Commentary Research on gene–environment interdependence: Honing the tools and examining the angles

The insightful overview by Sir Michael Rutter (this issue) on gene–environment interdependence comes about 10 years after the breakthrough Science publications on gene–environment interactions (G×E) involving the MAOA and 5-HTT genes by Caspi et al. (2002 Caspi, A., McClay, J., Moffitt, T. E., Mill, J., Martin, J.Craig, I. W. 2002. Role of genotype in the cycle of violence in maltreated children. Science, 297: 851–854. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 2003 Caspi, A., Sugden, K., Moffitt, T. E., Taylor, A., Craig, I. W.Harrington, H. 2003. Influence of life stress on depression: Moderation by a polymorphism in the 5-HTT gene. Science, 301: 386–389. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Since then, a field of research has burgeoned that has produced replications as well as intriguing new evidence of gene–environment interdependence. At the same time, however, the field has witnessed a growing scepticism about the relevance of studying gene–environment interactions and has seen replication failures (see Duncan & Keller, 2011 Duncan, L. E. and Keller, M. C. 2011. A critical review of the first 10 years of candidate gene-by-environment interaction research in psychiatry. American Journal of Psychiatry, 168: 1041–1049. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Risch et al., 2009 Risch, N., Herell, R., Lehner, T., Liang, K.-Y., Eaves, L.Hoh, J. 2009. Interaction between the serotonin transporter gene (5-HTTLPR), stressful life events, and risk of depression: A meta-analysis. Journal of the American Medical Association, 301: 2462–2471. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Against this backdrop, we comment and elaborate on several of the key issues raised by Rutter, and suggest some directions for future research on G×E. Specifically, we discuss (1) replication issues; (2) the crucial role of experiments in understanding gene–environment interdependence; (3) current unknowns with regard to differential susceptibility; and (4) clinical and practical implications of G×E research.     

Local and global processing biases fail to influence face,object, and word recognition

Three studies investigated whether encouraging people to use either global or local processing using the Navon task (Navon, 1977 Navon, D. 1977. Forest before the trees: The precedence of global features in visual perception. Cognitive Psychology, 9: 353–383. [Crossref], [Web of Science ®] , [Google Scholar]) influenced recognition memory for upright and inverted pictures of faces, objects, and words. Contrary to the striking results of Macrae and Lewis (2002 Macrae, C. N. and Lewis, H. L. 2002. Do I know you? Processing orientation and face recognition. Psychological Science, 13: 194–196. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), no effect of such cross-task processing biases were found. In particular, encouraging global processing did not improve the recognition of upright faces, whilst encouraging local processing failed to improve the recognition of words. These results suggest that using the Navon task to manipulate people's processing strategy typically does not have a large, consistent effect on recognition memory. Instead, prior performance of an unrelated task may only influence subsequent recognition memory under restricted circumstances. Therefore, the cross-task processing bias effect does not provide researchers with a powerful, reliable tool with which to investigate the relative importance of local versus global, configural processing of visual stimuli.     

Face familiarity,distinctiveness, and categorical perception

Four experiments with faces support the original interpretation of categorical perception (CP) as only present for familiar categories. Unlike in the results of Levin and Beale (2000) Levin, D. T. and Beale, J. M. 2000. Categorical perception occurs in newly learned faces, other-race faces, and inverted faces. Perception & Psychophysics, 62: 386–401. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], no evidence is found for face identity CP with unfamiliar faces. Novel face identities were shown to be capable of encoding for immediate sorting purposes but the representations utilized do not have the format of perceptual categories. One possibility explored was that a choice of a distinctive face as an end-point in a morphed continuum can spuriously produce effects that resemble CP. Such morphed continua provided unequal psychological responses to equal physical steps though much more so in a better likeness paradigm than for forced-choice recognition. Thus, researchers doing almost the same experiments may produce very different results and come to radically different conclusions.     

