Sex differences in the cognitive effects of tobacco abstinence: a pilot study.

Despite significant research demonstrating the deleterious effects of tobacco abstinence on memory, and research showing substantial sex differences in nicotine withdrawal and memory processes, there has been scant work on how males and females might differ in the effects of tobacco abstinence on memory and cognition. Using a standard recognition memory task, we conducted a pilot study to examine how 24 hours of tobacco abstinence in moderate to heavy smokers would affect memory in males and females. Twenty-five moderate to heavy smokers were tested following a period of smoking normally and following 24 hours of tobacco abstinence. At each session, participants completed a recognition memory task in which items were studied under full- and divided-attention conditions (a standard manipulation of memory encoding) as well as tests of passive short-term and working memory (forward and backward digit span). Tobacco abstinence significantly reduced memory performance under full attention conditions for males but not for females. A significant main effect of smoking status in which abstinence significantly reduced performance, as well as a main effect of encoding condition (divided attention < full attention), were found. Our results demonstrate that there may be substantial sex differences in the cognitive effects of tobacco abstinence. While preliminary, the data suggest the need for further, more extensive study of how males and females differ during tobacco abstinence. Such information will inform the best strategies for tobacco cessation efforts.

Evidence that episodic memory impairment during tobacco abstinence is independent of attentional mechanisms.

Previous studies have demonstrated reductions in episodic memory during nicotine withdrawal. However, these studies have been unable to dissociate memory reductions from losses in attention associated with tobacco abstinence. In the present study, the authors sought to determine whether episodic memory reduction is a primary effect of nicotine withdrawal during tobacco abstinence. Heavy smokers were tested when smoking normally and following 24 hrs of abstinence. Participants were tested with a recognition memory task in which items were studied under full and divided attention conditions. Forward digit span and backward digit span were also included as control measures. Withdrawal was associated with a reduction in memory performance that was independent of attention at encoding. The authors conclude that impairment of episodic memory is a primary effect of nicotine withdrawal during tobacco abstinence. Further research is required to determine if this is associated with continued use of tobacco and cessation failures.

Effects of word frequency on individual-item and serial order retention: tests of the order-encoding view.

The order-encoding view of the word frequency effect proposes that low-frequency (LF) items attract more attention to the encoding of individual-item information than do high-frequency (HF) items, but at the expense of order encoding (DeLosh & McDaniel, 1996). When combined with the assumption that free recall of unrelated words is organized according to their original order of presentation, this view explains the finding that HF words are better recalled than LF words in pure lists but that, in mixed lists, recall is better for LF words. The present study confirmed that in mixed lists, order memory becomes equivalent for HF and LF words and that the predicted pattern of order memory and recall holds fo r incidental order-encoding conditions, for longerlists than those used inprevious experiments, and for lists with minimal interitem associativity. Moreover, recall from HF lists declined, but recall from LF lists improved, in related-word lists, relative to unrelated-word lists, reversing the usual pure-list free recall advantage for HF words. These results were uniquely predicted by the order-encoding account and favor this view over accessibility, interitem association, and cuing effectiveness explanations of the word frequency effect.