The Misconception of Weather's Influence on Cricket Ball Swing

After the thrilling 2015 Ashes series, which resulted in England's 3-2 victory over Australia, the two teams are scheduled to face each other again in a series of one-day matches, assuming the weather allows. The summer in the UK has been characterised by cloudy and humid conditions, and according to popular belief, this might have had an impact on the games.

During the last Test Match at the Oval, England's captain Alastair Cook made an unusual decision by choosing to field first after winning the coin toss. As a result, the Australian team managed to accumulate nearly 500 runs in their initial innings, leading to England's defeat. Surprisingly, despite the decision backfiring dramatically, no commentator questioned Cook's judgment. This is because many people believe that in cloudy and humid weather, swing bowling, which involves the ball curving in the air before reaching the ground, becomes more advantageous.

At the start of the Oval Test Match, experts in both television and the press were discussing how the prevailing conditions were advantageous for the bowlers. In an interview with Channel 5, Alastair Cook himself explicitly acknowledged the influence of the overcast conditions as a contributing factor in his choice to field first.

Weather’s impact

What is the origin of the widespread belief in the influence of weather conditions? Part of it stems from notable stories like that of Australian cricketer Bob Massie, who achieved remarkable success by taking 16 wickets during his Test Match debut at Lords in what was described as "perfect" weather with heavy air and cloudy skies. However, is there any systematic evidence to support this notion beyond compelling anecdotes?

Interestingly, a significant amount of scientific evidence exists that draws upon aerodynamic experiments, often conducted in wind tunnels with varying atmospheric conditions. The findings consistently fail to support the idea that humid and overcast conditions have an impact on the amount of swing the cricket ball experiences.

The earliest scientific study on cricket ball swing was published as far back as 1955, and subsequent research has been periodically reported in mainstream media. It is reasonable to assume that the increasingly data-driven and professional cricket community is aware of this evidence. So, what explains the persistence of this thoroughly discredited theory?

Perceptions can be misleading 

Some individuals may lack sufficient information or understanding, or they may be influenced by false beliefs, which could contribute to their misconceptions. The notion that humid air is denser than dry air appears to provide a sensible explanation for the phenomenon, but it is actually counterintuitive as humid air is less dense than dry air.

An increasing body of evidence on "motivated cognition" explains why people may not adjust their opinions even when presented with clear scientific evidence. Motivated cognition suggests that individuals subconsciously process information in a way that aligns with their goals or preferences, leading them to draw conclusions that suit their desired outcomes.

Studies on motivated cognition have demonstrated how individuals with different ideologies can reach disparate conclusions on contentious scientific matters, such as global warming or vaccination, despite being presented with the same information.

People may want to believe that cloudy days are better for swing bowling because it is a widely accepted belief within the cricket community. Challenging this belief could lead to a loss of credibility within one's social group or in-group.

To illustrate this point, let's imagine a scenario where Alastair Cook, a well-known cricketer, chose to bat first on a cloudy and humid day at the Oval, resulting in England losing the match. In such cases, motivated cognition would suggest that individuals would engage in cognitive processes to preserve their initial belief. They may come up with ad hoc explanations to justify why the expected conditions did not lead to the anticipated outcome. For example, during the final Ashes test match, commentators might suggest that the bowlers didn't execute their strategy correctly on the first morning or that the Australian batsmen performed exceptionally well, neutralising the swing.

Interestingly, individuals with extensive cricket expertise are more likely to be convinced by these ad hoc rationalisations. Their deep knowledge of other aspects of the game allows them to find supporting reasons that align with their initial belief, further reinforcing their conviction and potentially persuading others as well.

Other interpretations 

Psychological studies examining the persistence of misinformation indicate that correcting false beliefs is challenging unless a plausible explanation is provided to replace the erroneous one. The media has largely neglected to address this issue, leaving those who are captivated by the prevailing narrative without any compelling alternatives. However, several hypotheses are highly feasible and could be put forth as alternative explanations.

The most apparent hypothesis is that if a bowler believes that overcast conditions are conducive to swing, they will ensure that they bowl in a manner that maximises swing when such conditions are present. This is exactly what Bob Massie conveyed during a radio interview following his remarkable performance at Lords in 1972. He stated, "Once I woke up and looked out of the window and saw the greyness there, I knew it was going to be a day that if I, you know, bowled fairly well, I should get wickets because it was one of those tailor-made days for swing bowling."

Another possibility is that, with the belief that the conditions will favour swing bowling, selectors are more likely to include swing bowlers in the final team before a match, and captains will then deploy this type of bowler more frequently during periods of play when conditions appear to be favourable.

Can anything be clarified at all?

However, isn't it premature to make such conclusions? What empirical evidence do we have that demonstrates an increased occurrence of swing under these conditions, regardless of the reasons behind it? To the best of my understanding, there is no such evidence available. The only support for this claim comes from compelling anecdotes mentioned earlier and the unwavering conviction of players and observers that the phenomenon is real. So, is it possible that there is no observable correlation between weather and swing, and instead, our perceptions are influenced by psychological illusions?

Renowned psychologist Daniel Kahneman, who received a Nobel Prize, along with his colleague Amos Tversky, demonstrated that human thinking regarding probability and decision-making based on evidence is prone to biases, rendering us unreliable as intuitive scientists. Notably, vivid and memorable examples like Massie's test match are susceptible to confirmation bias, where we actively seek or recall instances that align with our preexisting beliefs while disregarding contradictory information. These two extensively studied cognitive biases suggest that we are more inclined to remember occasions when the ball swung significantly under cloudy conditions rather than when it exhibited the same behaviour under bright sunshine.