I found this article in the NY Times which touches on the age of reason, and explains the difference between that at the age of 7, and (say) 13, and touches on Catholic Christianity, Judaism and Islam:
query.nytimes.com/gst/fullpage.html?sec=health&res=9A02E4DC1E3AF935A2575BC0A96E958260&n=Top%2FReference%2FTimes%20Topics%2FPeople%2FC%2FColes%2C%20Robert
I've picked out the relevant parts:
"AT the age of 7, a child is considered by the Roman Catholic Church to have reached the 'age of reason' and is entitled to receive communion. Some evangelical churches hold that a child of 7 can make an independent spiritual choice. In Judaism and Islam, a boy of 7 is expected to begin his religious studies and participate, to some degree, in adult rituals like fasting and praying. Freud believed the super ego, or the conscience, develops by age 4 or 5. "
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"Both Judaism and Islam, for example, set the age of majority, when children are liable for their actions, at 13 for boys and 12 for girls. 'It's the age of full responsibility and therefore full liability,' said David Kraemer, a professor at the Jewish Theological Seminary. Younger children are considered to have the impulse to do good and evil, he added, 'but not the reason to control the impulse.'
One rabbinic teaching goes further. While rabbinical courts consider a 13-year-old liable for his actions, in the court of heaven the age of majority is 20. 'It was a recognition that the teen-age years were very tumultuous and that, although they are full-grown and can do damage, God recognizes that they can't really be held responsible,' Dr. Kraemer said.
Islam, too, holds that a prepubescent child is not 'fully in control of his senses and doesn't have the power of reasoning to really make an informed judgment,' said Jamal Badawi, a Muslim scholar and chairman of the Islamic Information Foundation in Halifax, Nova Scotia. "
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"Since the days of Pope Pius X nearly a century ago, the Catholic Church has attributed to children of 7 the capacity to understand the consequences of their actions. That is a prerequisite for their First Communion, when they are first given a wafer in the sacrament of the Eucharist. But strict doctrine has given way to pragmatism. 'It all depends on the context,' said the Rev. Richard McCormick, a theologian at the University of Notre Dame. 'One of the criteria used in regard to the Eucharist is the ability to understand, in some very, very primordial sense, the difference between just plain bread and this bread that is really Jesus. As we all grow older, we understand and penetrate that a bit more.'
But children who may be old enough to take communion, he added, are not necessarily thought of as capable of understanding the nature of sin as a break with God. 'It's the conviction of virtually all people that children of that age are incapable of serious sin,' Father McCormick said. "
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"Reason, then, is not really the issue with a child of 7 or 8. 'It's not like a 4-year-old who happens to pull a trigger on a gun and doesn't understand that it kills, or doesn't understand what killing is about altogether, or what death is about,' said Moshe Halbertal, a professor of Jewish thought at Hebrew University in Jerusalem. 'Here, at 7 or 8 or 9, they understand. We don't attribute to them responsibility, but we do attribute to them understanding.'"