The Primary Judge's Ruling on Admissibility
40 On 1 March 2006, Darrell Lea gave written notice of its objections to evidence of Cadbury foreshadowed by affidavits sworn by a number of witnesses, including Roger Alexander Layton, Dr Gibbs and Messrs Stavros and Riches. While the rejection of Mr Layton's evidence is not in issue in the appeal, the objections concerning Dr Gibbs and Messrs Stavros and Riches were expressed in terms of the objections to Mr Layton's affidavit. It is necessary, therefore, to say something about those objections.
41 Mr Layton, Dr Gibbs and Messrs Stavros and Riches expressed opinions on the basis of Document Q. The objection to Mr Layton's evidence was that, generally, he had been asked to comment on research carried out by others, being the research referred to in Document Q, which had not been proved in the proceeding. The objection went on that Mr Layton had indicated that he had accepted assumptions with respect to the usage of purple as from 1998 only and yet expressed conclusions concerning conduct in Australia that predates 1998. The objection then asserted that Mr Layton had not carried out any relevant research of his own, displayed no independent knowledge of the relevant industry, other than as a personal consumer, which is not a basis for expert opinion, and expressed statements of opinion that were not "based on any demonstrated specialised knowledge". Consequently, it was said, his opinion was inadmissible under s 76 or s 135 of the Evidence Act. The objection then went on to say that, in so far as the opinion evidence was based upon research that had not been proved, the objection was based on the statements made by Heydon JA in Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705 (the Makita Case).
42 The same objection was made in respect of the affidavits of Messrs Stavros and Riches and Dr Gibbs. The objection in relation to Dr Gibbs went on to say that the references to unproved research reports in Document Q impacted on specific paragraphs of Dr Gibbs' affidavit dealing with the Cadbury brand.
43 After referring to the "argumentative nature" of opinions expressed about Darrell Lea, the objection went on to say that none of the evidence was based on admissible studies of consumer opinion or on the opinion of any actual consumer sought to be proved in the proceeding. Yet, so the objection ran, the opinion speculatively suggested an array of adverse consequences on consumer judgment arising from Darrell Lea's conduct, adopting the phrase "likely to cause". The objection ended by referring to the commentary in Dr Gibbs' affidavit on harm to Cadbury's business, notwithstanding that Cadbury itself had not sought to prove any such harm.
44 Senior counsel for Darrell Lea expounded on the objection orally. The entire thrust of the oral submission was that, proof of Document Q having been rejected, much of the observations made by Dr Gibbs were based on factual material and documents that would not be in evidence in the proceeding. The material and documents, however, were said to be the foundation of Dr Gibbs' opinions about the use of the colour purple by Cadbury and Darrell Lea.
45 Senior counsel for Darrell Lea eschewed any suggestion that there is not a speciality called marketing. The primary judge, in turn, referred to the Full Court's decision in Domain Names Australia Pty Ltd v .au Domain Administration Ltd [2004] FCAFC 247 (the Domain Names Case). His Honour referred to observations in that case (at [20]) to the effect that opinion evidence sought to be adduced as to the likely characteristics of recipients might be met by the observation of the High Court, in Transport Publishing Co Pty Ltd v The Literature Board of Review (1956) 99 CLR 111 (The Transport Publishing Case), that ordinary human nature, that of people at large, is not a subject of proof by evidence, whether supposedly expert or not.
46 The primary judge also referred to the observations made by the Full Court in the Domain Names Case (at [21]) that market research evidence has not been received with enthusiasm in the Federal Court in recent years in certain cases. His Honour then referred to observations made by Branson J in Cat Media Pty Ltd v Opti-Healthcare Pty Ltd [2003] FCA 133, cited in the Domain Names Case, to the effect that evidence of opinions based on market research and expert appreciation of consumer behaviour will rarely be of assistance in litigation where the Court's primary concern is with the behaviour to be expected of, and the judgments likely to be made by, ordinary members of the community intent on making a relatively modest purchase in a conventional way: where a claim is essentially a matter for the Court's impression, expert views that are merely impressionistic can be given no more than nominal weight.