Priming the trait category “hostility”: The moderating role of trait anxiety

Recent studies on affective priming with the naming task have revealed an influence of trait anxiety on the direction of affective priming effects (e.g., Berner & Maier, 2004 Berner, M. P. and Maier, M. A. 2004. The direction of affective priming as a function of trait anxiety when naming target words with regular and irregular pronunciation. Experimental Psychology, 51: 180–190. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). This moderating role of trait anxiety was further investigated in a study employing a conceptual priming task. After masked presentation of either hostile or neutral primes, participants performed a person judgment task. As expected, the direction of the hostility rating difference score, defined as the difference between hostility ratings of a target person in the hostility priming condition and in the neutral priming condition, changed from positive to negative with increasing levels of self-reported trait anxiety. The findings are interpreted in terms of salience-dependent overcorrection processes (Glaser & Banaji, 1999 Glaser, J. and Banaji, M. R. 1999. When fair is foul and foul is fair: Reverse priming in automatic evaluation. Journal of Personality and Social Psychology, 77: 669–687. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Implications for our understanding of the cognitive functioning in high trait anxiety are discussed.     

Response-level probability effects on reaction time: Now you see them,now you don't

Many reaction time (RT) experiments have tested for response-level probability effects. Their results have been mixed, which is surprising because psychophysiological studies provide clear evidence of motor-level changes associated with an anticipated response. A survey of the designs used in the RT studies reveals many potential problems that could conceal the effects of response probability. We report five new RT experiments testing for response-level probability effects with the most promising of the previous designs—that of Blackman (1972 Blackman, A. R. 1972. Influence of stimulus and response probability on decision and movement latency in a discrete choice reaction task. Journal of Experimental Psychology, 92: 128–133. doi:10.1037/h0032169[Crossref], [PubMed] , [Google Scholar])—and with new designs. Some of these experiments yield evidence of response-level probability effects, but others do not. It appears that response-level probability effects are present primarily in simple tasks with a strong emphasis on response preparation, possibly because participants only expend effort on response preparation in these tasks.     

Decomposing the emotional Stroop effect

The emotional Stroop effect refers to the phenomenon that participants are faster in responding to the ink colour of neutral than of negative word stimuli, possibly reflecting fast and automatic allocation of attention towards negative stimuli. However, this interpretation was challenged by McKenna and Sharma (2004) McKenna, F. P. and Sharma, D. 2004. Reversing the emotional Stroop effect reveals that it is not what it seems: The role of fast and slow components. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30: 382–392. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] who found that the emotional Stroop effect reflected a generic slowdown after negative stimuli. In fact, they even found reversed effects in a design in which neutral stimuli more often followed negative stimuli and vice versa. Yet, besides reversing the emotional Stroop effect this contingency might in fact have counteracted the fast effect, which was usually interpreted as the emotional Stroop effect. To decompose the emotional Stroop effect we used a design in which the foregoing and the current valence were uncorrelated and in which the fast and slow effects could be computed independently from each other. We found evidence for both fast and slow effects and discuss the practical implications for researchers using the emotional Stroop task as a measurement and the theoretical implications for researchers interested in the underlying cognitive mechanisms that contribute to the emotional Stroop effect.     

Transfer Effects in Children's Recall of Arithmetic Facts

Predictions of the Identical Elements (IE) model of arithmetic fact representation (Rickard, 2005 Rickard, T. C. 2005. A revised identical elements model of arithmetic fact representation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31: 250–257. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Rickard & Bourne, 1996 Rickard, T. C. and Bourne, L. E. 1996. Some tests of an identical elements model of basic arithmetic skills. Journal of Experimental Psychology: Learning, Memory, and Cognition, 22: 1281–1295. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) about transfer between arithmetic facts were tested in primary school children. The aim of the study was to test whether the IE model, constructed to explain adult performance, also applies to children. The IE model predicts no positive transfer when the numerical elements of a test problem do not match exactly with those of a practice problem. In two experiments, children practiced addition or multiplication problems. A large positive transfer effect was found for problems with an operand order change; improvement was just as high as for practiced problems. Smaller transfer effects were found for problems where one operand was increased with one unit and for problems with operands more different from practice problems. Analogous results were found for addition and multiplication, suggesting that storage and retrieval processes in both domains are similar in children. The findings suggest that there is a gradual decrease in transfer as the test problems become more different from practice problems, indicating that a more sophisticated model than the IE model is needed to explain transfer effects in children's recall of arithmetic facts.     

