What you don’t know won’t hurt me: Costly (but quiet) exit in dictator games

We used simple economic games to examine pro-social behavior and the lengths that people will take to avoid engaging in it. Over two studies, we found that about one-third of participants were willing to “exit” a $10 dictator game and take $9 instead. The exit option left the receiver nothing, but also ensured that the receiver never knew that a dictator game was to be played. Because most social utility models are defined over monetary outcomes, they cannot explain choosing the ($9, $0) exit outcome over the dominating $10 dictator game, since the game includes outcomes of ($10, $0) and ($9, $1). We also studied exiting using a “private” dictator game. In the private game, the receiver never knew about the game or from where any money was received. Gifts in this game were added innocuously to a payment for a separate task. Almost no dictators exited from the private game, indicating that receivers’ beliefs are the key factor in the decision to exit. When, as in the private game, the receivers’ beliefs and expectations cannot be manipulated by exit, exit is seldom taken. We conclude that giving often reflects a desire not to violate others’ expectations rather than a concern for others’ welfare per se. We discuss the implications of our results for understanding ethical decisions and for testing and modeling social preferences. An adequate specification of social preferences should include “psychological” payoffs that directly incorporate beliefs about actions into the utility function.     

Effortful Control and Interpersonal Behavior in Daily Life

The Cognitive-Affective Processing System (CAPS) was used to examine effortful control (EC) as a moderator of daily interpersonal behavior. Participants (N = 240) were nonclinical young adults who completed a 7-day event-contingent experience sampling study of interpersonal perception and affect. Multilevel linear models indicated that EC moderated within-person covariation of interpersonal warmth and affect activation; high EC individuals reported greater momentary warm behaviors when perceiving others as affectively activated. EC also amplified between-person covariation of interpersonal warmth between self and others; high EC individuals generally responded to perceptions of another's warmth with a greater degree of warm behavior. Varying levels of EC predict responses to interpersonal perceptions and affect in daily life, suggesting an important dimension for interpersonal functioning.     

The Influence of Thought Suppression and Cognitive Load on Intrusions and Memory Processes Following an Analogue Stressor

Ironic Process Theory and the role of thought suppression have been used in part to explain the phenomenon of intrusive memories in various disorders, including posttraumatic stress disorder. How thought suppression interacts with other cognitive processes believed to be instrumental in the development of traumatic intrusive memory is unclear. In an analogue study, thought suppression and cognitive processing was manipulated in 4 experimental groups after participants (n = 80) viewed a trauma film. The impact of suppression was examined in relation to self-reported intrusive experiences as well as via more objective methods (word stem and dot probe tasks) to assess potential preferential encoding of negative material. Cognitive load appeared to undermine thought suppression ability, with these participants experiencing more intrusions over the week relative to participants in all other conditions. This group also showed greater priming to negative film-related words, and both suppression groups demonstrated enhanced memory for film-related content on recognition testing. Thought suppression mediated the relationship between negative interpretations of initial intrusions and later intrusions experienced over the week. The findings are discussed in the context of ironic process theory and cognitive models of posttraumatic stress.     

Imaginability,morality, and fictional truth: dissolving the puzzle of ‘imaginative resistance’

This paper argues that there is no genuine puzzle of ‘imaginative resistance’. In part 1 of the paper I argue that the imaginability of fictional propositions is relative to a range of different factors including the ‘thickness’ of certain concepts, and certain pre-theoretical and theoretical commitments. I suggest that those holding realist moral commitments may be more susceptible to resistance and inability than those holding non-realist commitments, and that it is such realist commitments that ultimately motivate the problem. However, I argue that the relativity of imaginability is not a particularly puzzling feature of imagination. In part 2, I claim that it is the so-called ‘alethic’ puzzle, concerning fictional truth, which generates a real puzzle about imaginative resistance. However, I argue that the alethic puzzle itself depends on certain realist assumptions about the nature of fictional truth which are implausible and should be rejected in favour of an interpretive view of fictional truth. Once this is done, I contend, it becomes evident that the supposed problem of imaginative resistance as it has hitherto been discussed in the literature is not puzzling at all.

