Memory for two stimulus-response items in pigeons

Six pigeons served in a discrete-trial experiment on short-term memory. Combinations of three key positions and two ordinal positions, yielding six possible sequences of stimulus-response pairs, were used as lists of items. A retention interval separated list presentation from the test phase in which two (for Group 1) or three (for Group 2) keys were illuminated with either red or green light. A reinforcer was delivered if a subject pecked the key of the first item on a red trial and the key of the second item on a green trial. When the retention interval was lengthened from one to five or nine seconds, a systematic loss of stimulus control resulted. Lengthening the interval between items from one to eight seconds had a much smaller effect for the birds in Group 1, whereas a systematic loss of stimulus control was found in red trials for the birds in Group 2. The functional relations between choice accuracy and delay provided an empirical basis for analysis of what relations among temporal events can become discriminative stimuli.     

Memory for individual items is related to nonreinforced preference change

It is commonly assumed that memories contribute to value-based decisions. Nevertheless, most theories of value-based decision-making do not account for memory influences on choice. Recently, new interest has emerged in the interactions between these two fundamental processes, mainly using reinforcement-based paradigms. Here, we aimed to study the role memory processes play in preference change following the nonreinforced cue-approach training (CAT) paradigm. In CAT, the mere association of cued items with a speeded motor response influences choices. Previous studies with this paradigm showed that a single training session induces a long-lasting effect of enhanced preferences for high-value trained stimuli, that is maintained for several months. We hypothesized that CAT increases memory of trained items, leading to enhanced accessibility of their positive associative memories and in turn to preference changes. In two preregistered experiments, we found evidence that memory is enhanced for trained items and that better memory is correlated with enhanced preferences at the individual item level, both immediately and 1 mo following CAT. Our findings suggest that memory plays a central role in value-based decision-making following CAT, even in the absence of external reinforcements. These findings contribute to new theories relating memory and value-based decision-making and set the groundwork for the implementation of novel nonreinforced behavioral interventions that lead to long-lasting behavioral change.

