Integrating novel dimensions to eliminate category exceptions: when more is less

Category learning can be characterized as a process of discovering the dimensions that represent stimuli efficiently and effectively. Categories that are overlapping when represented in 1 dimensionality may be separate in a higher dimensional cue set. The authors report 2 experiments in which participants were shown an additional cue after learning to use 2 imperfect cues. The results revealed that participants can integrate new information into their categorization cue set. The authors discovered wide individual differences, however, with many participants favoring simpler, but less accurate, cue sets. Some participants demonstrated the ability to discard information previously used when new, more accurate information was introduced. The categorization model RASHNL (J. K. Kruschke & M. K. Johansen, 1999) gave qualitatively accurate fits of the data.     

Working harder for less: Effect of incentive value on force of instrumental response in humans

The present article reports evidence from human subjects that high payoff for instrumental performance may cause reduced vigour of response compared to the vigour observed for lower payoffs. Vigour of response, as measured by force of pressing (Experiment 1) and number of fortune wheel turns (Experiment 2), was inversely related to payoffs, with higher vigour in the low payoff conditions. Experiment 2 further demonstrated this effect, regardless of whether or not payoff depended on performance. These findings are related to parallel animal data, and an analysis in terms of a learned incentive-effort hypothesis is offered. Experiment 3 presented support for this hypothesis. The results are argued to be of importance to the understanding of how reinforcers affect human instrumental performance.     

Recall accuracy and illusory memories: when more is less

In two experiments it was revealed that manipulations that increased recall of studied list items also increased false recall of theme-related, critical nonpresented words. In Experiment 1 subjects listened to a series of short word lists, each containing items associatively related to a theme, while engaging in either semantic or nonsemantic processing. On an immediate free recall test semantic processors demonstrated greater correct recall as well as more illusory memories of critical nonpresented items than nonsemantic processors. In Experiment 2, the short study lists were combined to form longer lists that were presented either blocked by theme or in a random presentation order. Retention interval was also varied as participants were tested either immediately, one week after, or three weeks after the study phase. Presenting the target items in a blocked, as opposed to random, format increased recall accuracy, but this was at the expense of a higher intrusion rate for theme-consistent items. Interestingly, the level of false memories was not affected by retention interval even though typical decrements in the recall of study items were observed over time. The results of these experiments highlight the persistence of the false memory effect, as well as pointing to several factors, primarily semantic processing, that may lead to the creation of false memories. Interpretations are offered within the theoretical frameworks of source monitoring and fuzzy trace theory.     

Rats learn to eat more to avoid hunger

Several recent experiments have provided evidence that the ingestion of a distinctive food by rats can be a learnt instrumental act as well as an associatively conditioned reaction. In the previous work, maintenance food was withheld for shorter and longer durations on different days following access to the training food. Extra eating before the longer fast was interpreted as avoidance of hunger. This interpretation was based on the evidence showing that extra eating as a result of classical conditioning comes from pairing food stimuli with the presence of little or no hunger because of repletion with energy nutrients. The theory that the extra eating arose from a response-depletion contingency was tested in the present experiment by training rats on only a long fast or only a short fast. Greater increase in intake was seen before the longer fast. The results also replicated previously seen cycles of increase, decrease, and renewed increase in putative deficit-avoidant eating over about three trials, indicating that the extra eating reduces the response-reinforcing hunger and that the consequent part-extinction restores reinforcement. The shape of the learning curve was consistent with these cycles occurring from the start of training, further supporting the view that the increase in food intake before a long delay in refeeding is hunger-reinforced instrumental behaviour.     

Suboptimal choice by dogs: when less is better than more

The less is more effect, an example of an affect heuristic, can be shown in humans when they give greater value to a set of six baseball cards in perfect condition, than to the same set of six perfect cards together with three additional cards each with some value but in fair condition. A similar effect has been reported in monkeys which will eat both grapes and cucumbers but prefer grapes, when they prefer a single grape over a single grape plus a slice of cucumber. In the present experiment, we tested the less is more effect with a nonprimate but social species, dogs. We used dogs that would eat a slice of carrot and a slice of cheese but preferred the cheese. When we then gave them a choice between a slice of cheese and a slice of cheese plus a slice of carrot, most dogs preferred the single slice of cheese. Thus, the less is more effect appears to occur in several species.     