Persistent up-regulation of polyribosomes at synapses during long-term memory,reconsolidation, and extinction of associative memory

Local protein synthesis at synapses can provide a rapid supply of proteins to support synaptic changes during consolidation of new memories, but its role in the maintenance or updating of established memories is unknown. Consolidation requires new protein synthesis in the period immediately following learning, whereas established memories are resistant to protein synthesis inhibitors. We have previously reported that polyribosomes are up-regulated in the lateral amygdala (LA) during consolidation of aversive-cued Pavlovian conditioning. In this study, we used serial section electron microscopy reconstructions to determine whether the distribution of dendritic polyribosomes returns to baseline during the long-term memory phase. Relative to control groups, long-term memory was associated with up-regulation of polyribosomes throughout dendrites, including in dendritic spines of all sizes. Retrieval of a consolidated memory by presentation of a small number of cues induces a new, transient requirement for protein synthesis to maintain the memory, while presentation of a large number of cues results in extinction learning, forming a new memory. One hour after retrieval or extinction training, the distribution of dendritic polyribosomes was similar except in the smallest spines, which had more polyribosomes in the extinction group. Our results demonstrate that the effects of learning on dendritic polyribosomes are not restricted to the transient translation-dependent phase of memory formation. Cued Pavlovian conditioning induces persistent synapse strengthening in the LA that is not reversed by retrieval or extinction, and dendritic polyribosomes may therefore correlate generally with synapse strength as opposed to recent activity or transient translational processes.

