Human echolocation: pitch versus loudness information

Blind persons emit sounds to detect objects by echolocation. Both perceived pitch and perceived loudness of the emitted sound change as they fuse with the reflections from nearby objects. Blind persons generally are better than sighted at echolocation, but it is unclear whether this superiority is related to detection of pitch, loudness, or both. We measured the ability of twelve blind and twenty-five sighted listeners to determine which of two sounds, 500 ms noise bursts, that had been recorded in the presence of a reflecting object in a room with reflecting walls using an artificial head. The sound pairs were original recordings differing in both pitch and loudness, or manipulated recordings with either the pitch or the loudness information removed. Observers responded using a 2AFC method with verbal feedback. For both blind and sighted listeners the performance declined more with the pitch information removed than with the loudness information removed. In addition, the blind performed clearly better than the sighted as long as the pitch information was present, but not when it was removed. Taken together, these results show that the ability to detect pitch is a main factor underlying high performance in human echolocation.     

Differences in consumer preferences when facing branded versus non‐branded choices

Because brands can signal reputation and serve as proxies for trust, consumer preferences for credence attributes may differ for branded and non‐branded products. We test this hypothesis using data from a choice experiment conducted with US pork consumers. The results indicate that consumers are usually willing to pay more for a certification attribute in a non‐branded as compared to branded product. Additionally, greater variation in consumer willingness‐to‐pay for credence attributes is observed in the non‐branded case. This latter characteristic of the results may represent the increased uncertainty some consumers internalize concerning quality consistency when brand information is not provided. These results have interesting implications for producers, processors, retailers, and policy makers. Copyright © 2011 John Wiley & Sons, Ltd.     

Representation at different levels in a conceptual hierarchy

The present study examines the influence of hierarchical level on category representation. Three computational models of representation – an exemplar model, a prototype model and an ideal representation model – were evaluated in their ability to account for the typicality gradient of categories at two hierarchical levels in the conceptual domain of clothes. The domain contains 20 subordinate categories (e.g., trousers, stockings and underwear) and an encompassing superordinate category (CLOTHES). The models were evaluated both in terms of their ability to fit the empirical data and their generalizability through marginal likelihood. The hierarchical level was found to clearly influence the type of representation: For concepts at the subordinate level, exemplar representations were supported. At the superordinate level, however, an ideal representation was overwhelmingly preferred over exemplar and prototype representations. This finding contributes to the increasingly dominant view that the human conceptual apparatus adopts both exemplar representations and more abstract representations, contradicting unitary approaches to categorization.     

Multiple-look effects on temporal discrimination within sound sequences

The multiple-look notion holds that the difference limen (DL) decreases with multiple observations. We investigated this notion for temporal discrimination in isochronous sound sequences. In Experiment 1, we established a multiple-look effect when sequences comprised nine standard time intervals (S) followed by an increasing number of comparison time intervals (C), but no multiple-look effect when one trailing C interval was preceded by an increasing number of S intervals. In Experiment 2, we extended the design. There were four sequential conditions: (a) 9 leading S intervals followed by 1, 2, …, or 9 C-intervals; (b) 9 leading C intervals followed by 1, 2, …, or 9 S intervals; (c) 9 trailing C-intervals preceded by 1, 2, …, or 9 S-intervals; and (d) 9 trailing S-intervals preceded by 1, 2, …, or 9 C-intervals. Both the interval accretions before and after the tempo change caused multiple-look effects, irrespective of the time order of S and C. Complete deconfounding of the number of intervals before and after the tempo change was accomplished in Experiment 3. The multiple-look effect of interval accretion before the tempo change was twice as big as that after the tempo change. The diminishing returns relation between the DL and interval accretion could be described well by a reciprocal function.     

Examination of the processing speed account in a population-based longitudinal study with narrow age cohort design

The processing speed account suggests that general slowing of mental processing speed results in an overall decline, especially age-related decline, in other cognitive domains. Support for the speed account comes mainly from cross-sectional studies with participants that vary in age (age-heterogeneous samples). This study investigated how well variations in processing speed predict change of episodic recall in a longitudinal framework and examined with the Narrow Age Cohort (NAC) design. Data were obtained from Betula, a population-based longitudinal study. Both 5-year (n= 490; Time 3 - Time 4) and 10-year follow-up results (n= 608; Time 1 - Time 3) were used. In both samples, which were subjected to prospective dementia screening, we found considerably weaker associations in longitudinal data compared to cross-sectional, and also weaker associations in age-homogeneous than in age-heterogeneous samples. The results provide little support for the speed account.     

Exemplars and prototypes in natural language concepts: A typicality-based evaluation

Are natural language categories represented by instances of the category or by a summary representation? We used an exemplar model and a prototype model, both derived within the framework of the generalized context model (Nosofsky, 1984, 1986), to predict typicality ratings for 12 superordinate natural language concepts. The models were fitted to typicality ratings averaged across participants and to the typicality judgments of individual participants. Both analyses yielded results in favor of the exemplar model. These results suggest that higher-level natural language concepts are represented by their subordinate members, rather than by a summary representation.     

Problems for Moral Twin Earth Arguments*

Terry Horgan and Mark Timmons have recently presented a series of papers in which they argue against what has come to be called the ‘new wave’ moral realism and moral semantics of David Brink, Richard Boyd, Peter Railton, and a number of other philosophers. The central idea behind Horgan and Timmons’s criticism of these ‘new wave’ theories has been extended by Sean Holland to include the sort of realism that drops out of response-dependent accounts that make use of an analogy between moral properties and secondary qualities. This paper argues that Holland’s extension depends crucially on the fact that his target is a direct response-dependent account of moral value. His argument does not work against such accounts of more basic normative notions such as ‘harm’ or ‘benefit’. And these more basic notions may then serve as the basic normative building blocks for an indirectly response-dependent moral theory. * Thanks to Mark Timmons for helpful and friendly comments on an earlier version of this paper, and also to an audience at the 2003 Pacific APA, and to the reviewers for this journal.     

老化和其他研究领域中认知心理学与认知神经科学的整合

I am happy to present a series of articles in this issue of Acta Psychologica Sinica. I was invited to do so and here is the outcome. The articles have been written by researchers living and working outside China. None of them has made a contribution to this journal before. The articles cover a broad spectrum of topics within the area of cognitive neuroscience. The purpose of this little article is to introduce the authors and the topics covered to the readership of the journal.