47 Finally, his Honour referred to a statement in the Domain Names Case (at [22]) that consideration of such difficulties shows the practical wisdom of the firm rule that the likelihood of conduct being misleading or deceptive is a question for the tribunal of fact and not for any witness to decide. His Honour referred to the observations in the Domain Names Case (at [23]) that, while a different rule applies in the case of sales to participants in specialised markets involving persons engaged in a particular trade, that different rule would not apply in a case where the consumers in the market constitute large sections of the public rather than participants in a specialised market.
48 Senior counsel for Darrell Lea then went on to criticise statements in Dr Gibbs' affidavit as being pure speculation and not the proper subject of expert evidence. Senior Counsel asserted that Dr Gibbs had no personal knowledge relevant to the case and brought no relevant expertise. He asserted that Dr Gibbs was placed in a situation where he was venturing opinion without a proper foundation. He summarised the point in this way:
"Our point is simply this… there is a series of assumptions which underlie the giving of this evidence which, in short, are not proved and they are the very assumptions which underscore the commentary that your Honour will read [in Dr Gibbs affidavit]… [The assumptions are] not proved and not going to be proved in the case."
49 It is significant that no mention was made of s 80 of the Evidence Act in the course of the oral address by senior counsel for either party. In any event, the course of the interchange between senior counsel for Darrell Lea and the primary judge may serve to explain the conclusion that his Honour reached, and his Honour's reasons for the conclusion, without any reference to s 80 of the Evidence Act.
50 In the primary judge's ruling on the admissibility of Dr Gibbs' evidence, his Honour said that an expert's opinion is admissible to furnish the Court with scientific information that is likely to be outside the experience and knowledge of a judge or jury. His Honour suggested that the concept of specialised knowledge in s 79 imports knowledge of matters that are outside the knowledge or experience of an ordinary person, being knowledge that is sufficiently organised or recognised to be accepted as a reliable body of knowledge and that approach is very close to the common law approach. Thus, his Honour concluded that, even if a proffered opinion is that of a person suitably qualified within an organised area of knowledge, if that area is not outside the experience of ordinary persons, the opinion will not be admissible.
51 While his Honour accepted that marketing and behavioural science is an organised and recognised area of specialised knowledge and that Dr Gibbs has training, study and experience within that area, his Honour characterised the issues that arise in the case as not being outside the knowledge or experience of ordinary persons. His Honour concluded, therefore, that Dr Gibbs' evidence was inadmissible in its entirety, because it went only to a matter that is within the knowledge and experience of an ordinary person.
52 His Honour then referred to observations made by the High Court in the Transport Publishing Case at 119 to the effect that "ordinary human nature, that of people at large, is not a subject of proof by evidence, whether supposedly expert or not". Those observations, of course, were made before the enactment of s 80 of the Evidence Act. His Honour considered that the whole raison d'ętre of Dr Gibbs' evidence was to persuade the Court what ordinary human nature will lead people to do when making purchasing decisions about Darrell Lea chocolates, given the respective packaging, advertising, etc of that company and Cadbury. His Honour held that, before opinion evidence may be given upon the characteristics, responses or behaviour of any special category of persons, it must be shown that those persons form a subject of special study or knowledge.
53 The primary judge characterised the proceeding as being concerned with the brand names, colours and get-up of rival manufacturers of chocolate and the likely effect of those features on retail purchasing decisions by consumers. His Honour considered that virtually the whole of the Australian population over the age of about 8 years are purchasers or potential purchasers of chocolate, an inexpensive everyday product sold in hundreds of thousands of retail outlets throughout the country. His Honour did not consider that consumers of chocolates could be considered as a special category of persons that would constitute an exception to the rule under the common law. His Honour characterised the questions thrown up by the proceeding as "quintessentially questions of fact within the experience and knowledge of a trier of fact".