Intuition beyond recognition: when less familiar events are liked more

In a laboratory experiment, we compare the relative impact of two possible determinants of intuitive evaluative judgments: ease of recognition and total value of prior encounters with a target. Participants encode daily return values of shares on the stock market while watching videotaped ads on the computer screen. This dual-task procedure ensures that participants subsequently lack relevant event memories and thus have to rely on their intuition when evaluating the targets. In the presentation, the share appearing least frequently produced the highest sum of returns. In contrast, the share appearing most frequently produced the lowest sum of returns. Evaluative judgments reveal a preference for the share with the highest sum of returns, although, as evident from recognition latencies, it was the one that was more difficult to recognize. The results provide evidence for the value-account model of implicit attitude formation (Betsch, Plessner, Schwieren, & Gütig, 2001), which predicts that intuitive evaluative judgments reflect the total value of prior encounters.     

Decisions beyond boundaries: when more information is processed faster than less

Bounded rationality models usually converge in claiming that decision time and the amount of computational steps needed to come to a decision are positively correlated. The empirical evidence for this claim is, however, equivocal. We conducted a study that tests this claim by adding and omitting information. We demonstrate that even an increase in information amount can yield a decrease in decision time if the added information increases coherence in the information set. Rather than being influenced by amount of information, decision time systematically increased with decreasing coherence. The results are discussed with reference to a parallel constraint satisfaction approach to decision making, which assumes that information integration is operated in an automatic, holistic manner.     

When less is more and when more is more: The mediating roles of capacity and speed in brain-behavior efficiency

An enduring enterprise of experimental psychology has been to account for individual differences in human performance. Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individual differences but this burgeoning literature has been characterized by inconsistent results. We argue that careful design and analysis of neuroimaging studies is required to separate individual differences in processing capacity from individual differences in processing speed to account for these differences in the literature. We utilized task designs which permitted separation of processing capacity influences on brain-behavior relationships from those related to processing speed. In one set of studies, participants performed verbal delayed-recognition tasks during blocked and event-related fMRI scanning. The results indicated that those participants with greater working memory (WM) capacity showed greater prefrontal cortical activity, strategically capitalized on the additional processing time available in the delay period, and evinced faster WM-retrieval rates than low-capacity participants. In another study, participants performed a digit-symbol substitution task (DSST) designed to minimize WM storage capacity requirements and maximize processing speed requirements during fMRI scanning. In some prefrontal cortical (PFC) brain regions, participants with faster processing speed showed less PFC activity than slower performers while in other PFC and parietal regions they showed greater activity. Regional-causality analysis indicated that PFC exerted more influence over other brain regions for slower than for faster individuals. These results support a model of neural efficiency in which individuals differ in the extent of direct processing links between neural nodes. One benefit of direct processing links may be a surplus of resources that maximize available capacity permitting fast and accurate performance.     

The neural consequences of semantic richness: when more comes to mind, less activation is observed

Some concepts have richer semantic representations than others. That is, when considering the meaning of concepts, subjects generate more information (more features, more associates) for some concepts than for others. This variability in semantic richness influences responses in speeded tasks that involve semantic processing, such as lexical decision and semantic categorization tasks. It has been suggested that concepts with richer semantic representations build stronger attractors in semantic space, allowing faster settling of activation patterns and thus faster responding. Using event-related functional magnetic resonance imaging, we examined the neural activation associated with semantic richness by contrasting activation for words with high and low numbers of associates in a semantic categorization task. Results were consistent with faster semantic settling for words with richer representations: Words with a low number of semantic associates produced more activation than words with a high number of semantic associates in a number of regions, including left inferior frontal and inferior temporal gyri.     

The believability of children and their interviewers' hearsay testimony: when less is more

Hearsay testimony from children's interviewers is increasingly common in sexual abuse trials, but little is known about its effects on juries. In 2 studies, the authors examined college students' perceptions of 3 types of hearsay testimony (an actual interview with a child or an adult interviewer providing either the gist of what that child had said or a verbatim account of the interview). Interviewers were rated as more accurate and truthful than the children. The interview was rated as higher quality, and children's statements, including their false statements, were sometimes rated as more believable in the interviewer gist hearsay condition. Mock jurors reacted differently to various types of hearsay testimony, and interviewer gist testimony may favor a child's case.     

