An anatomy of knowledge issues

Ric SimsIntegrating ToK across the Diploma

CurriculumNairobi October 2011

TerrorC-vitamin deficiency could lead to brain damage• (UNT – 2009)

Warning for acryl amide in coffee• (DN – 2002)

Hope (?)Coffee cures almost everything.• (The independent – 2009)

Diet control prolongs life• (Aftonbladet – 2009)

ResultMedia’s diet advice affects Swede’s food habits.•(Expressen – 2008)

Headline?Smoking is an inherited habit – if your parents smoked you are twice as likely to smoke yourself• (Sims weekly 2010)

Is the tendency to smoke inherited?If parents are smokers does this increase the

likelihood that the children become smokers?

Knowledge issues - observationLanguage: how exactly do we define

’smoker’? Once smoked, always smoked, sometimes smoked, 10 a day, 20 a day, 40 a day, only in the evenings? (this is more properly about concepts). Is it sufficient for the definition that just one parent smoked?

How do we extract information from the (messy) real world? Questionnaire? Who do we question (parents or children)? Reliability issues, wording of questionnaire (and so on)

Knowledge issues 2 - representationParents/children

smokers Non-smokers total

smokers 30 70 100Non-smokers 40 360 400total 70 430 500

Knowledge issues of manipulationIf parents smoking habits did not make a

difference we would expect that the proportion of smokers would be the same in both groups (those with smoking parents and those without)

(subtlety here: we assume an hypothesis of no effect and try to disprove it – cf. Popper and falsification)

This proportion is 70/430 = 16.3%

Expected distributionParent/children

smokers Non-smokers total

smokers 16 84 100Non-smokers 65 335 400total 81 419 500

Parents/children

smokers Non-smokers total

smokers 30 70 100Non-smokers 40 360 400total 70 430 500

Actual distribution

Model: Chi squaredGiven some basic technical assumptions

about the base population what is the probability that the observed distribution was achieved by chance?

First we decide on a significance levelWe calculate:

chi2 = sum of (observed – expected)**2/expected

In this case let us choose 5% significance level (i.e. We shall accept results which could be arrived at randomly from a uniform distribution with probability of 5% or less)

Chi squaredChi2 = 21. 3 for our resultsFrom the table our results

are highly significantthey are even significant at 0.1%meaning that our observed distribution is highly unlikely to come from aneven distribution randomly:i.e. There is a real effecthere

Knowledge issues: interpretationThe mathematical model tells us that there

the results are highly correlated (there is a strong correlation between the smoking behaviour of parents and that of their children)

But we need to do further work to establish causation

We would need to posit a mechanism – a piece of theory that uses general principles couched in psychological concepts to explain how one set of behaviours could cause the other

Models

Find a knowledge issue prompted by the following:The Federal Trade Commission has said that

advertisers and celebrities who endorse their products are liable for any untruthful statements they make regarding the effectiveness of their products – this includes statements they make on blogs and on social networking sites such as Twitter, Facebook and Myspace. (Financial Times 6 Oct 2009)