You knew where you were with Scotland's rugby captains in the 1980s and early 1990s.

Jim Aitken, Finlay Calder, David Sole . . . the sort of indomitable characters, whose searing gaze could eviscerate a lazy tackler or slipshod passer at 100 paces, and who were capable of seizing destiny by the scruff of the neck and turning matters to their advantage.

On and off the pitch, these men were intense individuals, and although Calder always spoke with intelligence and a cerebral air, he was never in any danger of being described as "nice". He wanted his men to be winners, to fling themselves into the fray and intimidate the opposition. Remember how he tried a Zidane-style manoeuvre on Sean Fitzpatrick in his farewell match in 1991?

But fast forward 20 or 30 years and what do we have? The story of a series of captains who are genuinely smashing blokes, but don't appear to possess an ounce of malice or a nasty streak in their bodies.

Current incumbent Kelly Brown, who was dropped from the squad for today's match, is a talented performer and all-round good guy, but when he marched his men into the dressing room at the Aviva Stadium in Dublin last weekend, could anybody imagine him tearing strips off the professionals who had spent the preceding 40 minutes winning over 60% of possession and doing virtually nothing with it? It just isn't in the man's nature and there, to some extent, lies one of the problems with Scottish rugby and why the national side's fortunes have declined of late.

The fear of failure appears to be lacking, which in turn has resulted in the same names being chosen time after time, despite the evidence that they are either stuck in neutral gear or actually ploughing backwards at a rate of knots.

When I mentioned this phenomenon to a colleague, he responded with a phrase which struck a chord, saying: "Yes, it's the rise of the softies." Harsh, of course, and one would hesitate to utter that remark anywhere near Al Kellock, who brought a juddering intensity to his efforts whenever he took the Scots into battle. And yet there has been a placid, even-tempered approach from many of our recent leaders, which seems at odds with the whirling dervish approach of captains, players and commentators from other countries. Jason White, for instance, oozes integrity and decency and is fashioned in Brown's mould.

Similarly, Chris Paterson, the nation's record accumulator of caps, is so thoroughly likeable that he could have moved from advertising porridge to appearing alongside Woody and Buzz Lightyear in a Pixar production. Gavin Hastings was so disappointed with his penalty misses - and last-gasp victory for the English - at Murrayfield in 1994 that he shed tears in front of Dougie Donnelly. That was maybe understandable amid his frustration and quiet fury with the refereeing decision which gifted the visitors their undeserved win. But it set a trend.

Since then, for the most part, the skippers have been lovely fellows. And, apart from in 1999, when Gary Armstrong flung himself with his usual stakhanovite relish into the faces of his opponents as Scotland triumphed in the last Five Nations, the amiable demeanour of Scottish captains has coincided with the team's rapid plummet down the IRB rankings.

There is little point in expecting Brown to morph into the Incredible Hulk. Nor does the team's predicament simply boil down to a question of leadership abilities because, as Calder once declared, anybody could take charge of a team and prosper if he was surrounded by Test-class confreres. However, recent history suggests that the Scots urgently require an injection of needle and a resurgence of the old mongrel which made them so hard to beat under Jim Telfer, when scary performers such as John Beattie, David Leslie, Aitken and Calder, indulged in every form of psychological warfare and terrified the wits out of many adversaries.

Cast your gaze around the present squad and there are plenty of friendly giants. Richie Gray: a rugby-playing Gentle Ben. Ross Ford: the antithesis of snarling, girning Brian Moore. Even Beattie Jnr has little of the visceral qualities which made his father such a fearsome competitor.

So why is that? Have Scotland lost their bellicose, bruising intensity during the last two decades? Or might Duncan Weir be the sort of no-nonsense figure who could operate as captain in the style of domineering figures from the past?