Research Highlights


Designing Better Energy Metrics for Consumers

Access to the original article

Larrick, R. P., Soll, J. B., & Keeney, R. L. (2015). Designing better energy metrics for consumers. Behavioral Science and Policy, 1, 63-75. (link to pdf)  email

When Power Makes Others Speechless: The Negative Impact of Leader Power on Team Performance

Access to the original article

Tost, L. P., Gino, F. , & Larrick, R. P. (2013). When power makes others speechless:  The negative impact of leader power on team performance. Academy of Management Journal, 56, 1465-1486. email

Research summaries


Political Ideology Affects Energy Efficiency Attitudes and Choices

Access to the original article

Gromet, D. M., Kunreuther, H., & Larrick, R. P. (2013). Political ideology affects energy-efficiency attitudes and choices.   Proceedings of the National Academy of Sciences, 110, 9314-9319.  email

° Additional commentary by Dietz, Leshko, and McCright.

Research summaries


Temper, Temperature, and Temptation: Heat-Related Retaliation in Baseball

Access to the original article

Larrick, R. P., Timmerman, T. A., & Carton, A. M., & Abrevaya, J. (2011). Temper, temperature, and temptation: Heat-related retaliation in baseball. Psychological Science22, 423-428. DOI available from author

Research summaries

Research Background

This summary provides a brief overview of the research–it is not the published article in Psychological Science. Please click on the links above to go to the published article.

How Common is Being Hit By A Pitch in Major League Baseball?

The probability of a batter being hit by a pitch in a Major League Baseball (MLB) game is low.  Each time a batter steps to the plate, there is a little under a 1% chance that he will be hit by a pitch.

Although the chances of being hit by a pitch are low in any given plate appearance, there are a lot of plate appearances in a season. This yields a large number of hit batters every year.

Specifically, there are about 80 plate appearances in an average MLB game, and about 2,400 games played per year, yielding roughly 190,000 plate appearances during a major league season.

As a result, in recent seasons, about 1,550 batters have been hit by a pitch during the season.

How Is Temperature Related to the Number of Batters Hit by a Pitch?

For every increase of one degree of temperature (F), the number of batters hit per game increases by .002.  The average game is played at roughly 75 degrees.  Last season about 1,550 batters were hit by a pitch.

To illustrate the relationship between temperature and the number of hit batters, it is useful to consider, statistically, how the number of hit batters might change if all games were played at very cool temperatures, such as 55 degrees, or at very hot temperatures, such as 95 degrees:

If all games were played at 55 degrees, the number of hit batters would be expected to drop by roughly 100 batters (20 x .002 x 2,430), to about 1,450batters.

If all games were played at 95 degrees, the number of hit batters would be expected to increase by roughly 100 batters (20 x .002 x 2,430), to about1,650 batters.

Why Are Batters Hit by Pitches?

Most batters are hit by accident. It is costly to hit an opposing batter because the batter is awarded first base. This prolongs an inning and makes it more likely that the opposing team will score.

Baseball is full of lore, however, about when pitchers should intentionally hit a batter with a pitch. There is a long-standing tradition of retributive justice in baseball that states that, if a teammate is hit by a pitch, a player on the opposing team must be hit in return (Turbow & Duca, 2010). This Hammurabi code of a “batter for a batter” (Bissinger, 2005, p. 112) serves both to restore justice and to deter future harm. Previous research has found empirical support for retaliatory behavior in baseball (Timmerman, 2007).

Why Is Temperature Related to the Number of Batters Hit by a Pitch?

Research in social psychology has shown that aggression increases with temperature(see research by Craig Anderson for an overview). These patterns have been found in field tests of violent crime patterns and in controlled laboratory settings where people are randomly assigned to levels of temperature.  Laboratory research has shown that the discomfort caused by higher temperatures increases anger and negative affect, which makes aggression more likely.

