For most followers of football, the answer will seem obvious: a hell of a lot. Yet I would wager this is an intuitive answer, not an empirical one.
To demonstrate, take moment to do some introspection and ask yourself why you think player psychology matters in the context of a football match.
Here, I’ll start.
The intuitive part of me thinks player psychology matters because a less confident player won’t play as well. They will be more nervous, less determined to either take risks or push on to that next level of ability. They will be stuck in their heads. They will dwell on small mistakes and play scared. It’s for this reason that a lack of confidence across an entire team would therefore be a total disaster. Moreover, a team that is at odds with each other or is divided along factional lines won’t have confidence in their team-mates, and will negatively affect their play. Or a team with egotistical players will be less able to play well together.
I would also expect the converse to be true as well. It’s my guess that a confident player might play above their innate level of talent. A determined player might be less nervous, more eager to attempt something audacious that could change a game.
I’m not alone in these intuitive beliefs. In fact, they’re so ingrained in both fans and media that we rarely question anyone who wonders in print if a team has the ‘experience’ or ‘mettle’ to play confidently against another opponent, even an opponent that is roughly equal in talent.
Yet this idea of player psychology raises several interesting questions. If a team that isn’t confident scores a lucky goal, does their confidence suddenly improve, or is it a more gradual process? Does the confidence boost help improve the baseline ability of the whole team? Does the goal scored conversely affect the confidence of the other team? And in both cases, does this ability boost come with an expiry date? How long generally does this confidence boost last?
More importantly, does this confidence boost/drop improve/worsen the innate talent of both sides? Does it depend on the scoreline? An equalizing goal might have more of a bigger confidence effect than a goal-scored at 4-0, for example. Are there such things as confidence feedback loops? As in, do more positive events—chances created, possession maintained, etc—lead to more positive events?
Or are footballers naturally confident? We know a lot of footballers carry major egos; perhaps that’s a necessary component for the job. Which would also mean that, if you lose confidence, you can’t play at the elite level anymore. And if you temporarily lost this confidence, your ability would temporarily suffer too.
Do extraneous variables affect confidence? Did Roberto Mancini’s unfamiliar 3-5-2 against Ajax for example throw off Manchester City’s self-belief? Do injuries and fitness levels affect confidence?
And isn’t it also possible that over-confident players would put too much stock in their ability and make mistakes from complacency? Or that less-confident, more self-critical players would be more alert and therefore make fewer mistakes? I know from my experience as a musician for example that some of the best auditions I’ve done have been when I’ve been the least confident, even nervous. But then again I’ve also sung poorly in those situations. So which is it?
These questions aren’t facetious, nor are they easily answered. For one, you would need to isolate for innate talent, luck, and confidence, and how they interrelate. This is rather important, because there is some evidence luck plays a major—if non-discrete—role in football, particularly as goals are relatively rare occurrences. Yet as it stands, the actual empirical evidence isn’t on the side of the psychology boosters—see both clutch and the hot hand fallacy.
All I am doing here is pointing out the answer isn’t as obvious as your intuition might lead you to believe. As ever, the onus of proof in these situations rests with those who make strong intuitive claims that either psychology doesn’t matter in football, or that it matters quite a bit. It’s safe to say most of us reside in the latter side of this divide. The Daily Mail for example dedicated an entire news column to whether David Luiz and Frank Lampard are friends again after a little on-field row in the Europa League.
That might strike you as ridiculous, but if player confidence and psychology is a big deal, the Mail is right to focus on whether Chelsea team-mates are getting along okay. While difficult, it would help for someone to concoct a study to determine whether psychology has an effect on team field sports and individual performances, so we can put this little bugbear to sleep.