is unconstrained by convention. their brains have license to diverge and roam free. 18 education and adulthood put a stop to that. they constrain cognitive freedom. but there are means of freeing our brains from these constraints. for example, convening diverse groups can be seen as a means of adults rediscovering the creativity of childhood. it is a synthetic way of manufacturing divergent thinking, a sociological recipe for artificial intelligence that does not require a robot or a phd in physics. as childhood individualizes the creativity process, diversity can collectivise that process. at a micro level, there is fairly strong evidence for such an effect in communities, organisations and cities. in early societies, there is evidence of brides being given to other tribes and introducing new ideas and technologies. 19 inter - group marriage was, in effect, a vehicle for technology transfer. and, later, waves of migrant - merchants are believed to have served as a major stimulus to technology - transfer across civilised communities – for example, from the ancient orient to ancient greece. 20 mill ( 1848 ). for example, anderson and may ( 1979 ). for example, alesina et al ( 2015 ). land and jarman ( 1993 ), and land ( 2011 ). manning ( 2005 ). goldin et al bis central bankers ’ speeches coming closer to today, within organisations there is widespread evidence of diverse leadership teams improving firm - level performance. 21 there is also evidence of diverse workforces improving firm - level productivity, at least under certain conditions. 22 within cities, there is evidence from the us and europe of diverse, multicultural cities being a spur to economic development and growth. 23 richard florida argues that what defines a thriving city these days is the three “ t ” s – talent, technology and tolerance – with the third a key enabler of the first two. 24 at the macro level, the evidence is more mixed but in general suggests a positive relationship between diversity and economic growth. the historical experience of creatively - fertile empires, cities or epochs – from ancient greece to medieval florence, from elizabethan london to postrevolutionary paris – is suggestive. each of these social systems was notable for its cosmopolitan culture, with a rich mix of religions, ideas and disciplines. conversely, the cultural isolation of china for several centuries is held by some scholars to be responsible for its extended period of stifled innovation and growth. 25 more recent empirical evidence, looking across

? when you look at the four criteria that mario draghi has set as the metrics against which we assess the sustained adjustment it ’ s clear that some conditions are not yet met. for instance we need to be sufficiently confident that the rise is durable and will not reverse, which is the second criterion. when you look at measures of core inflation there has been an increase in april but the jury is still out as to how much of it is related to seasonal effects and particularly to easter and so it ’ s too early to conclude that there would be a sizeable upward 3 / 6 bis central bankers'speeches adjustment in core inflation. the third criterion was that we want to be reassured that the upward path in inflation can be maintained even in conditions in which monetary policy becomes less accommodative. and this also is not there. the future path of inflation remains dependent on a very substantial degree of monetary accommodation. so when you look at the four criteria, the conditions are not yet met. so are the other two ticked? the first crierion is that the path of inflation is expected to reach levels below but close to 2 percent within the medium term horizon. i would say broadly yes. by and large yes, based on current staff forecasts. but it also depends on what you call the medium term. the fourth criterion is about euro area inflation, and not the inflation of any individual country, which goes without saying. so the question is more about sustainability and not being reliant on our monetary support, and these are criteria 2 and 3. so we ’ re not there yet. we ’ re not yet at a stage where this strong demand for labour would translate into higher nominal wages. but at some point we ’ ll reach that point and then wages will start rising. there are good reasons to think we ’ ll get there. we ’ ve been in this initial stage of the recovery, where it has been a lot about part - time jobs and temporary contracts. of the net employment created since the crisis, around one third has been for workers under temporary contracts and around one quarter part - time. and undoubtedly the objective of these workers is to work more, not to get pay rises. but time will come when full - time and permanent jobs are created, and then wages will rise. taking it all together is this a cyclical upswing or a structural recovery? so far it ’ s entirely cyclical. in my view, the single most important issue for european