End state copying by humans (Homo sapiens): implications for a comparative perspective on cumulative culture

It has been proposed that the uniqueness of human cumulative culture may be attributable to humans' greater orientation toward copying the process of behavior (imitation), as compared with the products (emulation), resulting in particularly high fidelity transmission. Following from previous work indicating that adult human participants can exhibit cumulative learning on the basis of product copying alone, we now investigate whether such learning involves high fidelity transmission. Eighty adult human (Homo sapiens) participants were presented with a task previously shown to elicit cumulative learning under experimental conditions, which involved building a tower from spaghetti and modeling clay. Each participant was shown two completed towers, ostensibly built by previous participants, but actually built to prespecified designs by the experimenter. This end state information was provided either in the form of photographs, or the presence of actual towers. High fidelity matching to these end states was apparent in both demonstration conditions, even for a design that was demonstrably suboptimal with regard to the goal of the task (maximizing tower height). We conclude that, although high fidelity transmission is likely to be implicated in cumulative culture, action copying is not always necessary for this to occur. Furthermore, since chimpanzees apparently copy behavioral processes and well as products, and also transmit behavior with high fidelity, the stark absence of unequivocal examples of cumulative culture in nonhumans may be attributable to factors other than imitative ability.     

The differential influences of positive affect,random reward,and performance-contingent reward on cognitive control

Growing evidence suggests that positive affect and reward have differential effects on cognitive control. So far, however, these effects have never been studied together. Here, the authors present one behavioral study investigating the influences of positive affect and reward (contingent and noncontingent) on proactive control. A modified version of the AX-continuous performance task, which has repeatedly been shown to be sensitive to reward and affect manipulations, was used. In a first phase, two experimental groups received either neutral or positive affective pictures before every trial. In a second phase, the two halves of a given affect group additionally received, respectively, performance-contingent or random rewards. The results replicated the typical affect effect, in terms of reduced proactive control under positive as compared to neutral affect. Also, the typical reward effects associated with increased proactive control were replicated. Most interestingly, performance-contingent reward counteracted the positive affect effect, whereas random reward mirrored that effect. In sum, this study provides first evidence that performance-contingent reward, on the one hand, and positive affect and performance-noncontingent reward, on the other hand, have oppositional effects on cognitive control: Only performance-contingent reward showed a motivational effect in terms of a strategy shift toward increased proactive control, whereas positive affect alone and performance-noncontingent reward reduced proactive control. Moreover, the integrative design of this study revealed the vulnerability of positive affect effects to motivational manipulations. The results are discussed with respect to current neuroscientific theories of the effects of dopamine on affect, reward, and cognitive control.     

I don’t care about others’ approval: Dysphoric individuals show reduced effort mobilization for obtaining a social reward

Past research on reduced reward responsiveness in depression and dysphoria has mainly focused on monetary rewards. However, social rewards are important motivators and might be especially impaired in depression. The present study tested the hypothesis that nondysphoric individuals would mobilize more effort during a memory task without a clear performance standard when anticipating social approval for good performance. In contrast, dysphoric individuals were expected to be less sensitive to this reward and to mobilize less effort. Effort mobilization in this 2 (dysphoric vs. nondysphoric) × 2 (no reward vs. social approval) between-persons study was operationalized by participants’ cardiovascular reactivity. Results confirmed that nondysphorics had higher reactivity of systolic blood pressure, diastolic blood pressure, and heart rate when expecting to enter their name in the alleged “best list”, whereas dysphorics had lower cardiovascular reactivity. The present study expands evidence for reduced reward responsiveness in depression and dysphoria from an effort mobilization perspective by demonstrating reduced effort-related cardiovascular reactivity to social rewards.     

Automatic activation of attribute knowledge in heuristic inference from memory

In memory-based decision making, people often rely on simple heuristics such as take-the-best (TTB; Gigerenzer & Goldstein, Psychological Review, 103, 650–669, 1996), which processes information about the alternatives sequentially and stops processing as soon as a decision can be made. In this article, we examine the memory processes associated with TTB—in particular, to what degree the selective memory retrieval of relevant information required by TTB is accompanied by automatic activation of associated but irrelevant information. To address this question, we studied the fan effect (Anderson, Cognitive Psychology, 6, 451–474, 1974), which is assumed to arise from automatic spread of activation, in inferences from memory. Participants were instructed to use TTB when making decisions about objects on the basis of previously memorized attribute information. Both the number of attributes required by TTB and the number of attributes associated with an object (i.e., fan level) were manipulated. As it turned out, response times and the correct execution of TTB were a function not only of the number of required attributes, but also of the number of associated attributes. This suggests that information that TTB “ignores” is nevertheless activated in memory.     