54 Such an approach appears to ignore the language of ss 79 and 80 of the Evidence Act. Certainly, opinion evidence will not be admissible unless the opinion is based on specialised knowledge and that specialised knowledge is in turn based on the opinion holder's training, study or experience. However, the former rule of the common law that excluded opinion evidence as to a matter of common knowledge no longer applies. Under s 80, evidence of an opinion is not inadmissible only because it is a matter of common knowledge.
55 Clearly enough, if the matter about which expert evidence is to be given is patent and known to all, the Court's time would normally be wasted by such evidence. Section 135 may be called in aid in those circumstances. Nevertheless, the evidence may still be strictly admissible. Further, an expert may still be of assistance to the Court, even in an area about which most people know something. So long as s 79 is satisfied, and the opinion evidence is based on specialised knowledge and that specialised knowledge is based on training, study or experience, that opinion evidence will be admissible, whether or not it might then be excluded in the exercise of the discretion conferred by s 135 (see generally the Law Reform Commission, Interim Report on Evidence, Canberra 1985, paragraph 743).
56 His Honour accepted Dr Gibbs' expertise and, for that purpose, that his opinion was based upon his expertise. Thus, his Honour accepted that the field of expertise was a recognised field and it may be accepted that his Honour did not reject Dr Gibbs' evidence on the ground that he did not have relevant expertise or that his opinion was not based upon his specialised knowledge.
57 The primary judge concluded, however, that it is a condition of the admissibility of opinion evidence that the opinion relates to an issue that is outside the knowledge or experience of ordinary persons. In so far as that was the reason for concluding that the opinions of Dr Gibbs were inadmissible, his Honour erred. The fact that an opinion is expressed concerning the making of consumer decisions for the purchase of everyday items of commerce does not disqualify the opinion from being admissible, so long as s 79 is satisfied.
58 In his ruling, the primary judge observed that the prime ground upon which senior counsel for Darrell Lea argued against the admissibility of the disputed evidence was that much of the opinion evidence was based on market research reports that had not been proved in evidence and were not likely to be proved. However, his Honour accepted the submissions of senior counsel for Cadbury that the lack of proof of a substantial part of the factual basis of Dr Gibbs' opinions does not of itself render his evidence inadmissible under s 79. His Honour considered that such lack of proof merely goes to the weight that may be given to the opinion. Darrell Lea did not contest that view of s 79 in the appeal. It is therefore not necessary to address the question, or the application of the statements made by Heydon JA in the Makita case. Our failure to do so should not necessarily be taken as endorsement of the correctness of the view adopted by the primary judge.
59 After his Honour had delivered written reasons for his ruling that Dr Gibbs' affidavits not be admitted into evidence, senior counsel for Cadbury proceeded to deal with the affidavits of Mr Stavros but observed that the objection to those affidavits was the same as the objection to the affidavits of Dr Gibbs. Senior counsel accepted that Mr Stavros' affidavits would be unsustainable in the light of his Honour's ruling in relation to Dr Gibbs.
60 His Honour observed that, notwithstanding the submissions as to the nature of Mr Stavros' particular experience, the same problem arose as arose with Dr Gibbs. That problem was that the proposed evidence was that of expert opinion in relation to the behaviour of ordinary people in consumer decisions and fell squarely within the grounds of the earlier ruling. His Honour therefore ruled that he would not receive Mr Stavros' affidavits.
61 Subsequently, his Honour dealt with the objection in relation to Mr Riches' affidavit and noted that the argument was the same as that put in respect of Dr Gibbs. His Honour observed that, while Mr Riches may approach the matter from a background somewhat different from that of the other two witnesses, his Honour considered that the evidence had essentially the same vice, in that it expressed opinions about how people are likely to react about consumers' purchases. His Honour therefore declined to receive the affidavit of Mr Riches.