Intentionality Attributions About Perfect and Imperfect Duty Violations

Abstract

Intentionality attributions were explored by drawing on the distinction between perfect and imperfect moral duties. Previous research has shown that perfect duty violations carry greater attributional weight than imperfect duty violations (Trafimow & Trafimow, 1999 Trafimow, D. and Trafimow, S. 1999. Mapping imperfect and perfect duties on to hierarchically and partially restrictive trait dimensions. Personality and Social Psychology Bulletin, 25: 686–695. [Crossref], [Web of Science ®] , [Google Scholar]; Trafimow, Bromgard, Finlay, & Ketelaar, 2005 Trafimow, D., Bromgard, I. K., Finlay, K. A. and Ketelaar, T. 2005. The role of affect in determining the attributional weight of immoral behaviors. Personality and Social Psychology Bulletin, 31: 935–948. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). In Studies 1 and 2, the distinction between perfect and imperfect duties was replicated with intentionality judgments, and perfect duty violations received higher intentionality attributions than imperfect duty violations. In Study 3 this effect was reversed by manipulating information about an agent's mental intentions or plans to perform a behavior. That is, participants attributed less intentionality to perfect duty violations compared to imperfect duty violations when a mental intention to perform the behavior was absent.     

On the Overuse and Misuse of Mediation Analysis: It May Be a Matter of Timing

Kenny (2008) credited Hyman (1955 Hyman, H. (1955). Survey design and analysis: Principles, cases and procedures. Glencoe, IL: The Free Press. [Google Scholar]) with originally discussing mediation analysis under the name elaboration. Of importance, Hyman's elaboration required a time-ordered relationship among variables, such that the mediator must always intervene in time between the predictor and outcome. However, in the modern discussions of mediation (e.g., Baron & Kenny, 1986 Baron, R., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182. doi:10.1037/0022-3514.51.6.1173[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Preacher & Hayes, 2004 Preacher, K. J., & Hayes, A. F. (2004). SPSS and SAS procedures for estimating indirect effects in simple mediation models. Behavior Research Methods, Instruments, & Computers, 36, 717–731. doi:10.3758/bf03206553[Crossref], [PubMed] , [Google Scholar]), this crucial point about time-ordered relationships appears to be underemphasized. This article shows that by employing a conceptual timing criterion for all mediation analyses, the overuse of this technique can be curbed, and, simultaneously, researchers will understand when mediation analyses are appropriate across the behavioral and medical science literatures.     

Homophonic context effects when naming Japanese kanji: evidence for processing costs?

The current study investigated the effects of phonologically related context pictures on the naming latencies of target words in Japanese and Chinese. Reading bare words in alphabetic languages has been shown to be rather immune to effects of context stimuli, even when these stimuli are presented in advance of the target word (e.g., Glaser & Düngelhoff, 1984 Glaser, W. R. and Düngelhoff, F. J. 1984. The time course of picture–word interference. Journal of Experimental Psychology: Human Perception and Performance, 10: 640–654. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Roelofs, 2003 Roelofs, A. 2003. Goal-referenced selection of verbal action: Modeling attentional control in the Stroop task. Psychological Review, 110: 88–125. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). However, recently, semantic context effects of distractor pictures on the naming latencies of Japanese kanji (but not Chinese hànzì) words have been observed (Verdonschot, La Heij, & Schiller, 2010 Verdonschot, R. G., La Heij, W. and Schiller, N. O. 2010. Semantic context effects when naming Japanese kanji, but not Chinese hànzì. Cognition, 115: 512–518. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). In the present study, we further investigated this issue using phonologically related (i.e., homophonic) context pictures when naming target words in either Chinese or Japanese. We found that pronouncing bare nouns in Japanese is sensitive to phonologically related context pictures, whereas this is not the case in Chinese. The difference between these two languages is attributed to processing costs caused by multiple pronunciations for Japanese kanji.     