The formation of long-term memory involves a consolidation phase in the period immediately after learning, during which new proteins are required to stabilize learning-induced synapse remodeling (Davis and Squire 1984; Mayford et al. 2012; Rosenberg et al. 2014; Segal 2017). There is evidence that local protein synthesis in dendrites is essential for consolidation of long-term memory and related forms of synaptic plasticity (Holt and Schuman 2013), but its exact role is not well understood. Dendritic translation can supply new proteins to synapses rapidly, and potentially with synapse-specific spatial precision. Thousands of mRNAs have been identified in dendrites, many of which encode synaptic proteins (Poon et al. 2006; Zhong et al. 2006; Cajigas et al. 2012; Tushev et al. 2018; Middleton et al. 2019), and mRNA is present in dendritic spines (Tiruchinapalli et al. 2003; Hafner et al. 2019). The ability of dendritic mRNAs to remain dormant until they are unmasked by synaptic activity (Doyle and Kiebler 2011; Buxbaum et al. 2014; Hutten et al. 2014) provides a mechanism for rapid and targeted translation at synapses. Synaptic activity during learning triggers a transient up-regulation of new synaptic proteins in dendrites (Redondo and Morris 2011; Moncada et al. 2015), and the spatiotemporal constraints on these new proteins strongly suggest that they are translated locally (Sajikumar et al. 2007; Doyle and Kiebler 2011). We have previously found by serial section transmission electron microscopy (ssTEM) volume reconstruction that polyribosomes and translation factors are up-regulated in dendritic spines in the rat lateral amygdala (LA) 1 h after cued aversive Pavlovian conditioning (Ostroff et al. 2010, 2017; Gindina et al. 2021). These polyribosomes presumably represent translation supporting consolidation, but no studies have addressed whether dendritic translation remains elevated or returns to baseline in the long-term memory phase.Cued aversive Pavlovian conditioning, also referred to as fear or threat conditioning, is an extensively studied learning paradigm in which a sensory cue is paired with an unpleasant stimulus—typically an auditory cue with a mild shock—to create an associative memory between the two (LeDoux 2000; Maren 2001). There is strong evidence that this memory is mediated by protein synthesis-dependent strengthening of LA synapses during a short window after learning. Enhanced synaptic transmission is observed in the LA after conditioning (McKernan and Shinnick-Gallagher 1997; Rogan et al. 1997; Sah et al. 2008), and consolidation requires protein synthesis in the LA immediately after training, but not 6 or 24 h later (Nader et al. 2000; Schafe and LeDoux 2000; Maren et al. 2003). The extracellular signal-regulated/mitogen-activated protein kinase (ERK/MAPK), which regulates translation (Kelleher et al. 2004), is transiently phosphorylated in the LA 1 h after learning, and this phosphorylation is required for both memory consolidation (Schafe et al. 2000) and synaptic plasticity in the LA (Huang et al. 2000; Schafe et al. 2008).Although dormant long-term memories are stable, retrieval induces a new labile phase called reconsolidation, during which the memory can be updated, weakened, or strengthened (Dudai 2012). As in consolidation, postretrieval inhibition of protein synthesis or ERK/MAPK phosphorylation in the LA impairs reconsolidation of the memory and associated synaptic plasticity (Nader et al. 2000; Duvarci et al. 2005; Doyere et al. 2007). A transient supply of necessary new proteins is available to synapses during reconsolidation (Orlandi et al. 2020), but whether these proteins are synthesized in dendrites is unknown. Both consolidation and reconsolidation are impaired by broad protein synthesis inhibitors, and there is substantial evidence that consolidation requires translation initiation, the step in which polyribosomes are formed (Gkogkas et al. 2010; Santini et al. 2014). Interestingly, one study found that inhibition of the predominant initiation process impaired consolidation but not reconsolidation, suggesting that the role of translation differs between the two processes (Hoeffer et al. 2011). Since polyribosomes can be stalled for later reactivation (Richter and Coller 2015), reconsolidation could rely on translation of pre-existing polyribosomes.Reconsolidation is triggered by a small number of retrieval cues, but retrieval with a large number of cues induces extinction learning, in which the cue loses its ability to elicit defensive responses (Myers and Davis 2007). There is ample evidence that plasticity important for extinction occurs in the basolateral amygdala (BLA; which includes the LA), though it is unclear exactly how this relates to the original memory trace in the dorsal LA (Bouton et al. 2021). For instance, consolidation of extinction is impaired by pretraining systemic inhibition of protein synthesis (Suzuki et al. 2004) and by pretraining inhibition of protein synthesis or ERK/MAPK in the BLA (Lin et al. 2003c; Herry et al. 2006). However, the Lin et al. (2003c) study measured the effects of protein synthesis inhibition in the BLA 30 min after extinction training, which is typically thought to reflect short-term memory. Subsequent work by another group found that postextinction training inhibition of protein synthesis impaired reconsolidation, making it difficult to assess the effects on extinction consolidation (Duvarci et al. 2006). There are also ongoing debates about the relative contribution of “erasure” versus “new learning” processes in extinction. Evidence that protein synthesis-dependent depotentiation of CS inputs to the LA contributes to extinction suggests up-regulation of polyribosomes in the LA pyramidal cells storing the original trace (Lin et al. 2003a,b,c; Kim et al. 2009). However, up-regulation of polyribosomes is also possible if extinction plasticity occurs in other cells or regions of the brain, as repeated retrieval trials may strongly trigger reconsolidation processes. Complicating things further, it appears that extinction can halt reconsolidation (Suzuki et al. 2004).To investigate the dynamics of local translation in the context of an established memory, we used ssTEM to quantify dendritic polyribosome distribution in the LA during the long-term memory phase of Pavlovian conditioning, reconsolidation, and consolidation of extinction. We hypothesized that polyribosomes would not be up-regulated in the long-term memory condition relative to controls, since memory maintenance is resistant to protein synthesis inhibition at this time point. We also hypothesized that both retrieval and extinction would induce up-regulation of polyribosomes, but in different patterns; for example, reconsolidation processes could be reflected in polyribosomes near large synapses, but extinction could result in loss of these synapses and perhaps more generalized polyribosome distribution.     

