Paul Hewlett

Correlates of daily caffeine consumption

A study of 376 young British adults showed that estimated daily caffeine consumption increased with age, and was associated with smoking and greater alcohol consumption. Non-consumers of caffeine avoided tea and coffee (even the de-caffeinated form). Level of caffeine consumption was not associated with impulsivity, sociability, extraversion or trait anxiety.

Grazing, cognitive performance and mood

Two experiments were carried out to examine how spreading food intake between either two or four occasions would affect mood and cognition. The first experiment used 96 participants in a between subject design where participants received either two milkshakes at 09:00 and 13:00 or four (half nutrient content but same volume) milkshakes at 09:00, 11:00, 13:00 and 15:00. The results showed that verbal reasoning accuracy improved in the four-milkshake condition. The second experiment used 24 participants in a cross-over design. The breakfast and lunch were halved in one condition and not in the other so participants either ate breakfast and lunch, or four meals at the same times as experiment 1. Verbal reasoning accuracy was improved by spreading the intake over four meals such that errors were reduced by between 30 and 40%. Speed was also increased in a five-item (but not one-item) search task. Further research is now necessary to uncover the mechanisms that underlie these effects.

An Investigation of the Acute Effects of Oligofructose-Enriched Inulin on Subjective Wellbeing, Mood and Cognitive Performance

Inulin is a natural food component found in many plants that are part of the human diet (e.g., leeks, onions, wheat, garlic, chicory and artichokes). It is added to many foods and is used to increase dietary fibre, replace fats or carbohydrates, and as a prebiotic (a stimulant of beneficial bacteria in the colon). Oligofructose, which is also present in these foods, produces similar effects and most research has used a combination of these products. A previous study (Smith, 2005) investigated the effects of regular consumption of oligofructose-enriched inulin on wellbeing, mood, and cognitive performance in humans. The results showed that oligofructose-enriched inulin had no negative effects but that it did not improve wellbeing, mood, or performance. The aim of the present study was to examine the acute effects of oligofructose-enriched inulin (5 g) over a 4 h period during which the participants remained in the laboratory. A double blind placebo (maltodextrin) controlled study (N = 47) was carried out with the order of conditions being counterbalanced and the two sessions a week apart. On each test day mood and cognitive performance were assessed at baseline (at 8:00) and then following inulin or placebo (at 11:00). Prior to the second test session (at 10:30) participants completed a questionnaire assessing their physical symptoms and mental health during the test morning. The inulin and placebo were provided in powder form in 5 g sachets. Volunteers consumed one sachet in decaffeinated tea or decaffeinated coffee with breakfast (9:00). Questionnaire results showed that on the day that the inulin was consumed, participants felt happier, had less indigestion and were less hungry than when they consumed the placebo. As for performance and mood tasks, the most consistent effects were on the episodic memory tasks where consumption of inulin was associated with greater accuracy on a recognition memory task, and improved recall performance (immediate and delayed). Further research is required to identify the mechanisms that underlie this effect with glucose metabolism being one candidate.

Tea, coffee and associated lifestyle factors

Purpose – The aim of this paper is to determine lifestyle factors associated with different drink choices as past research has suggested some differences.Design/methodology/approach – Caffeinated tea and coffee consuming habits in a South Wales sample were investigated by postal questionnaire. Multiple regression was used to determine odds ratios for demographic, health and lifestyle factors associated with drink patterns. There were 7,979 questionnaire respondents, 58 per cent of whom were female. Their mean age was 45.61 years (SD =18.00, range =16‐97).Findings – Caffeinated tea/coffee consumption was associated with both alcohol and smoking behaviours. The results also suggested that non‐consumers of caffeinated tea or coffee were not a homogeneous group, as different demographic and lifestyle profiles were identified for: those that did not drink tea or coffee at all; and those that drank only decaffeinated tea or coffee.Research limitations/implications – Future caffeine research may need to consider...

External validity and anchoring heuristics: application of DUNDRUM-1 to secure service gatekeeping in South Wales

Aims and method Structured clinical judgement tools provide scope for the standardisation of forensic service gatekeeping and also allow identification of heuristics in this decision process. The DUNDRUM-1 triage tool was completed retrospectively for 121 first-time referrals to forensic services in South Wales. Fifty were admitted to medium security, 49 to low security and 22 remained in open conditions. Results DUNDRUM-1 total scores differed appropriately between different levels of security. However, regression revealed heuristic anchoring on the ‘legal process’ and ‘immediacy of risk due to mental disorder’ items. Clinical implications Patient placement was broadly aligned with DUNDRUM-1 recommendations. However, not all triage items informed gatekeeping decisions. It remains to be seen whether decisions anchored in this way are effective. Declaration of interest Dr Mark Freestone gave permission for AUC values from Freestone et al. (2015) to be presented here for comparison.

Contextual representation may mediate sex differences in heterosexual attraction

Background Heterosexual men and women differ in their sensitivity to cues indicating material status. This dissociation has been explained by appealing to sexual selection processes that encourage women to evaluate men on the basis of their material status but could perhaps be explained by sex differences in contextual attention, or, associative representations. Method In Experiment 1, heterosexual women rated the attractiveness of an opposite sex model in 4 conditions; (1) attractive context, (2) attractive context with implied ownership, (3) unattractive context, and (4) unattractive context with ownership implied. A second experiment used a fictitious stockbroker learning task (with both men and women) in 2 biconditional discriminations to measure contextual attention (stage 1) and then to explore the structure of contextual representation (stage 2) using a transfer of occasion setting test. Results In Experiment 1, females increased ratings in attractive contexts, both when context ownership was impli...