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Autistic traits are widely thought to operate along a continuum. A taxometric analysis of Adult Autism Spectrum Quotient data was conducted to test this assumption, finding little support but identifying a high severity taxon. To understand this further, latent class and latent profile models were estimated that indicated the presence of six distinct subtypes: one with little probability of endorsing any autistic traits, one engaging in "systemising" behaviours, three groups endorsing multiple components of Wing and Gould's autistic triad, and a group similar in size and profile to the taxon previously identified. These analyses suggest the AQ (and potentially by extension autistic traits) have a categorical structure. These findings have important implications for the analysis and interpretation of AQ data.

We report the results of a human fMRI experiment investigating the influence of context upon value judgement. Trials were separated into high and low value blocks such that it is possible to investigate the effect of a change in surrounding trials upon the encoding of financial value. The ventral striatum was dependent upon "local context", with its activity representing the current stimulus' relative value compared only to items in the current block. Conversely the ventral medial Pre-Frontal Cortex and Anterior Cingulate Cortex respond independently of block but also do not represent the absolute values of stimuli. Our use of stimuli values with a non-linear distribution allow us to identify the pattern as representing rank order. This has wide reaching implications for research on neuroeconomics, decision making and reward representation, showing that financial value is not explicitly represented within the brain. (Contains 6 tables and 4 figures.)

The Iowa Gambling Task (Bechara, Damasio, Damasio, & Anderson, 1994) has become widely used as a laboratory test of "real-life" decision-making. However, aspects of its administration that have been varied by researchers may differentially affect performance and the conclusions researchers can draw. Some researchers have used facsimile money reinforcers while others have used real money reinforcers. More importantly, the instructions participants receive have also been varied. While no differences have been reported in performance dependent on reinforcer type, no previous comparison of participants' instructions has been conducted. This is despite one set of instructions giving participants a clear hint about the nature of the task. Additionally, in previous research one set of instructions have not been used exclusively with one reinforcer type making any differential or cumulative effects of these factors difficult to interpret. The present study compared the effects of instruction and reinforcer type on IGT performance. When participants received instructions without a hint performance was affected by reinforcer type. This was not the case when the instructions included a hint. In a second IGT session performance was improved in participants who had received the hint instructions compared with those who had not.

We outline three attempts to replicate experiments that reported priming effects on time preferences measured by delay discounting. Experiment 1 tested the claim that images of poverty prime impulsive choice in people from less affluent backgrounds compared with people from more affluent backgrounds. Experiment 2 tested the claim that mortality salience—thinking about death—primes people to place more value on the future than people who thought about dental surgery. Experiment 3 tested the claim that an episodic foresight manipulation primes greater discounting than no episodic foresight. Experiments 1 and 2 failed to replicate the effects of priming on discount rates. Experiment 3 was a successful and very close replication of the effect of episodic foresight on discount rates. [ABSTRACT FROM AUTHOR]

Humans are characterized by an unusual level of prosociality. Despite this, considerable indirect evidence suggests that biological kinship plays an important role in altruistic behaviour. All previous reports of the influence of kin selection on human altruism have, however, used correlational (rather than experimental) designs, or imposed only a hypothetical or negligible time cost on participants. Since these research designs fail either to control for confounding variables or to meet the criteria required as a test of Hamilton's rule for kin selection (that the altruist pays a true cost), they fail to establish unequivocally whether kin selection plays a role. We show that individuals from two different cultures behave in accordance with Hamilton's rule by acting more altruistically (imposing a higher physical cost upon themselves) towards more closely related individuals. Three possible sources of confound were ruled out: generational effects, sexual attraction and reciprocity. Performance on the task however did not exhibit a perfect linear relationship with relatedness, which might reflect either the intrusion of other variables (e.g. cultural differences in the way kinship is costed) or that our behavioural measure is insufficiently sensitive to fine-tuned differences in the way individuals view their social world. These findings provide the first unequivocal experimental evidence that kinship plays a role in moderating altruistic behaviour. Kinship thus represents a baseline against which individuals pitch other criteria (including reciprocity, prosociality, obligation and a moral sense) when deciding how to behave towards others., Recent research, using small-scale experiments based on standard game formats from economics, has shown that people often apply criteria of fairness to social interactions, accede to social pressure and engage [...]

Preference reversals are a well-documented example of suboptimal decision making. Typical preference reversals experiments have involved monetary bets presented in probability format. Research on other examples of decision making have shown that irrational or suboptimal choices are diminished or eliminated entirely when the probabilities are presented as relative frequencies (e.g., Gigerenzer & Hoffrage, 1995). The aim of the present experiment was to determine if the way in which information is presented to participants affects participants' preferences. When the options were presented in the standard probability format 59% of participants' preferences were reversed. However, reversals were significantly decreased in the frequency format group, with only 40% of participants' responses being inconsistent. Although preference reversals were not eliminated when the gambles were presented as frequencies they were significantly diminished and may not be such a robust example of irrational decision making after all.

In this article, the authors propose that both implicit memory and implicit learning phenomena can be explained by a common set of principles, in particular via participants' strategic use of recollective and fluency heuristics. In a series of experiments, it was demonstrated that manipulating processing fluency had an impact on classification decisions in an artificial grammar learning task (Experiments 1, 2, 4, and 7), showing that participants were using a fluency heuristic. Under identical conditions, however, this manipulation had no effect on recognition decisions (Experiments 3 and 5), consistent with a greater default reliance on recollection. Most significant, the authors also showed that a fluency effect can be induced in recognition (Experiments 4-6) and can be eliminated in classification (Experiment 7).