Value-based decision-making and memory are both extensively studied processes in cognitive psychology and cognitive neuroscience (Fellows 2017). Most theories of value-based decision-making have focused on processes related to the incremental learning of value following external reinforcement, but have not explicitly addressed the role of memory per se. Thus, fundamental questions remain regarding interactions between memory and value-based decisions, which have been gaining attention in recent years.Several recent empirical studies have demonstrated interactions between episodic memory and value-based decision-making. For example, memory for past events has been shown to bias value-based decisions (Duncan and Shohamy 2016), differently for choices of novel versus choices of familiar options (Duncan et al. 2019), and choice behavior and fMRI signals during value-based decision-making were better explained by episodic memory for individual past choices than by a standard reinforcement learning model (Bornstein et al. 2017). Another study has found that during sampling of episodic memories of previous choices, the retrieved context influenced present choices, deviating from the predictions of standard reinforcement learning models (Bornstein and Norman 2017). Other studies have demonstrated that the long time known effect of choices on future preferences is related to memory processes (Chammat et al. 2017; DuBrow et al. 2019; Luettgau et al. 2020). At the neural level, the ventromedial prefrontal cortex (vmPFC) and the hippocampus both have been shown to play a role in memory processes and value-based decisions (Weilbächer and Gluth 2017) and recent studies have been further emphasizing that the hippocampus bridges between past experience and future decisions (Bakkour et al. 2019; Biderman et al. 2020).All these studies, and many others, highlighted the interaction between memory and value-based decision-making involving external reinforcements. However, everyday life involves decisions and associations that are not directly reinforced. Thus, it remains unclear whether memory plays a general role in value-based decision-making even without external reinforcements.To better understand the role of memory processes in shaping preferences independently of external reinforcements, we used a novel behavioral change paradigm, named cue-approach training (CAT). In this paradigm, associating images of items with a neutral cue and a speeded motor response results in a consistent preference enhancement without external reinforcement, which is maintained for months (Schonberg et al. 2014; Bakkour et al. 2018; Salomon et al. 2018, 2019; Botvinik-Nezer et al. 2020). During CAT, images of items are consistently paired with a neutral cue and a speeded motor response (“Go items”), while other items are presented without the cue or the response (“NoGo items”). One training session with several presentations of all items leads to long-lasting preference changes, measured as the likelihood of choosing Go over NoGo items that had similar initial subjective values (Schonberg et al. 2014). Results from over 30 samples with this paradigm have demonstrated a replicable effect on various types of stimuli, including snack food items, fruits and vegetables, unfamiliar faces, fractal art images, and positive affective images (Bakkour et al. 2016, 2017; Veling et al. 2017; Zoltak et al. 2017; Bakkour et al. 2018; Salomon et al. 2018, 2019; Botvinik-Nezer et al. 2020), revealing the potential of the CAT paradigm as an experimental platform for value-based decision-making without external reinforcements (Schonberg and Katz 2020).The underlying mechanisms of the change of preferences following CAT are not yet fully understood (Schonberg et al. 2014; Bakkour et al. 2017; Salomon et al. 2019; Botvinik-Nezer et al. 2020; Schonberg and Katz 2020). The long-lasting nature of the effect, which has been shown to last for up to 6 mo following a single training session (Schonberg et al. 2014; Salomon et al. 2018, 2019; Botvinik-Nezer et al. 2020), raises the hypothesis that memory processes are involved in its maintenance. Furthermore, previous studies have found enhanced memory for Go compared with NoGo items with other types of Go–NoGo tasks (Chiu and Egner 2015a,b; Yebra et al. 2019) and for items for which participants have a sense of agency (Murty et al. 2015). One recent study provided preliminary evidence suggesting that memory is involved in preference change following a similar nonreinforced Go/NoGo training task (Chen et al. 2021).We hypothesized that CAT enhances memory of Go items, which in turn leads to preferring these items over NoGo items. Previous neuroimaging findings with CAT that suggested possible interactions between hippocampal fMRI activity and subsequent preferences 1 mo following CAT, provide additional evidence in support of this hypothesis (Botvinik-Nezer et al. 2020). Therefore, here we set out to test the role memory processes play in the behavioral change of preferences following CAT, in the short and in the long term.We propose an underlying mechanism for the CAT effect, in which preference change following CAT results from a boost in memory encoding of positive Go items, which in itself is a consequence of enhanced perceptual processing of Go items (Schonberg et al. 2014; Botvinik-Nezer et al. 2020). We hypothesize that the enhanced encoding of Go items, as well as the greater perceptual activation in response to them, increases accessibility of attributes and associations of these specific Go items (Anderson 1983; Bhatia 2013). Furthermore, we hypothesized that preference changes, reflected in the binary choice phase, are due to the enhanced accessibility of memory associations of the Go items, which tips the scales in favor of the Go items when the associations are positive.In order to test memory for individual items, in the current work we introduced a memory recognition task following CAT. In two independent preregistered experiments and one pilot experiment, memory was evaluated following a long (16 repetitions) or short (a single exposure) CAT training session, before the probe phase that evaluated post-training preferences. We then tested our predictions that (1) memory will be stronger for Go compared with NoGo items following CAT (more accurate and faster responses in the recognition task) and (2) that memory will be related to choices (better remembered Go items will be chosen over worse remembered NoGo items). Since the link between better memory and enhanced choices is hypothesized to be related to positive associated memories, we tested the relationship between memory and choices separately for choices between low-value and choices between high-value items. These hypotheses were tested both in the short term (immediately or a few days after CAT) and in a 1-mo follow-up.     

Memory for unidentified items: Evidence for the use of letter information in familiarity processes

Participants can give accurate recognition judgments to word fragments that they are unable to complete. In three experiments, the generality of this finding was examined across tasks. Accurate memory judgments in the absence of identification were obtained in item recognition and judgments of presentation frequency but not in associative recognition or list discrimination. The former two tasks are thought to involve the use of familiarity; the latter two are thought to rely on recollection. The present results are consistent with the claim that recognition without identification reflects familiarity processes.     

Memory and conceptual learning of relevant and non-relevant items in item-method directed forgetting

The present research investigates the fate of non-target information when people are trying to either intentionally memorise or forget target information. By using an object-based attentional manipulation within a directed forgetting paradigm (item-method), we show a directed forgetting effect (DFE, i.e., better memory for to-be-remembered (TBR) than for to-be-forgotten (TBF) items) for items that participants are explicitly instructed to attend but not for irrelevant items that happen to be part of the context. Alongside the classic DFE, we investigate how the category of the attended and unattended items are learned. The results obtained in three experiments, show that people can successfully learn only the category of the TBR attended items and that the DFE extends to new items that are related to the old TBR and TBF items (an effect that we call conceptual DFE). These results give us new insight about how TBR and TBF items are processed and conceptually learned.     

Memory conformity for confidently recognized items: The power of social influence on memory reports

Memory conformity occurs when one person's memory report influences another's. Memory conformity is more likely to occur when the information comes from a credible source, and when internal evidence is weak. Here, we investigate whether there are situational variations in how heavily participants weigh internal cues to accuracy when confronted with conflicting information from a partner. The results show that even confidently held memories are subject to influence from external sources, and that social influence is exaggerated when the source is seen to be highly credible.     

