A Method for Manipulating Blood Glucose and Measuring Resulting Changes in Cognitive Accessibility of Target Stimuli

Summary

The authors introduce a method for manipulating blood glucose and measuring resulting changes in cognitive accessibility of target words using a lexical decision task.

Abstract

Much research in social psychology has investigated the impact of bodily energy need on cognition and decision-making. As such, blood glucose, the body's primary energy source, has been of special interest to researchers for years. Fluctuations in blood glucose have been linked to a variety of changes in cognitive and behavioral processes, such as self-control, political attitudes, and eating behavior. To help meet growing interest in the links between bodily energy need and these processes, this manuscript offers a simple methodology to experimentally manipulate blood glucose using a fasting procedure followed by administration of a sugar-sweetened, unsweetened, or artificially-sweetened beverage. This is followed by presentation of a method for measuring resulting changes in implicit cognition using a lexical decision-task. In this task, participants are asked to identify whether strings of letters are words or non-words and response latencies are recorded. Sample results from a recent publication are presented as an example of the applications for the experimental manipulation of blood glucose and the lexical decision task measures.

Introduction

Researchers in cognitive psychology and neuroscience have long studied the impact of blood glucose fluctuations on the brain, cognition, and behavior¹. For example, researchers have found that fluctuations in blood glucose predict differences in memory (verbal, digit span, working, and episodic)^1-5, attention^6,7, puzzle solving⁸, and performance on tasks of varying levels of cognitive demand^2,9,10. This research finds that increasing blood glucose enhances attention and memory, and that these effects are strongest when working on cognitively demanding tasks, and in those of older age^1,3.

Protocol

Ethics Statement: Procedures and incentives involving human subjects have been approved by the Institutional Review Board (IRB) at Texas Christian University.

1. Participant Inclusion Factors and Recruitment

1. Exclude people who have sugar sensitivities or any other health condition, like diabetes or other conditions that impair glucoregulation, and that would preclude them from being able to safely consume a sugar sweetened or artificially sweetened beverage. Exclude participants with a body mass index (BMI) over 30, as obesity is associated with energy dysregulation³¹.
   NOTE: If any of the following behavioral d....

Results

Participants

The above methods were implemented in a study run by Hill and colleagues²⁰ at a midsize, private university in the southern United States. The undergraduate population at the university provided the subject sample and participants received partial course credit as compensation for study participation. Using the exact methods outlined in the current manuscript protocol, the authors ran participants through.......

Discussion

This manuscript outlines a simple, inexpensive procedure for manipulating blood glucose, as well as a procedure for measuring resulting changes in the cognitive accessibility of target words and concepts. The above outlined methods can be applied to a wide range of research areas including social psychology, cognitive psychology, and nutrition sciences. Given that this method may be used by people in multiple research areas (some that do not typically use survey data), this section will present some tips on critical step.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Survey Building Software	Qualtrics	Qualtrics Research Suite	Alternative survey building softwares/applications include Survey Monkey, Google Forms, Media Lab, and Inquisit software.
Behavioral Task Software (for lexical decision task)	Inquisit	Inquisit 4 Lab (4.0.8.0)	Alternative behavioral task softwares/applications include Media Lab/Direct RT or programming the task into an internet browser using a programming language of your choice (such as java).
Batch File	Microsoft	Microsoft Notepad; Windows
Lexical Decision Task Template	Millisecond	Millisecond survey library, cited template author is linked on page	Can build a lexical decision task by hand in other behavioral task softwares.
Participant Scheduling and Compensation Software	SONA systems	SONA systems scheduling software	Appointments can be arranged manually, too.
Statistical Analysis Software	IBM	IBM SPSS Statistics Standard, 22	Alternate softwares include SAS and R.
Blood glucose manipulating beverege paradigm	Coca Cola	Sprite, Sprite Zero, Sparkling water	Can use any store brand sugary beverage, non calorically sweetened beverage, and sparkling water beverage, as long as beverages are not easily discernable from each other by sight.
Lancet	Assure	Assure Lanets 23 gauge	Many brands of testing lancets available both online and at local pharmacies.
Blood glucose testing meter	Bayer's	Breeze 2	Many brands of testing meters available both online and at local pharmacies.
Blood glucose testing strips	Bayer's	Breeze 2	Many brands of testing strips available both online and at local pharmacies, but they must be compatible with your chosen meter.
Nitrile exam gloves (400 count)	Kirkland	Kirkland Signature Nitrile Exam Gloves	Any medical grade exam glove that provides sufficient protection from blood exposure can be used.
Disinfecting wipes	Lysol	Lysol Disinfecting Wipes Lemon Scent	Any wipe that can kill off any bloodborne or contact born contaminants.