Comparison of explicit vs. implicit measurements in predicting food purchases

In this study, we aimed to investigate the relation between consumer purchases of three branded blueberry flavored quarks and respective responses of the same consumers to these products using 1) traditional explicit consumer surveys measuring verbalized impressions, 2) novel explicit pictorial emoji scores and 3) implicit behavioral responses produced during an approach-avoidance task (AAT). Explicit measures (n=134) were collected before product tasting (expectation condition) during an online survey, and after product tasting (perception condition) during a Central Location Test (CLT). Implicit measures were collected with a subset of 56 randomly selected subjects during the CLT. These included electroencephalographic (EEG) measures, joystick response speed and pupil size responses. During one month following the CLT, respondents registered their purchases via an online diary. Bivariate correlations indicated that explicit scores correlate better with product purchase amounts in the perception condition than in the expectation condition. Furthermore, verbalized ratings correlated better with product purchase amounts than pictorial emoji scores. Of the implicit responses, EEG responses produced the strongest correlations with purchase behavior, similar to those observed for verbalized explicit ratings in the expectation condition. Multiple linear regression modelling indicated that the best-fitting model consisted of an emoji score, purchase intention score, pleasantness score, brand relationship score, and implicit joystick response speed. Overall, purchase behavior was associated stronger with explicit responses than with implicit responses. Yet, the prominent role of implicit joystick response speed in the multivariate regression model suggests its unique contribution to the understanding of purchase behavior.Peer reviewe

Failure of sucrose replacement with the non-nutritive sweetener erythritol to alter GLP-1 or PYY release or test meal size in lean or obese people.

There is considerable interest in the effect of foods containing high intensity sweeteners on satiation. However, less is known about low-calorie bulk sweeteners such as erythritol. In this randomized three-way crossover study, we studied 10 lean and 10 obese volunteers who consumed three test meals on separate occasions: (a) control sucrose meal; (b) isovolumic meal with partial replacement of sucrose by erythritol; (c) isocaloric meal which contained more erythritol but equivalent calories to the control meal. We measured gut hormone levels, hunger and satiety scores, ad libitum food intake, sucrose preference and intake after the manipulations. There was a greater post-prandial excursion in glucose and insulin levels after sucrose than after the erythritol meals. There was no difference in GLP-1/PYY levels or subsequent energy intake and sucrose preference between sucrose control and isovolumic erythritol meals. In lean (but not obese) participants, hunger decreased to a greater extent after the isocaloric erythritol meal compared to the control meal (p = 0.003) reflecting the larger volume of this meal. Replacing sucrose with erythritol leads to comparable hunger and satiety scores, GLP-1 and PYY levels, and subsequent sucrose preference and intake.Wellcome Trust, National Institute for Health Research Cambridge Biomedical Research Centre, Bernard Wolfe Health Neuroscience Fund, Swiss National Science Foundation (Grant IDs: PBLAP3-145870, P3SMP3-155318), NeuroFAST consortium, European Union's Seventh Framework Programme (FP7/ 2007e2013) Grant ID: 245009), Cargill, Sas van Gent, The NetherlandsThis is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.appet.2016.09.00