Odor quality: Discrimination versus free and cued identification

Eighty-two adults, ranging in age from young to elderly, performed odor-quality discrimination and both free and cued identification on six odorants presented at two intensity levels. The odorants simulated the real-world substances banana, licorice, cherry/almond, wintergreen, clove, and lemon. Performance on all three tasks declined with age, but improved with stimulus intensity. Performance at discrimination benefited from the mere availability of the six names during testing. Performance in cued identification far exceeded that in free identification and, for young and middle-aged adults, fell close to that for discrimination. For elderly adults, however, performance in cued identification fell substantially below that in discrimination. Although not entirely free of cognitive influences, discrimination seems to offer particularly clear resolution of alterations in olfactory functioning.     

Agonistic sensory effects of airborne chemicals in mixtures: Odor, nasal pungency, and eye irritation

Threshold responses of odor, nasal pungency (irritation), and eye irritation were measured for single chemicals (1-propanol, 1-hexanol, ethyl acetate, heptyl acetate, 2-pentanone, 2-heptanone, toluene, ethyl benzene, and propyl benzene) and mixtures of them (two three-component mixtures, two sixcomponent mixtures, and one nine-component mixture). Nasal pungency was measured in subjects lacking a functional sense of smell (i.e., anosmics) to avoid interference from olfaction. Various degrees of stimulus agonism (additive effects) were observed for each of the three sensory channels when testing mixtures. As the number of components and the lipophilicity of such components in the mixtures increased, so did the degree of agonism. Synergistic stimulus agonism characterized the eyeirritation response for the most complex (the nine-component) and the most lipophilic (one of the sixcomponent) mixtures. Physicochemical properties play a large role in the determination of sensitivity to airborne chemicals, particularly to their ability to evoke irritation. While this has revealed itself previously with respect to single chemicals, it seems to have relevance to mixtures as well.     

Sensory and semantic factors in recognition memory for odors and graphic stimuli: elderly versus young persons

In four experiments, young (18-26 years, M = 21) and elderly (over 65 years, M = 72) people were compared for recognition memory of (a) graphic stimuli (faces of presidents and vice presidents, engineering symbols, and free forms) and (b) everyday odors. On graphic stimuli, the elderly consistently matched the young, but on odors the performance of the elderly was worse. Their poorer olfactory performance was observed after only 26 s, but became truly marked after 1 hr or more. Somewhere between 1 hr and 2 weeks, their odor performance fell to chance, but their graphic performance remained well above chance. Although the young did forget both graphic and odor materials progressively, their performance always stayed above chance over a 6-month period. Experiments 1 and 2 revealed that the elderly are less sensitive to odors than the young (with thresholds about 10-fold higher), which may explain, in part, their poorer olfactory memory performance. Knowledge that the subjects brought to the tasks by way of familiarity with and ability to name odors and faces played a positive role in recognition memory. Because of this positive role, together with the negative role played by verbal distraction, we conclude that odor recognition memory depends, perhaps heavily, on semantic processing. Impaired semantic processing may result even when odors are simply rendered desaturated, or pastel because of the weakening of olfactory sensitivity with aging.     

Odor magnitude: Coarse vs. fine grain

Despite a dismal reputation, olfaction’s resolving power actually appears to be keen, especially when the contaminating influence of noise in the stimulus is discounted from psychophysical performance. In a previous investigation, subjects were able to resolve a change of 4% in the concentration of butyl alcohol. In the present experiment, these same subjects resolved a change of 9% in the concentration of amyl butyrate. The data imply that resolving power varies among odorants. The growth of odor intensity assessed by magnitude estimations of easily discriminable (i.e., grossly different) concentrations also varies among odorants. These observations prompt the question: Does an odorant for which resolution is relatively difficult lead to slower growth of perceived intensity with concentration than an odorant for which resolution is easy? In a scaling experiment, amyl butyrate indeed led to slower growth of intensity than butyl alcohol. Nevertheless, amyl alcohol, which permitted poorer resolution than butyl alcohol, led to approximately the same rate of growth as butyl alcohol. Accordingly, growth of odor intensity with concentration may correlate only weakly with resolving power.