The Coping Competence Questionnaire: A measure of resilience to helplessness and depression

Based on helplessness/hopelessness theories of depression, the 12-item Coping Competence Questionnaire (CCQ) was designed to assess resilience against helplessness and depression. Evidence from a study involving 2,224 participants indicates that the CCQ is highly reliable, stable over a 1-month period, unidimensional, and internally valid. The CCQ converged negatively with measures of depression, neuroticism, and stress reaction and showed discriminant validity with a variety of other personality constructs. Compared to a measure of attributional style, the CCQ proved to be a superior predictor of depressed mood. Path models support the assumption that the CCQ buffers the effects of stress and negative life events on depressed mood and that dysfunctional coping mediates the effects of coping competence deficits on depression.     

Lack of Inhibition: A Motivational Deficit in Children With Attention Deficit/Hyperactivity Disorder and Children With Traumatic Brain Injury*

Recent research has demonstrated that both brain-injured children and children with attention deficit/hyperactivity disorder (ADHD) suffer from response inhibition deficits. To investigate whether these deficits can be influenced by motivational factors, the stop-signal task was performed with and without reward contingencies for successful inhibition. Three groups of children between 8 and 12 years of age, participated in the study: 31 children with ADHD, 37 with traumatic brain injuries (TBI), and 26 normal controls. Results indicated that, although all groups showed comparable learning effects, reward contingencies had different effects on the groups. Whereas the performance of children with ADHD under reward contingencies were brought up to the performance level of normal controls, rewards were found less effective at improving response inhibition in children with TBI. The results further support a motivational/energetic explanation of the inhibitory deficit in children with ADHD, and of a primary response inhibition deficit due to structural brain damage in children with TBI.     

Andromeda Freed From Her Chains

Minds for the Making: The Role of Science in American Education, 1750–1990, by Scott L. Montgomery, New York: The Guilford Press, 1994, pb, $18.95.     

Memory for actions: Item and relational information in categorized lists

Enacting action phrases in subject-performed tasks (SPTs) leads to better free recall than hearing or reading the same materials in verbal tasks (VTs). This enactment effect is usually explained by better item-specific information in SPTs than in VTs. The role of relational information is controversial. In the present paper, we will take the multiple recall approach to study the role of item and relational information in memory for actions by computing the number of item gains and the number of item losses over trials. This approach has previously been applied to lists of unrelated action phrases. We applied it to categorically related lists, also allowing a measure of relational information by clustering scores. It was found that SPTs produced more item gains than VTs. This finding confirmed the assumption that SPTs provide better item-specific information than VTs. The number of item losses did not differ between VTs and SPTs. This finding suggests that relational information is equally provided by VTs and SPTs. However, the organizational scores showed a more differentiated picture. Clustering was greater in SPTs than in VTs with randomly presented lists, but not with blocked lists. We suggested that these results, as well as other findings from the literature, could be explained by distinguishing automatic and strategic processes and the types of item associations that are addressed by these processes.     

Differential relational encoding of categorical information in memory for action events

Memory for action phrases is better if the actions are enacted in subject-performed tasks (SPTs) than if they are only listened to in verbal tasks (VTs). This effect is ascribed to better item-specific encoding of SPTs than of VTs. The role of interitem relational information is controversial, and the findings of clustering with categorically structured lists are inconsistent (see Engelkamp, 1998). The present study contributes to clarifying these effects by demonstrating that intentional relational encoding can be used more efficiently in VTs than in SPTs and influences the degree of clustering. If the list structure is not obvious, inducing intentional encoding by presenting the category labels prior to list presentation and asking subjects to use this preinformation increases clustering in VTs but not in SPTs. Without preinformation, clustering scores of VTs and SPTs did not differ, with preinformation, clustering of VTs was stronger than that of SPTs. The authors suggest how the inconsistent findings with regard to clustering effects can be explained.     

The item-order hypothesis reconsidered: The role of order information in free recall

According to the item-order approach of free recall, in pure short lists the free recall of unrelated items is organized according to their order of presentation in the study list. The approach was applied in the present study to experimenter-performed tasks (EPTs) and subject-performed tasks (SPTs). It claims that EPTs provide better serial order information than SPTs. Consequently, free recall of EPTs should be more organized along the presentation order of the items than the free recall of SPTs. In three experiments, some specific aspects of this approach were studied. Firstly, it was demonstrated that serial retrieval is not strongly used spontaneously and that its use is overestimated in the literature because it is usually evoked by an order reconstruction test which follows free recall testing. Secondly, a serial retrieval strategy in free recall can be encouraged by explicit instructions. Finally, the present experiments showed that a serial output strategy alone does not allow one to predict performance in free recall. The implications of these findings for the item-order approach will be discussed.