Related Experiment Video

Updated: Jun 28, 2026

Studying Food Reward and Motivation in Humans
12:09

Studying Food Reward and Motivation in Humans

Published on: March 19, 2014

Extrinsic rewards undermine altruistic tendencies in 20-month-olds

Felix Warneken1, Michael Tomasello

  • 1Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. warneken@eva.mpg.de

Developmental Psychology
|November 13, 2008
PubMed

Insights

Extrinsic rewards, like material items, decrease young children's helping behavior. Early helping is intrinsically motivated, and rewards can undermine this natural tendency.

Area of Science:

  • Developmental Psychology
  • Behavioral Economics

Background:

  • Early childhood development involves understanding prosocial behaviors like helping.
  • The motivation behind prosocial behavior in infants is a key area of research.
  • The impact of external incentives on intrinsic motivation is debated.

Purpose of the Study:

  • To investigate the effect of material rewards on the helping behavior of 20-month-old infants.
  • To examine whether extrinsic rewards influence the intrinsic motivation for helping in early childhood.

Main Methods:

  • Infants were divided into groups receiving either a material reward, social praise, or no reward.
  • Helping behavior was observed and measured during a subsequent test phase.
  • A controlled experimental design was employed to compare behavioral outcomes across groups.

Main Results:

  • Infants who received a material reward showed significantly less helping behavior compared to control groups.
  • Social praise did not diminish helping behavior, unlike material rewards.
  • The overjustification effect was observed, indicating reduced intrinsic motivation after material reward exposure.

Conclusions:

  • Very young children's helping behavior is intrinsically motivated.
  • Socialization practices using extrinsic rewards can negatively impact early prosocial tendencies.
  • Interventions aimed at fostering helping behavior should consider the potential downsides of material incentives.

More Related Videos

A Conflict Model of Reward-seeking Behavior in Male Rats06:11

A Conflict Model of Reward-seeking Behavior in Male Rats

Published on: February 20, 2019

Pavlovian Conditioned Approach Training in Rats06:57

Pavlovian Conditioned Approach Training in Rats

Published on: February 4, 2016

Related Concept Videos

Egoism and Altruism01:55

Egoism and Altruism

Voluntary behavior with the intent to help other people is called prosocial behavior. Why do people help other people? Is personal benefit such as feeling good about oneself the only reason people help one another?
Incentive Theory: Pull Theory of Motivation01:18

Incentive Theory: Pull Theory of Motivation

Incentive theory, or the "pull theory" of motivation, suggests that external rewards primarily drive behavior. Individuals are motivated to engage in activities when they anticipate a desirable outcome. This is why people often work hard for promotions or study intensively to achieve high grades. These incentives can be tangible, physical rewards such as money or promotions, or intangible, non-physical rewards like praise and social recognition.
The theory differentiates between intrinsic and...
Altruism01:03

Altruism

Altruistic behaviors are “unselfish” behaviors—those that help another individual at the expense of the individual carrying out the behavior. Despite the negative consequences for the altruistic animal, these behaviors are thought to have evolved for several reasons.
Timing and Consequences on Behavior01:08

Timing and Consequences on Behavior

In operant conditioning, the timing of reinforcement is crucial. For animals like rats and cats, immediate reinforcement (within a few seconds) is much more effective than delayed reinforcement. For example, a food reward for a rat needs to follow within 30 seconds of pressing a bar to be effective. 
Humans, however, can respond to delayed reinforcers. We often make decisions between immediate small rewards and delayed larger rewards. This ability to delay gratification is a significant factor...
Secondary Motives: Affiliation Motivation and Aggression Motivation01:21

Secondary Motives: Affiliation Motivation and Aggression Motivation

Affiliation motivation is the intrinsic desire to connect with others and belong to a social group, which plays a crucial role in forming and maintaining personal relationships. This type of motivation is essential for psychological well-being, as it provides individuals with a sense of community and support. An example of this is a student who joins a study group in order to feel a sense of connection. People with high affiliation motivation actively seek social approval, take satisfaction in...
Primary and Secondary Reinforcers01:23

Primary and Secondary Reinforcers

In psychology, reinforcement is a key concept in behavior modification. B.F. Skinner demonstrated this with his experiments involving rats in what is known as a Skinner box. The rats learned to press a lever to receive food, a primary reinforcer that fulfilled their innate need for nourishment.
Effective reinforcers for humans vary depending on the individual and the context. Primary reinforcers, such as food, water, sleep, shelter, and pleasure, have inherent value and satisfy basic biological...