The influence of discrete emotions on judgement and decision-making: A meta-analytic review

During the past three decades, researchers interested in emotions and cognition have attempted to understand the relationship that affect and emotions have with cognitive outcomes such as judgement and decision-making. Recent research has revealed the importance of examining more discrete emotions, showing that same-valence emotions (e.g., anger and fear) differentially impact judgement and decision-making outcomes. Narrative reviews of the literature (Lerner & Tiedens, 2006 Lerner, J. S. and Tiedens, L. Z. 2006. Portrait of the angry decision maker: How appraisal tendencies shape anger's influence on cognition. Journal of Behavioral Decision-Making, 19: 115–137. [Crossref], [Web of Science ®] , [Google Scholar]; Pham, 2007 Pham, M. T. 2007. Emotion and rationality: A critical review and interpretation of empirical evidence. Review of General Psychology, 11(2): 155–178. [Crossref], [Web of Science ®] , [Google Scholar]) have identified some under-researched topics, but provide a limited synthesis of findings. The purpose of this study was to review the research examining the influence of discrete emotions on judgement and decision-making outcomes and provide an assessment of the observed effects using a meta-analytic approach. Results, overall, show that discrete emotions have moderate to large effects on judgement and decision-making outcomes. However, moderator analyses revealed differential effects for study-design characteristics and emotion-manipulation characteristics by emotion type. Implications are discussed.     

Core verbal working-memory capacity: The limit in words retained without covert articulation

Verbal working memory may combine phonological and conceptual units. We disentangle their contributions by extending a prior procedure (Chen & Cowan, 2005 Chen, Z. and Cowan, N. 2005. Chunk limits and length limits in immediate recall: A reconciliation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31: 1235–1249. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) in which items recalled from lists of previously seen word singletons and of previously learned word pairs depended on the list length in chunks. Here we show that a constant capacity of about 3 chunks holds across list lengths and list types, provided that covert phonological rehearsal is prevented. What remains is a core verbal working-memory capacity.     

What are the Origins of Shamanic Journeying Imagery? The Modification of a Hypnoanalytic Technique to Address an Enduring Methodological Problem

Shamanic journeying imagery arguably transcends geographical space and historical time. However, to what extent is the content of the journeying imagery a construction of the shaman's cultural cosmology, belief systems, autobiographical memories, etc? It is suggested that attempts to answer this question are hampered by a fundamental methodological obstacle: how to detect contextual influences on imagery that the shaman cannot report on because they are outside his/her present awareness and memory. A partial solution is presented: Watkins' (1971) Watkins, J. G. 1971. The affect bridge: A hypnoanalytic technique.. The International Journal of Clinical and Experimental Hypnosis, 19: 21–27. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar] Affect Bridge, a hypnoanalytic technique used to uncover the origin of an affect. A nonhypnotic version of the technique developed for inquiry into shamanic journeying imagery is then explicated. Two recent empirical studies conducted by Rock (2006) Rock, A. J. 2006. Phenomenological analysis of experimentally induced visual mental imagery associated with shamanic journeying to the lower world.. International Journal of Transpersonal Studies, 25: 45–55.  [Google Scholar] and Rock, Casey and Baynes (2006) Rock, A. J., Casey, P. J. and Baynes, P. B. 2006. Experimental study of ostensibly shamanic journeying imagery in naive participants II: Phenomenological mapping and modified affect bridge.. Anthropology of Consciousness, 17(1): 65–83. [Crossref] , [Google Scholar], illustrating the utility of the Modified Affect Bridge with regards to investigating experimentally the origin of ostensibly shamanic journeying imagery reported by naive participants, are summarized. A tentative ostensibly shamanic journeying imagery origin typology is formulated and suggestions for future research are advanced.     

Cross-notational semantic priming between symbolic and nonsymbolic numerosity

Symbolic and nonsymbolic numerosities produce similar behavioural effects and activate the same brain areas. These results have usually been interpreted in terms of a common, notation-independent magnitude representation. However, semantic priming between symbolic and nonsymbolic inputs has been somehow elusive (e.g., Koechlin, Naccache, Block, & Dehaene, 1999 Koechlin, E., Naccache, L., Block, E. and Dehaene, S. 1999. Primed numbers: Exploring the modularity of numerical representations with masked and unmasked semantic priming. Journal of Experimental Psychology: Human Perception and Performance, 25: 1882–1905. [Crossref], [Web of Science ®] , [Google Scholar]). In Experiment 1, we looked at whether cross-notational semantic priming depends on exact numerical meaning. Dice faces and digits were mixed as prime and target. Semantic priming occurred when prime and target were in the same notation as much as when they were in different notation. In Experiment 2, we found cross-notation semantic priming even when the nonsymbolic numerosity was presented as a set of random dots. Priming, however, occurred only from sets of dots to digit, not vice versa. These data support the computational model recently proposed by Verguts and Fias (2004 Verguts, T. and Fias, W. 2004. Representation of number in animals and humans: A neural model. Journal of Cognitive Neuroscience, 16: 1493–1504. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Verguts, Fias, & Stevens, 2005 Verguts, T., Fias, W. and Stevens, M. 2005. A model of exact small-number representation. Psychonomic Bulletin & Review, 112: 66–80.  [Google Scholar]).     

