Caffeine, extraversion and working memory

Abstract

Research has shown that extraverts performing a working memory task benefit more from caffeine than do introverts. The present study aimed to replicate this and extend our knowledge by using a lower dose of caffeine (65 mg) and a range of tasks related to different components of working memory. In addition, tasks assessing psychomotor speed and the encoding of new information were included to determine whether caffeine-extraversion interactions were restricted to working memory tasks. A double-blind design was used, with 128 participants being randomly assigned to caffeinated or de-caffeinated coffee conditions. The results showed that caffeine interacted with extraversion in the predicted direction for serial recall and running memory tasks. Caffeine improved simple reaction time and the speed of encoding of new information, effects which were not modified by extraversion. These results suggest possible biological mechanisms underlying effects of caffeine on cognitive performance.

Benefits of Distraction

“…Thus the Yerkes-Dodson law in its original version (Yerkes & Dodson, 1908) is too simplistic (Hanoch & Vitouch, 2004), because the relationship between arousal and performance is much more complex than was initially assumed. In accordance with findings in previous studies (Campbell et al, 2011;Smillie & Gökçen, 2010;Smith, 2013), we concluded, first, that cognitive activation raises arousal levels just as both caffeine and vigorous exercise do, and, second, that extroverts outperform introverts, especially under high-arousal conditions and in tasks that have high cognitive demands or require a fast response rate. Our results suggest that extroverts can be very productive in a noisy and busy environment, whereas introverts may need a quiet working environment to be able to focus.…”

“…The authors suggested that, as the degree of extraversion became greater, higher levels of dopamine were available, giving extroverts the ability to be more responsive to necessary changes in dopamine activity in relation to some aspects of the task, such as difficulty. Furthermore, in the execution of working memory tasks, extroverts showed a greater benefit than introverts did from an intake of caffeine (Smillie & Gökçen, 2010;Smith, 2013), whereas introverts performed better in the low-arousal condition without caffeine (Smith, 2013).…”

Caffeine and Selective Adenosine Receptor Antagonists as New Therapeutic Tools for the Motivational Symptoms of Depression

“…Caffeine is typically consumed in order to increase alertness, arousal and energy ( Malinauskas et al, 2007 ). Its consumption has been related to changes in cognitive performance and mood in normal population ( Smith, 2013 ; Pasman et al, 2017 ). However, it enhances performance more in fatigued than well-rested subjects ( Lorist et al, 1994 ; Childs and de Wit, 2008 ).…”

Why is working memory performance unstable? A review of 21 factors

“…Using a double-blind placebo controlled design, Smillie and Gokcen (2010) found that 200mg of caffeine improved n-back performance for extroverts, but not introverts, on a high load n-back task. This experiment was replicated with a relatively low dose of caffeine, 65mg in a cup of coffee, resulting in greater WM improvement for extroverts compared to introverts ( Smith, 2013 ). Altogether, these studies support the hypothesis that dopamine plays an important role in WM performance and provide evidence for differences in WM processes between introverts and extroverts.…”