Scene memory is more detailed than you think: the role of categories in visual long-term memory

Observers can store thousands of object images in visual long-term memory with high fidelity, but the fidelity of scene representations in long-term memory is not known. Here, we probed scene-representation fidelity by varying the number of studied exemplars in different scene categories and testing memory using exemplar-level foils. Observers viewed thousands of scenes over 5.5 hr and then completed a series of forced-choice tests. Memory performance was high, even with up to 64 scenes from the same category in memory. Moreover, there was only a 2% decrease in accuracy for each doubling of the number of studied scene exemplars. Surprisingly, this degree of categorical interference was similar to the degree previously demonstrated for object memory. Thus, although scenes have often been defined as a superset of objects, our results suggest that scenes and objects may be entities at a similar level of abstraction in visual long-term memory.     

Epistemic Virtues and Virtue Epistemology

This paper introduces the articles in this volume, and offers an overview of each piece.     

Honoring Teachers for Their Vocation and Potential

Abstract. One goal of the Wabash Center is to honor teachers for their potential, and hospitality has been a primary means to that end. A lesson learned is that the intention and effort to honor teachers create contexts for meaningful discussions, creative learning, and personal renewal of those engaged in workshops and consultations. The lesson is valuable for those engaged in all forms of adult learning, especially in colleges and theological schools.     

Safety behaviours preserve threat beliefs: Protection from extinction of human fear conditioning by an avoidance response

A laboratory autonomic conditioning procedure was used to establish fear conditioning in human participants by pairing neutral stimuli with electric shock. Participants were also trained to make a button-press response to avoid shock. A target fear stimulus was then extinguished by presenting it without shock. The experimental group was given the opportunity to make the avoidance response during extinction whereas the control group was not. When the fear stimulus was tested without the response available, the control group showed normal extinction of both shock expectancy ratings and skin conductance responses, but the experimental group showed “protection from extinction”: they continued to give high expectancy ratings and strong skin conductance responses. We interpret this effect as analogous to the role of within-situation safety behaviours in preserving threat beliefs during exposure therapy for anxiety disorders. The results support a cognitive account of learning and anxiety. The procedure provides a potential laboratory model for further examination of the cognitive and neural mechanisms underlying anxiety and its reduction.     

Reasons and Rational Motivational Access

Practical Internalism holds that an agent's reasons for acting are entirely determined by his rational desires. This account is thought to be preferable to externalism, on the grounds that internalism alone can guarantee that agents have 'rational motivational access' (RMA) to their reasons. Rachel Cohon has recently argued that (i) internalism fails to ensure this, and (ii) an externalist account, akin to relativism, can guarantee RMA. I suggest that both of these claims are mistaken. I argue that relativism is best understood as an internalist theory, and claim that one version of internalism can therefore guarantee RMA.     

Hierarchical semantics for relevant logics

This paper was presented to the 1990 meeting of the Australasian Association for Logic held at the University of Sydney, and I thank those present for helpful comments made.     

Comorbidity of anxiety and depression in children and adolescents.

Anxiety and depression in children and adolescents are reviewed, including differential diagnosis, assessment of symptoms, family history data, developmental features, and clinical correlates. Findings indicate that 15.9% to 61.9% of children identified as anxious or depressed have comorbid anxiety and depressive disorders and that measures of anxiety and depression are highly correlated. Family history data are inconclusive. Differences emerged among children with anxiety, depression, or both disorders. Anxious children were distinguishable from the other 2 groups in that they showed less depressive symptomatology and tended to be younger. The concurrently depressed and anxious group tended to be older and more symptomatic. In this group, the anxiety symptoms tended to predate the depressive symptoms. Findings are discussed in the context of a proposed developmental sequence.     

Motivational effects of smoked marijuana: behavioral contingencies and low-probability activities.

Six adult male research volunteers, in two groups of 3 subjects each, lived in a residential laboratory for 15 days. All contact with the experimenters was through a networked computer system, and subjects' behavior was monitored continuously and recorded. During the first part of each day, they were allowed to socialize. Two cigarettes containing active marijuana (2.7% delta 9-THC) or placebo were smoked during the private work period and the period of access to social activities. Three-day contingency conditions requiring subjects to engage in a low-probability work activity (instrumental activity) in order to earn time that could be spent engaging in a high-probability work activity (contingent activity) were programmed during periods of placebo and active-marijuana smoking. During placebo administration, the contingency requirement reliably increased the amount of time that subjects spent engaged in the low-probability instrumental activity and decreased the time spent engaged in the high-probability activity. During active-marijuana administration, however, the increases in instrumental activity were consistently larger than observed under placebo conditions. The decreases in contingent activity were similar to those seen under placebo conditions. Smoking active marijuana was thus observed to produce increments in instrumental activity under motivational conditions involving contingencies for "work activities."     

Context and companion's behavior as determinants of cooperation and competition in school-age children

Information about the social context and a companion's actions were studied as determinants of cooperation and competition in middle childhood. In Experiment 1, first-, third-, and fifth-grade children were told that they would play a board game with another same-age, same-sex child (actually a bogus companion). The experimenter's instructions established shared rewards or winner-take-all as outcome conditions. Preprogrammed responses—100% cooperative or 100% competitive—provided information about the companion's actions. Results revealed that the companion's responses alone determined cooperation and competition among the first graders. Third graders used both types of information. Fifth graders, however, demonstrated a bias to respond cooperatively whenever a cooperative cue was present. In Experiment 2, first-grade subjects were given extra rehearsal of the game strategies, a scorekeeping procedure for use during the game, or a combination of the two. Results indicated that, under these conditions, younger subjects were able to use the instructions about reward distribution as well as the companion's actions in guiding their social behavior.