The overall goal of this procedure is to elicit children's naturalistic lie-telling behaviors in a deliberately designed laboratory setting. This method can help answer key questions in the field of children's social development, such as the emergence of children's lie-telling behavior or the relationship between lie-telling and children's mental state understanding. The main advantage of this technique is that it allows ecologically valid explorations of children's naturalistic lie-telling behaviors.

To begin, introduce the child and the parent to the laboratory environment and allow the child to sit at a child-sized table. After allowing the child to acclimate to the testing room, offer three attractive gifts for the child and instruct the child to select the most desirable one. Then inform the child that the selected gift is the prize for winning three rounds of the following guessing game.

Instruct the parent to say goodbye to the child. Then allow the parent to join an assistant in the neighboring room to observe the testing session behind a one-way mirror. Prior to playing the guessing game, place two hidden objects in opaque upside-down cups on grooved plates.

Then fill a third cup with some rice and position it upside-down on another grooved plate. Next, invite the child to play a guessing game. Present the first cup to the child and inform the child that there is an object hidden under the cup.

Then provide clues to help the child guess the identity of the hidden object. When the child correctly identifies the first object, congratulate them and repeat the guessing game with the second hidden object. After the second round, present the child with the cup containing the hidden rice and the child's chosen prize.

Then inform the child that they will only receive the prize if they correctly guess the identity of an object hidden under the cup. Have an assistant knock on the door at this exact moment. Before exiting the room, instruct the child not to lift the cup to peek at the hidden object.

Stand behind the one-way mirror to observe the child's behavior. When the child lifts the cup to peak at the object, the rice will spill onto the grooved plate. Then return to the room one minute after the child started to peek and ask the child if they lifted the cup to peek at the object.

When the child answers no, despite the physical evidence of the transgression, look at the spilled rice and ask yourself out loud, Why is this rice outside of the cup? Once more, ask the child if they lifted the cup to peek at the object and wait for them to respond. When the child continues to deny having lifted the cup to peek, ask the child how the rice spilled outside of the cup one last time and wait for the child to respond.

The cup flew up in the sky. Then tell the child that it was just a game and it is normal for children to peek and say they didn't peek during the game because the prize is very tempting. Give the child the promised gift at the end of the testing session regardless of their responses during the guessing game.

Then inform the parent that the guessing game protocol is specifically designed to elicit lying behavior in children. Finally, explain to the parent that peeking and lying behaviors reflect sophisticated cognitive and social development. In this protocol, participants ranging from three to six years old were tested with the guessing game and two trained coders examined their answers and explanations.

The participants were divided into four groups depending upon their answers and explanations, strategic liars, non-strategic liars, truth tellers, and non-peekers. Approximately half of the children peeked under the cup in the experimenter's absence. On average, peekers initiated peeking behavior within 30 seconds of the experimenter's departure.

The majority of the peekers lied about their transgression and older children were more likely to lie than younger children. Older children were also more likely than younger children to use strategic lies. While attempting this procedure, it is important to remember to play the guessing game and the lie-eliciting procedure naturally.

Following this procedure, other measures, such as inhibitor-control or false-belief tasks can be performed in order to answer additional questions, like what abilities are related with children's deception. After its development, this technique paved the way for researchers in developmental psychology to explore children's lie-telling behaviors in social interaction.