"Retain Your Knowledge: Decision Making and Hunger Does hunger improve strategic decision making? That is, if you are hungry are you more likely to make a favorable decision when the outcome of your decision is uncertain (as in business decisions)? To test this theory, researchers randomly divided 30 normal weight individuals into two groups. All subjects were asked to refrain from eating or drinking (except water) from 11 P.M. on the day prior to their 9 A.M. meeting. At 9 A.M., the subjects were randomly assigned to one of two groups. The subjects in Group 1 were fed breakfast while the subjects in Group 2 were not fed. All subjects were administered a computerized version of an exam that assesses complex decision making under uncertain conditions. The assessment consisted of subjects choosing cards from four decks marked A, B, C, and D. Cards in decks A and B had a point value of 100 while cards in decks C and D had point values of 50. However, deck A had penalty cards that deducted points between 150 and 300; deck B had one penalty card of 1250; deck C had penalty cards between 25 and 75 points; deck D had a single penalty card of 250 points. So, decks A and B had stiffer penalties over the long haul than decks C and D and in the long haul, decks C and D resolted in more points than decks A and B. In total, the subjects would select 100 cards. However, the response variable was the number of cards selected from decks C and D out of the last 60 cards selected. The thinking here is that after 40 card selections, the subjects would be aware of the advantage of decks C and D. The researchers administered a Barret Impulsivity Scale to be sure the two groups did not differ in terms of impolsivity (e.g., “I do things without thinking”). There was no difference in impulsivity, age, or body mass index between the two groups. Before the exam, subjects were asked to report their level of hunger and it was found that Group 2 was significantly more hungry than Group 1. After analysis of the data, it was determined that the mean number of advantageous cards (decks C and D) selected by the subjects in Group 2 was 33.36 cards while the mean was 25.86 for the subjects in Group 1. The researchers concluded that hunger improves advantageous decision making.
a. What type of experimental design is this?"

Verified step by step guidance

1. Identify the key features of the study design: participants were randomly assigned to two groups (fed breakfast vs. not fed), and the researchers controlled the conditions (fasting before the experiment).
2. Recognize that the independent variable (whether subjects were fed or not) is manipulated by the researchers, which is a hallmark of an experimental design.
3. Note that the random assignment of subjects to groups helps control for confounding variables, increasing the internal validity of the study.
4. Since the study compares outcomes (number of advantageous cards selected) between two groups under controlled conditions, it is a controlled experiment.
5. Therefore, classify this design as a randomized controlled experiment (or randomized controlled trial), where participants are randomly assigned to treatment and control groups to test the effect of hunger on decision making.

Key Concepts

Randomized Controlled Experiment

A randomized controlled experiment involves randomly assigning participants to different groups to test the effect of an intervention. This design helps control for confounding variables and allows causal inferences by comparing outcomes between treated and control groups. In this question, subjects were randomly assigned to either a fed or unfed group to test hunger's effect on decision making.

Independent and Dependent Variables

The independent variable is the factor manipulated by the researcher, while the dependent variable is the outcome measured. Here, hunger status (fed vs. unfed) is the independent variable, and the number of advantageous cards selected (from decks C and D) is the dependent variable, reflecting decision-making performance.

Control of Confounding Variables

Controlling confounding variables ensures that differences in outcomes are due to the treatment, not other factors. The researchers controlled for impulsivity, age, and BMI by measuring and confirming no group differences, strengthening the validity of the conclusion that hunger influenced decision making.