The synchronicity of stock traders

In recent years, sociologists have produced a number of interesting works regarding the behavior of economic insiders. In a recent study published in the Proceedings of the National Academy of Sciences, the authors argue that stock traders have fairly synchronized behavior:

Sociologist Brian Uzzi of Northwestern University in Evanston, Illinois, and colleagues analyzed all trades taking place in a single firm of 66 employees over 2 years. As is usual in trading firms, the employees specialized in different markets—housing, autos, or health care, for example—so they had no obvious incentive to copy one another’s behavior. Each trader typically bought or sold stocks about 80 times a day, which the researchers allotted to second-long time windows.

A 7-hour working day is roughly 25,000 seconds, so the chance of one employee’s 80 trades randomly synchronizing with any of his colleague’s is small. Yet Uzzi’s group found that up to 60% of all employees were trading in sync at any one second. What’s more, the individual employees tended to make more money during these harmonious bursts…

This is interesting information in itself: there are common patterns to behaviors in which we might typically assume that traders act on their own. But perhaps the more interesting aspect of all of this is why these trader’s actions are so synchronized. Here is what the authors suggest:

They believe the synchronized behavior is simply a general indicator that the market is ripe for safe trading. Although each individual trader has a short-sighted view of his or her specialist market, the traders’ collective monitoring of events in the outside world means that, at some point—indeed, at 1 second—group instinct prompts many of them to buy or sell together. The researchers found that instant messaging among traders spiraled at times of synchronicity, which seems to support this view. Trading out of sync, Uzzi says, would mean the trader misses out on the time when the market information was optimal for a return.

So even with specialized tasks, these traders are then monitoring broader conditions and responding to group behavior. This seems to fit with other sociological research that suggests that economic decisions that often get chalked up to things like rationality or intuition are influenced by social factors.

There is an intriguing implication as well:

Uzzi thinks trading firms could capitalize on the phenomenon by giving their employees more money to trade when they are in sync. But he warns that the traders themselves must never be told about the decision. “It is well-known that once people become self-conscious of their own behavior, their behavior changes,” he says.

So will behaviors (and outcomes) change if this article becomes common knowledge amongst traders?