A method for electronically monitoring the ambulatory activity of honeybees under dark conditions

An electronic apparatus using infrared beams for monitoring the movements of individual bees under dark conditions is described. The searching behavior of workers in an arena was monitored over 2-h periods. Mean ambulatory velocity for one bee over a distance of 100 mm was 45.6±1.51 mm/sec (n=45). Thigmokinesis and temporal activity patterns are illustrated.     

Differential visual field-interhemispheric transfer: can it explain sex and handedness differences in lateralization?

104 men and women were tested for visual field-hemispheric transfer of spatial information on a dot-localization task. Right-handed subjects showed significant improvement when stimuli were presented to the left visual field of the right hemisphere (LVF-RH) after practice on the same task presented to the right visual field of the left hemisphere (RVF-LH) first. No improvement was found when the task was presented in the reverse order (LVF-RH first followed by RVF-LH). It was concluded that, for right-handers, transfer of spatial information to the right hemisphere is facilitated while transfer to the left hemisphere is inhibited. Left-handed subjects demonstrated no significant improvement in either condition, suggesting inhibition or lack of transfer of spatial information in either direction. No sex differences were found in either right-handed or left-handed subjects. The findings suggest that there may be different mechanisms underlying the similarities in functional lateralization of women and left-handers.     

An on-line assessment of causal reasoning during comprehension

Fletcher and Bloom (1988) have argued that as readers read narratives, clause by clause, they repeatedly focus their attention on the last preceding clause that contains antecedents but no consequences in the text. This strategy allows them to discover a causal path linking the text's opening to its final outcome while minimizing the number of times long-term memory must be searched for missing antecedents or consequences. In order to test this hypothesis, we examined the reading times of 25 subjects for each clause of eight simple narrative texts. The results show that: (1) causal links between clauses that co-occur in short-term memory (as predicted by the strategy) increase the time required to read the second clause; (2) potential causal links between clauses that never co-occur in short-term memory (again as predicted by the strategy) have no effect on reading time; and (3) reinstatement searches are initiated at the end of sentences that are causally unrelated to the contents of short-term memory or that contain clauses that satisfy goals no longer in short-term memory. These results support the claim that subjects engage in a form of causal reasoning when they read simple narrative texts.     

Rapid processing of the meaning of sentences

It has been shown (Fischler & Bloom, 1979) that sentence contexts facilitate a lexical decision task for words that are highly likely sentence completions and inhibit the decision for words that are semantically anomalous sentence completions. In the present experiment, the sentence contexts were presented 1 word at a time, at rates from 4 to 28 words/sec. The facilitation for words that were likely sentence completions was marginal at the slower rates and absent at higher rates. In contrast, the inhibitory effects of semantic anomaly were apparent at all presentation rates. Several analyses suggested that the sentence contexts were becoming ineffective at the very highest presentation rates, but the high rates at which the sentence contexts still affected word recognition were taken as evidence that semantic information accrues at an early stage of sentence processing. Implications for Posner and Snyder’s (1975) theory of attention and for models of reading were discussed.     

Completion norms for 329 sentence contexts

Completion responses were collected for two sets of sentence contexts, which were designed to produce different distributions of probabilities for the primary responses. The subject population consisted of undergraduate college students. For each context, responses and their respective probability of occurrence are listed, and an index of the primary responses is provided. It is hoped that these normative materials will facilitate comparison among future studies of the effects of sentence contexts on word processing.