Murray A. Straus and Mallie J. Paschall
Family Research Laboratory, University of New Hampshire
Durham, NH 03824 603-862-2594 firstname.lastname@example.org
This research was prompted by studies showing that talking to children (including pre-speech children) is associated with an increase in neural connections in the brain and in cognitive performance (Blakeslee, 1997). Those findings led us to theorize that if parents avoid corporal punishment (such as slapping a child's hand or "spanking," i.e., slapping on the buttocks) they are more likely to engage in verbal methods of behavior control such as explaining to the child, and that the increased verbal interaction with the child will in turn enhance the child's cognitive ability.
This theory was tested on 960 children of mothers in the National Longitudinal Study of Youth. This sub-sample consists of the children who were age 1 to 4 in 1986 and for whom cognitiveability measures were available for 1986 and 1990. Corporal punishment was measured by whether the mother was observed hitting the child during the interview and by a question on frequency of spanking in the past week. A corporal punishment scale was created by summing the scores for 1986 and 1988. cognitiveability was measured in 1986 and 1990 by tests appropriate for the age of the child at the time of testing. The cognitive ability scores were standardized relative to other children within one month of the same age, setting the mean at 100 and the standard deviation at 15.
A multiple regression analysis controlled for mothers' age and edition, whether the father was present in the household, number of children in the family, mother's supportiveness and cognitive stimulation, ethnic group, and the child's age, gender,and birthweight. The results indicated that each increase of one point on the six interval corporal punishment scale was associated with an average decrease of .51 points on the measure of cognitiveability. A plot of the mean change in cognitiveability, adjusted for the control variables, showed an increase in cognitiveability from Time 1 to Time 2 for children who were not spanked in either of the two sample weeks, whereas the cognitiveability of children who experienced frequent spanking decreased. Because cognitiveability was measured relative to other children of the same age, the findings indicate that spanking is associated with falling behind the average rate of cognitive development, not an absolute decrease in cognitiveability.
We also found indirect support for the part of the theory which argues that one of the reasons for the higher cognitiveability of children who are spanked the least is because, in the absence of corporal punishment, parents use more verbal methods of control such as explaining to the child. We found that the less corporal punishment the mothers in this sample used, the higher their score on a measure of cognitive stimulation for the child.
Use of corporal punishment by parents has been decreasing in many countries. During this same period, scores on intelligence tests have been increasing worldwide (Neisser, 1997). This could be coincidental, but it is also possible that the trend away from use of corporal punishment is part of the explanation for the increases in IQ scores. If so, ending or reducing corporal punishment takes on high priority.
The 1979 Swedish no-spanking law provides an example of a non-punitive method of reducing corporal punishment. To date only five countries have followed the Swedish example, but there are indications that other countries, such as Canada and Germany, may also ban corporal punishment. Future research could test the hypothesis that countries that have gone so far as to enact legislation against corporal punishment experienced the largest average increase in cognitiveability.
Although American parents now use corporal punishment less frequently and for fewer years, the majority continue to spank and slap children (Straus & Stewart, 1998). In view of the continuing prevalence of corporal punishment, if the findings of this study are confirmed by other studies, media and educational programs that make clear the benefits of avoiding corporal punishment, could further reduce corporal punishment. A reduction in corporal punishment could have major benefits for children and society as a whole. These benefits are not limited to enhanced mental ability. Recent empirical research suggests that the benefits of reduced corporal punishment are likely to include less juvenile delinquency, less adult violence, less masochist sex, a greater probability of completing higher education, higher income, and lower rates of depression and alcohol abuse (Kaufman Kantor & Straus, 1994; Straus, 1994).