The dynamics of daily events and well-being across cultures: when less is more

The authors examined cultural and individual differences in the relation between daily events and daily satisfaction. In a preliminary study, they established cross-cultural equivalence of 50 daily events. In the main study, participants in the United States, Korea, and Japan completed daily surveys on the 50 events and daily satisfaction for 21 days. The multilevel random coefficient model analyses showed that (a) the within-person association between positive events and daily satisfaction was significantly stronger among Asian American, Korean, and Japanese participants than among European American participants and (b) the within-person association between positive events and daily satisfaction was significantly weaker among individuals high in global life satisfaction than among those low in global life satisfaction. The findings demonstrate a weaker effect of positive events on daily well-being among individuals and cultures high in global well-being.     

Failure to obtain positive contrast when pigeons press a bar

In Experiment 1, two groups of pigeons were exposed to multiple variable-interval 1-min variable-interval 1-min schedules of reinforcement. The required response was a key peck for one group, and a foot press of a bar for the other. When the procedure was shifted to multiple variable-interval 1-min extinction, positive contrast occurred with pigeons that key pecked, whereas negative induction occurred with those that bar pressed. Moreover, the absence of contrast could not be ascribed to the lack of inhibition, since negative generalization gradients after bar press training were U-shaped in Experiment 2. The results are discussed in terms of possible relationships between positive contrast and the phenomenon of autoshaping.     

When less is more: Consumer aversion to unused utility

A series of experiments demonstrates that consumers exhibit aversion to waste during forward-looking purchase. These experiments further reveal that such behavior is driven by distaste for unused utility, a reaction that is shown to be distinct from an aversion to squandering money. Waste aversion is especially pronounced when consumers anticipate future consequences and deprivation is salient. In addition to demonstrating robustness across consumers and marketing contexts, the results also demonstrate how waste aversion can lead to self-defeating behavior in which consumers forego desired utility. Finally, the present research demonstrates and discusses the implications of waste aversion for a variety of marketing issues, including buy-rent markets, bundling, and the fundamental distinction between goods and services.     

Women seek more variety in rewards when closer to ovulation

We propose that women's increased generalized sensitivity to rewards during the fertile phase of the menstrual cycle causes them to seek more variety in rewards when they are in the fertile phase than when they are not in the fertile phase of the cycle. In Studies 1–3, across the reward domains of mating and hedonic food, we show that women seek more variety in rewards when closer to ovulation. Moreover, we provide support for the proposition that women's increased reward sensitivity during the fertile phase of the menstrual cycle causes their greater variety seeking. Specifically, in Study 3, we show that fertile women's greater variety seeking does not extend to non-rewards, such as non-hedonic food. Our findings suggest that behavioral effects of women's hormonal shifts during the menstrual cycle are not limited to the mating domain and may extend to a wide category of reward domains.     

People are more likely to be insincere when they are more likely to accidentally tell the truth

Although people lie often, and mostly for self-serving reasons, they do not lie as much as they could. The “fudge factor” hypothesis suggests that one reason for people not to lie is that they do not wish to self-identify as liars. Accordingly, self-serving lies should be more likely when they are less obvious to the liars themselves. Here we show that the likelihood of self-serving lies increases with the probability of accidentally telling the truth. Players in our game could transmit sincere or insincere recommendations to their competitors. In line with the fudge factor hypothesis, players lied when their beliefs were based on flimsy evidence and did not lie when their beliefs were based on solid evidence. This is the first demonstration of a new moral hypocrisy paradox: People are more likely to be insincere when they are more likely to accidentally tell the truth.     

When and how less is more: reply to Tharp and Pickering

In DeCaro et al. [DeCaro, M. S., Thomas, R. D., & Beilock, S. L. (2008). Individual differences in category learning: Sometimes less working memory capacity is better than more. Cognition, 107, 284-294] we demonstrated that sometimes less working memory (WM) has its advantages. The lower individuals’ WM, the faster they achieved success on an information-integration (II) category learning task adopted from Waldron and Ashby [Waldron, E. M., & Ashby, F. G. (2001). The effects of concurrent task interference on category learning: Evidence for multiple category learning systems. Psychonomic Bulletin & Review, 8, 168-176]. We attributed this success to the inability of lower WM individuals to employ explicit learning strategies heavily reliant on executive control. This in turn, we hypothesized, might push lower WM individuals to readily adopt procedural-based strategies thought to lead to success on the II task. Tharp and Pickering [Tharp, I. J., & Pickering, A. D. (2009). A note on DeCaro, Thomas, and Beilock (2008): Further data demonstrate complexities in the assessment of information-integration category learning. Cognition] recently questioned whether the II category learning task DeCaro et al. used really reflects procedural learning. In an effort to investigate Tharp and Pickering’s assertions with respect to individual differences in WM, we replicate and extend our previous work, in part by modeling participants’ response strategies during learning. We once again reveal that lower WM individuals demonstrate earlier II learning than their higher WM counterparts. However, we also show that low WM individuals’ initial success is not because of procedural-based responding. Instead, individuals lower in WM capacity perseverate in using simple rule-based strategies that circumvent heavy demands on WM while producing above-chance accuracy.     