Categorical effects in visual search for colour

The role of categorization in visual search was studied in 3 colour search experiments where the target was or was not linearly separable from the distractors. The linear separability effect refers to the difficulty of searching for a target that falls between the distractors in CIE colour space (Bauer, Jolicoeur, & Cowan, 1996b Bauer, B., Jolicoeur, P. and Cowan, W. B. 1996b. Visual search for colour targets that are or are not linearly separable from distractors. Vision Research, 36: 1439–1465. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Observers performed nonlinearly separable searches where the target fell between the two types of distractors in CIE colour space. When the target and distractors fell within the same category, search was difficult. When they fell within three distinct categories, response times and search slopes were significantly reduced. The results suggest that categorical information, when available, facilitates search, reducing the linear separability effect.     

Dissociative effects of true and false recall as a function of different encoding strategies

Goodwin, Meissner, and Ericsson (2001 Goodwin, K. A., Meissner, C. A. and Ericsson, K. A. 2001. Toward a model of false recall: Experimental manipulation of encoding context and the collection of verbal reports. Memory & Cognition, 29: 806–819. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) proposed a path model in which elaborative encoding predicted the likelihood of verbalisation of critical, nonpresented words at encoding, which in turn predicted the likelihood of false recall. The present study tested this model of false recall experimentally with a manipulation of encoding strategy and the implementation of the process-tracing technique of protocol analysis. Findings indicated that elaborative encoding led to more verbalisations of critical items during encoding than rote rehearsal of list items, but false recall rates were reduced under elaboration conditions (Experiment 2). Interestingly, false recall was more likely to occur when items were verbalised during encoding than not verbalised (Experiment 1), and participants tended to reinstate their encoding strategies during recall, particularly after elaborative encoding (Experiment 1). Theoretical implications for the interplay of encoding and retrieval processes of false recall are discussed.     

The Difference Between Being and Seeing: The Relative Contribution of Self-Perception and Priming to Behavioral Changes via Digital Self-Representation

Studies in the Proteus Effect (N. Yee & J. Bailenson, 2007 Yee, N. and Bailenson, J. 2007. The proteus effect: The effect of transformed self-representation on behavior. Human Communication Research, 33: 271–290. [Crossref], [Web of Science ®] , [Google Scholar]) have shown that the appearance of avatars (i.e., digital representations of ourselves) can lead to behavioral changes in users. For example, participants in attractive avatars became friendlier to confederate strangers than participants in unattractive avatars. While the Proteus Effect is premised on self-perception theory (D. Bem, 1972 Bem, D. 1972. “Self-perception theory.”. In Advances in experimental social psychology Edited by: Berkowitz, L. Vol. 6, New York: Academic Press. [Crossref] , [Google Scholar])—the notion that we infer our own attitudes by observing ourselves as if from a third party—it is also possible that the previous findings were caused by priming (i.e., behavioral assimilation; J. Bargh, M. Chen, & L. Burrows, 1996 Bargh, J., Chen, M. and Burrows, L. 1996. The automaticity of social behaviour: Direct effects of trait concept and stereotype activation on action. Journal of Personality and Social Psychology, 71: 230–244. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). In our study, we used immersive virtual environment technology to experimentally tease apart embodiment from perception of the same visual stimulus. Our results showed that embodiment produced significantly larger behavioral changes than mere observation of the same visual stimuli. These findings support the claim that our avatars provide a unique lever to behavioral change; however, more work is needed to pin down the exact mechanism behind the effect.     

