Read the paragraph and answer the questions that follow.

Are people ___ (i) ___ or even typically, guided by reason, rather than, say, by passion or impulse ? If the norms of rational behaviour are not followed by people in their actual behaviour, how can we seek the same answer to two rather different questions : what would be rational for a person to do ? And what would the person actually do ? Shouldn't the economists who make such double use of maximisation - whether through explicit reasoning ___ (ii) ___ by implicit presumption - be invited to apply their minds to this ?

A number of economists have indeed paid attention to systematic departures from rationality in actual choices made by people. One argument that has been invoked, in a line of reasoning proposed by Herbert Simon, goes by the name of bounded rationality. It concerns the possibility that people may not, in all cases, look for fully ___ (iii) ___ choices because of their inability to be sufficiently focussed. There is considerable evidence, powerfully presented, for example, ___ (iv) ___ Kahneman, Slovic and Tversky, that people may fail to understand adequately the nature of the uncertainty.