When more is less: failure to compress discourse with re-telling in normal ageing

When young adults tell the same story repeatedly, their narratives become progressively more concise. Although impaired discourse production has been reliably demonstrated in the elderly, changes in narrative production with repetition have not been investigated in this cohort. Thirty young (aged 18-49 years, M=28.77, SD=9.73) and thirty elderly (aged 65+ years, M=73.57, SD=6.80) adults completed a discourse production task involving narrative construction using an eight-frame cartoon. Narratives were repeated 4 consecutive times. Variables analysed were narrative duration, word count and fluency (words/sec). For all variables the compression index for the elderly group was significantly lower than that for young participants. Further, compared to their younger counterparts, elderly adults were less able to improve the cohesion of their narratives with repetition. These findings suggest that the elderly have a reduced capacity to generate and refine discourse representations.     

Cheating more for less: Upward social comparisons motivate the poorly compensated to cheat

Intuitively, people should cheat more when cheating is more lucrative, but we find that the effect of performance-based pay-rates on dishonesty depends on how readily people can compare their pay-rate to that of others. In Experiment 1, participants were paid 5 cents or 25 cents per self-reported point in a trivia task, and half were aware that they could have received the alternative pay-rate. Lower pay-rates increased cheating when the prospect of a higher pay-rate was salient. Experiment 2 illustrates that this effect is driven by the ease with which poorly compensated participants can compare their pay to that of others who earn a higher pay-rate. Our results suggest that low pay-rates are, in and of themselves, unlikely to promote dishonesty. Instead, it is the salience of upward social comparisons that encourages the poorly compensated to cheat.     

How emotions expressed by adults’ faces affect the desire to eat liked and disliked foods in children compared to adults

The aim of this study was to determine whether or not pleasure, neutrality, and disgust expressed by eaters in photographs could affect the desire to eat food products to a greater extent in children than in adults. Children of 5 and 8 years of age, as well as adults, were presented with photographs of liked and disliked foods. These foods were presented either alone or with an eater who expressed three different emotions: pleasure, neutrality, or disgust. Results showed that, compared with food presented alone, food presented with a pleasant face increased the desire to eat disliked foods, particularly in children, and increased the desire to eat liked foods only in the 5‐year‐old children. In contrast, with a disgusted face, the desire to eat the liked foods decreased in all participants, although to a greater extent in children, while it had no effect on the desire to eat the disliked foods. Finally, food presented with a neutral face also increased and decreased the desire to eat disliked and liked foods, respectively, and in each case more for the 5‐year‐olds than for the older participants. In sum, the facial expressions of others influence the desire to eat liked and disliked foods and, to a greater extent, in younger children.     

Use of public information when foraging: effects of time available to sample foods

It has been proposed that use of socially acquired information by animals should increase as the time available for individual resource sampling decreases. We gave Norway rat “observers” either 2 or 5 h day^–1 to sample four foods. Three of these foods were relatively palatable, but protein-poor; the fourth was relatively unpalatable, but protein-rich. We found that observer rats that for 2 h day^–1 both sampled foods and interacted with demonstrators eating only the protein-rich food ate more of the protein-rich food than did observers that sampled for 2 h day^–1 but had no opportunity to interact with demonstrators. On the other hand, observer rats that could sample foods for 5 h day^–1 ate equal amounts of protein-rich food whether they interacted with a demonstrator fed protein-rich food or not. Subsequent analyses showed that the time available to observers to sample foods, rather than the opportunity to interact with demonstrators determined whether such interaction influenced observers’ food choices. The results are consistent with the hypothesis that animals increase their use of public information in response to temporal constraints on opportunities for resource sampling. Received: 22 December 1998 / Accepted after revision: 27 February 1999