement (single, blocks vs. rows of stimuli) was manipulated. The measure of focusing was unreliable and unrelated to performance in standard sustained attention tests. However, the data indicated a strong preview benefit. That is, the test takers preprocessed upcoming items when they got a valid preview of them, which considerably enhanced performance. Moreover, interindividual differences in the preview benefit proved to be internally reliable as well as reliable in retest and were substantially related to performance in three conventional sustained attention tests. We conclude that preprocessing constitutes an important component of performance in sustained attention tests and most likely represents a stable cognitive ability rather than a strategy.

Olfactory memory capacity of the cricket Gryllus bimaculatus

Olfactory learning in insects is a useful model for studying neural mechanisms underlying learning and memory, but memory storage capacity for olfactory learning in insects has not been studied. We investigate whether crickets are capable of simultaneously memorizing seven odour pairs. Fourteen odours were grouped into seven A/B pairs, and crickets in one group were trained to associate A odours with water reward and B odours with saline punishment for all the seven pairs. Crickets in another group were trained with the opposite stimulus arrangement. Crickets in all the groups exhibited significantly greater preference for the odours associated with water reward for all the seven odour pairs. We conclude that crickets are capable of memorizing seven odour pairs at the same time.

Associative learning: Stimulus arrangement and response consistency

Studies on associative learning in normals and patients need appropriate dependent measures which are sensitive enough to reflect stimulus-specific responses and also consider the context in which the conditioning takes place. Patient's fear responses, once acquired, seem to be maintained by specific cognitive biases such as individual belief systems and a tendency to stay consistent with their previous judgments.