Neurology Center

There are three basic schools of thought on the Israel / Palestine thing.

• Those evil Israelis are out to destroy Palestine, and the Palestinians are just fighting back.
• Those evil Palestinians are out to destroy Israel, and the Israelis are just fighting back.
• It's a cycle of violence, where both sides are fighting back against the other.
  

Which one you subscribe to depends mostly on where you were born. I'm not aware of many people who've changed their minds on this issue, perhaps because doing so would require a study of the last 2,500 years of history, religion and politics.

Wouldn't it be handy if science could provide an answer? According to the authors of a new paper in Proceedings of the National Academy of Science, the "cycle" school is right: both sides are fighting back against the other: Both sides retaliate in the Israeli-Palestinian conflict.

The authors (from Switzerland, Israel and the USA) took data on daily fatalities on both sides, and also of daily launches of Palestinian "Qassam" rockets at Israel. The data run from 2001, the start of the current round of unpleasantness, to late 2008, the Gaza War.

They looked to see whether the number of events that happened on a certain day predicted the number of events caused by the other side on the following days, i.e. whether a Palestinian death caused the Palestinians to retaliate by firing more rockets and killing more Israelis, and vice versa.

What happened? They found that both sides were more likely to launch attacks on the days following a death on their own side. The exception to this rule was that Israel did not noticeably retaliate against Qassam launches. This is perhaps because Qassams are so ineffective: out of 3,645 recorded launches, they killed 15 people.

These graphs show the number of "extra" actions on the days following a event, averaged over the whole 8 years, according to a statistical method called the Impulse Response Function. Note that the absolute size of the effects is larger for the Israeli retaliations (the Y axis is bigger); there were a total of 4,874 Palestinian fatalities and 1,062 Israeli fatalities

The authors then used another method called Vector Autoregression to discover more about the relationship. In theory, this method controls for the past history of actions by a given side, so that it reveals the number of actions independently caused by the opposing side.

the number of Qassams fired increases by 6% on the first day after a single killing of a Palestinian by Israel; the probability of any Qassams being fired increases by 11%; and the probability of any Israelis being killed by Palestinians increases by 10%. Conversely, 1 day after the killing of a single Israeli by Palestinians, the number of Palestinians killed by Israel increases by 9%, and the probability of any Palestinians being killed increases by 20%

....retaliation accounts for a larger fraction of Palestinian compared with Israeli aggression: in the levels specification, 10% of all Qassam rockets can be attributed to prior Israeli attacks on Palestinians, but only 4% of killings of Palestinians by Israel can be attributed to prior Palestinian attacks on Israel.... 6% of all days on which Palestinians attack Israel with rockets, and 5% of all days on which they attack by killing Israelis, can be attributed to retaliation; in contrast, this is true for only 2% of all days on which Israel kills Palestinians.

What are we to make of this? This is a good paper as far as it goes, and it casts doubt on earlier analyses finding that Israel is retaliating against Palestinians but not vice versa. However, the inherent problem with all of this research (beyond the fact that it's all based on correlations and can only indirectly imply causation), is that it focuses on individual acts of violence. The authors say, citing surveys, that

Over one half of Israelis and three quarters of Palestinians think the other side seeks to take over their land. When accounting for their own acts of aggression, Israelis often claim to be merely responding to Palestinian violence, and Palestinians often see themselves as simply reacting to Israeli violence.

But I don't think many Israelis would argue that the IDF only kills individual Palestinians as a reflex reaction to a particular attack. They're claiming that the whole conflict is a defensive one, that the Palestinians are the aggressors, but that doesn't rule out their taking the initiative on a tactical level e.g. in destroying Palestinian military capabilities before they have a chance to attack. And vice versa on the other side.

WW2 was a war of aggression by the Axis powers, but that doesn't mean that the Allies only killed Axis soldiers after they'd attacked a certain place. The Allies were on the offensive for the second half of the war, and eventually invaded the Axis's own homelands, but it was still a defensive war, because the Axis were responsible for it.

For Israel and for Palestine, the other guys are to blame for the whole thing. Who's right, if anyone, is fundamentally a historical, political and ethical question, that can't be answered by looking at day-to-day variations in who's shooting when.

Comment Policy: Please only comment if you've got something to say about this paper, or related research. Comments that are just making the case for or against Israel will get deleted.

Haushofer J, Biletzki A, & Kanwisher N (2010). Both sides retaliate in the Israeli-Palestinian conflict. Proceedings of the National Academy of Sciences of the United States of America PMID: 20921415