Controlling reactive aggression through cognitive evaluation of proactive aggression cues

The authors investigated how the relationship between the acts of proactive and reactive aggression was moderated by the individual differences in cognitive regulation of emotion. An aggression paradigm, a electrocardiogram recording, a cognitive assessment battery, and a short form IQ test were completed by 109 children, aged 8 to 13 years (Juujärvi, Kaartinen, Laitinen, Vanninen, & Pulkkinen, 2006 Juujärvi, P., Kaartinen, J., Laitinen, T., Vanninen, E. and Pulkkinen, L. 2006. Effects of physical provocations on heart rate reactivity, and reactive aggression in children. Aggressive Behavior, 32: 99–109. [Crossref], [Web of Science ®] , [Google Scholar]; Juujärvi, Kooistra, Kaartinen, & Pulkkinen, 2001 Juujärvi, P., Kooistra, L., Kaartinen, J. and Pulkkinen, L. 2001. An aggression machine: V. Determinants of reactive aggression revisited. Aggressive Behavior, 27: 430–445. [Crossref], [Web of Science ®] , [Google Scholar]; Lehto, Juujärvi, Kooistra, & Pulkkinen, 2003 Lehto, J. E., Juujärvi, P., Kooistra, L. and Pulkkinen, L. 2003. Dimensions of executive functioning: Evidence from children. British Journal of Developmental Psychology, 21: 59–80. [Crossref], [Web of Science ®] , [Google Scholar]). The less the children subdued the intensity of their defence to the attacks in the aggression paradigm, the poorer they performed in the cognitive assessment battery tasks measuring Working memory capacity and in the task assessing crystallised intelligence. The mean cardiovascular reactivity during the aggression paradigm was neither associated with the performances in either the cognitive assessment battery nor the intelligence tasks. Both information processing and knowledge dimensions of cognition contributed to regulation of emotion, but the respective effects of the processes cannot be inferred from the mean cardiovascular reactivity.     

Sport-Type Differences in Alcohol Use Among Intercollegiate Athletes

Prior research has found that (a) intercollegiate athletes are especially “at-risk” for excessive alcohol consumption (e.g., Nelson & Wechsler, 2001 Nelson, T. F. and Wechsler, H. 2001. Alcohol and college athletes. Medicine and Science in Sports and Exercise, 33: 43–47. [INFOTRIEVE][CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), and (b) sport-type differences exist among college athletes in terms of yearly drinking prevalence rates (National Collegiate Athletic Association, 2001 National Collegiate Athletic Association. 2001. NCAA study of substance use habits of college student-athletes, Indianapolis, IN: Author.  [Google Scholar]). No studies, however, have examined sport-type differences on more specific measures of alcohol consumption (e.g., drinks per week), or examined potential mediators of the relationship between sport type and alcohol consumption. In the present study, data were analyzed on 298 intercollegiate athletes from two different universities. Resuls indicated significant sport type differences on alcohol consumption variables, with athletes from the sports of swimming and diving reporting the highest levels of alcohol consumption. Results provided partial support for the role of positively reinforcing drinking motives in mediating the sport type–alcohol consumption relationship. Findings are discussed in light of prior research in the area of college student–athlete alcohol consumption.     

The representational space of numerical magnitude: Illusions of length

In recent years, a growing amount of evidence concerning the relationships between numerical and spatial representations has been interpreted, by and large, in favour of the mental number line hypothesis—namely, the analogue continuum where numbers are spatially represented (Dehaene, 1992 Dehaene, S. 1992. Varieties of numerical abilities. Cognition, 44: 1–42. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Dehaene, Piazza, Pinel, & Cohen, 2003 Dehaene, S., Piazza, M., Pinel, P. and Cohen, L. 2003. Three parietal circuits of number processing. Cognitive Neuropsychology, 20: 487–506. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). This numerical representation is considered the core of number meaning and, accordingly, needs to be accessed whenever numbers are semantically processed. The present study explored, by means of a length reproduction task, whether besides the activation of lateralized spatial codes, numerical processing modulates the mental representation of a horizontal spatial extension. Mis-estimations of length induced by Arabic numbers are interpreted in terms of a cognitive illusion, according to which the elaboration of magnitude information brings about an expansion or compression of the mental representation of spatial extension. These results support the hypothesis that visuo-spatial resources are involved in the representation of numerical magnitude.