Question

For each of the statistical studies described indicate whether the study is an observational study or an experiment. Give a brief explanation for your choice. An article in USA Today (October 19,2010 ) describes a study of how young children learn. Sixty-four 18 -month-old toddlers participated in the study. The toddlers were allowed to play in a lab equipped with toys, which also had a robot hidden behind a screen. The article states: "After allowing the infants play time, the team removed the screen and let the children see the robot. In some tests, an adult talked to the robot and played with it. In others the adult ignored the robot. After the adult left the room, the robot beeped and then turned its head to look at a toy to the side of the infant. In cases where the adult had played with the robot, the infant was four times more likely to follow the robot's gaze to the toy."

Short answer

The statistical study described in the exercise is an Experiment because the researchers intentionally controlled variables such as the interaction between adult and robot, as well as the robot's actions, and then observed the effect on the toddlers' responses.

Step-by-step solution

Identify the Role of Researchers

In the study, the researchers allow the toddlers to play in a lab with toys and present a robot with a different set of actions. It means they are controlling the variables, deciding which toddlers see an adult interacting with the robot, and which ones see an adult ignoring it.

Identify the Manipulation of Variables

The researchers alter the environment by controlling the robot's activity and adult's interaction with it, then observe the toddler's reaction. This shows there is an intentional change in conditions.

Classify the Type of Study

Since researchers manipulate the variables and measure the effect, which in this case is the toddler's reaction to robot's gaze, this study falls under experimental studies. Experimental studies involve manipulation of one variable to determine if changes in one variable lead changes in another variable.

Key concepts

Observational Study

In an observational study, researchers collect data without interfering with the subjects' environment or behavior. They observe and record findings as they unfold naturally. Unlike experiments, they do not manipulate variables and therefore cannot establish causal relationships as confidently.

For instance, if we were to just observe the toddlers' interactions with toys and the robot without any induced conditions, that would constitute an observational study. Researchers would note how often, if at all, toddlers looked where the robot was looking, but wouldn't influence their behavior by introducing an adult into the scenario.

Manipulation of Variables

The manipulation of variables is a defining feature of experimental studies. Here, the researchers actively change one or more variables to observe the effect of these changes on other variables. In the toy and robot study, manipulation occurs when an adult either interacts with the robot or ignores it.

The toddlers' subsequent reaction to the robot's actions is observed to see how the manipulated variable, which is the presence and behavior of the adult, influenced the toddlers' gaze following behavior.

Control Group

A control group is pivotal in experimental research design. It's a baseline group that does not receive the experimental manipulation. This group helps researchers compare results and understand the effects of the manipulated variable.

In the context of our robot study, if some toddlers watched a robot without having seen any adult-robot interaction (assuming this scenario is common in their daily experience), that group of toddlers could be viewed as a control group against which to compare the behavior of toddlers who observed the adult playing with the robot.

Dependent and Independent Variables

An independent variable is the one that researchers manipulate, while the dependent variable is the outcome they are interested in measuring.

In the discussed study, the independent variable could be the adult's interaction with the robot (since this is manipulated). The dependent variable would be the toddler's likelihood of looking at the toy that the robot gazed at after beeping. This relationship demonstrates the effect of the former on the latter and allows researchers to make conclusions about cause and effect within the experiment.