The visual attentional blink reflects constraints on temporal visual processing, not just a lapse of visual memory

Background: Most theories related to the attentional blink (AB), defined as the refractory period of 300 to 500 msecs following a conscious visual identification, during which a second detection task is impaired, argue that limitations of 'visual working memory' (VWM) underlie the phenomenon rather than suppression of attention. The current study examined the relationship between performance on an AB task and classical measures of visual and auditory memory and executive function (EF). Methods: Fifty-one adult volunteers completed the AB task but only 27 of these also completed an extensive battery of traditional measures of short-term and working memory, processing speed and EF. Correlation and regression methods were used to analyse the data. Results: Bivariate correlation showed a significant relationship between AB duration and non-verbal intelligence and processing speed. Multiple regression analysis demonstrated that four factors (non-verbal intelligence, letter-number sequencing, visual search and visuo-spatial recognition memory) explained 40 per cent of the variance, with better reasoning skills and letter-number sequencing associated with a shorter AB, and better visuo-spatial recognition memory associated with a longer AB. Conclusion: The positive beta weight in the model for visuo-spatial recognition memory may reflect that the ability to later recall a target depends on its depth of encoding. On the other hand, the negative betas in the regression model for verbal intelligence and processing speed indicate that AB duration may be a potentially useful measure of temporal rate of visual processing. Finally, the lack of any relationship between the AB and executive function performance measures used suggests that the mechanism of the AB is primarily confined to early sensory processing and lower level working memory