In the paper “Temper, Temperature, and Temptation:  Heat-Related Retaliation in Baseball,” (Larrick, Timmerman, Carton, & Abrevaya, Psychological Science, 2011), we propose that hitting a batter in baseball is also an act of aggression.  We argue that heat changes how pitchers respond when their own teammates have been hit by a pitch.  The same ambiguous act—a hit teammate—is interpreted as a more hostile action at hot temperatures; and, at hot temperatures, pitchers have lower inhibitions for being aggressive.  We propose that the rule of a “batter for a batter” is enforced more at hot temperatures than at cold temperatures.  Heat increases retaliation.

We analyzed 57,293 MLB games played between 1952 and 2009 (which had 4,566,468 plate appearances).  We used logistic regression to predict the probability that a pitcher would hit a batter with a pitch in a given plate appearance as a function of temperature and the number of pitcher’s teammates who had been hit earlier in the game.   In our regression analysis, we controlled for variables that may be correlated with the likelihood of hitting a batter, such as year, attendance, the use of a DH, and the inning, as well as variables that proxy for pitcher inaccuracy, such as walks, wild pitchers, and errors (to address a “sweaty hand” explanation).

The following figure summarizes the results from the regression (used with permission from Psychological Science):

There are about 190,000 plate appearances during the MLB season. In a typical plate appearance, batters have less than a 1% chance of being hit by a pitch (which is .01 when stated as a probability). This figure shows how the probability that a pitcher will hit an opposing batter changes as a function of temperature and hit teammates.

When no teammates have been hit, the likelihood that a pitcher will hit a batter is low for all temperatures (around .7%).

Temperature is more strongly related to a pitcher hitting a batter if a teammate has been hit.

If one teammate has been hit, there is a .7% chance that a pitcher will hit a batter during games played below 60 degrees; this likelihood increases to .9% in games played above 90 degrees.

If two teammates have been hit, the likelihood of hitting a batter climbs from .7% below 60 degrees to more than 1% above 90 degrees.

The table below gives the predicted percentages that a batter will be hit by a pitch during a plate appearance for games played below 60 degrees and for games played at 90 degrees or above:


Number of Hit Teammates

<60 degrees

90+ degrees










3 or more




Consider 1,000 plate appearances in which two of a pitcher’s teammates have been hit by a pitch earlier in the game. If the temperature is below 60, we’d expect the pitchers to hit 7.4 opposing batters with a pitch; if the temperature is above 90, we’d expect pitchers to hit 10.5 opposing batters with a pitch. Three more batters are expected to be hit as a result of the increase in temperature.


The MPG Illusion

Original article (free) and online supplement

Larrick, R. P., & Soll, J. B. (2008). The MPG illusionScience, 320, 1593-1594. (subscription free)

Here is the standard subscription-only link to the articleSupporting Online Materialspublished by Science can be found here (with additional examples, descriptions of GPM, and more on research methods and results). This requires no subscription.

Brief summaries of the MPG illusion argument press releaseQuizVideo, and Science podcast

GPM calculator

We provide a calculator that converts MPG to GPM at this website. The calculator also allows you to compare different levels of MPG to see gas and cost savings.

Additional tools for converting MPG to gallons per mile (GPM) can be found here, including printable tables and excel-based calculators.

More background on the MPG Illusion and the use of “GPM”

See this page


The Small Pie Bias in Negotiation 

Link to original aticle

Larrick, R. P., & Wu, G. (2007). Claiming a large slice of a small pie: Asymmetric disconfirmation in negotiation. Journal of Personality and Social Psychology, 93, 212-233Press Release OVID DOI available from author

Research summaries

Duke press release

Article in University of Chicago’s “Capital Ideas”

Harvard Program on NegotiationPrevention MagazineLA TimesBusinessweekUS NewsTheStreet.ComRaleigh News & Observer


Articles for General Outlets


Raising the bar on goals – Chicago GSB Magazine

Cash for clunkers? Do the math before trading – Atlanta Journal Constitution

You know more than you think – Mind Matters