Some properties of the correlation matrix of dichotomous guttman items

Both the elements and the eigenvalues of the Pearson correlation matrix of dichotomous Guttman-scalable items can be expressed as simple functions of the number of items if the score distribution is uniform and there is an equal number of items at each difficulty level. Even when these special conditions do not hold, the correlations can often be expressed in a simple form by assuming a particular score distribution.The author thanks Neil Dorans, Bob Mislevy, Ledyard R Tucker, and Howard Wainer for their comments.     

Preference for leisure items over edible items in individuals with dementia: A replication

We replicated previous research in which adults with dementia tended to show a preference for leisure items over edible items when presented in the same array. Additionally, we conducted engagement analyses with the highest, middle, and lowest preference leisure items to determine whether relative preference corresponded to engagement in the natural environment. The most highly preferred stimulus for 6 out of 7 participants was a leisure item, and for each of those six the top 3 preferred stimuli were leisure stimuli. For 4 participants, the most preferred stimulus also produced the longest duration of engagement. We discuss the issues we encountered when conducting preference assessments with adults with intact vocal verbal repertoires, and suggest potential explanations for the displacement of edibles by leisure stimuli in older adults with dementia.     

Recognition memory for prose items in noise

Using a probe-recognition technique the signal detection theory parameters d' and Beta were estimated for three types of probe (common surnames, uncommon surnames and synonyms) for material contained in a prose passage. Subjects were presented with the prose passage either in the presence of noise (85dBA) or in quiet (60dBA). In two experiments the effects of noise on auditory and visual presentation of the passage were studied. In both cases the recognition test took place in quiet. Noise decreased values of Beta for rare names and increased Beta for common names in both auditory and visual versions of the task. Noise influenced d' values in the auditory version only, with d' increasing for common names in loud noise. The results support the view that noise influences performance by disturbing the pigeon-holing mechanism with the qualification that when material may not be recapitulated (as in the auditory presentation in the present study) greater attention may be allocated to easily recognizable material. The findings give little support to theories of noiseinduced deficits in performance based on the masking of inner speech.     

Search processes for detecting repeated items In a visual display

Evidence for successive serial exhaustive searches was found in a task requiring detection of repeated letters in visually presented lists of varying length. The time per comparison was 25 msec. Important differences in processing appeared between instances of adjacent repeated letters and instances of nonadjacent repeated letters.     

Free‐listed items are effective cues for eliciting additional items in semantic domains

This study tested a cueing procedure for enhancing recall in semantic domains based on associative processes inferred from semantic clustering. Participants first free listed items exhaustively from a semantic domain (fruits or drugs). Then, to aid recall of additional items from the domain, participants received either the items they free listed as semantic cues (to trigger semantically similar items) or alphabetic cues (to trigger items beginning with a particular letter). Participants' strong semantic clustering and weak alphabetic clustering in free listing confirmed previous research on associative processes. By several measures, free‐listed items as semantic cues elicited moderately more additional items than alphabetic cues. Semantic cues elicited an appreciable proportion of items that would not have been identified at the aggregate level through free listing alone. These results indicate that using free‐listed items as semantic cues can be a useful adjunct for ethnographic applications of free listing. Copyright © 2002 John Wiley & Sons, Ltd.     

Memory for intention-related material presented in a to-be-ignored channel

Three experiments were conducted to investigate the fate of intention-related material processed in a to-be-ignored channel. Participants were given an intention to respond to cues in a visual-processing stream while simultaneously trying to ignore information being presented in an auditory stream. Subsequent to the ongoing activity, a surprise recognition test for information presented in the to-be-ignored auditory modality was administered. As compared with comparable neutral information, corrected recognition memory for intention-related material was significantly better, depending on the type of event-based prospective memory task. These results suggest that holding certain kinds of intentions can bias attentional processes in a manner consistent with a perceptual readiness for uptake of intention-related material.     

Memory for the pitch of a tone

Observers attempted to detect the presence of a pitch dirference between two successive tones. The percentage of correct judgments was equivalent for tones separated by 95, 4.5, and 8.9 sec. There was a general increase in reports of a pitch difference with increased intertone interval, which is interpreted as arising from hypothesized shifts in the neural locus of the first stimulus during the intertone interval.     

Memory for the pitch of a tone

Observers attempted to detect the presence of a pitch difference between two successive tones. The percentage of correct judgments was equivalent for tones separated by .95, 4.5, and 8.9 sec. There was a general increase in reports of a pitch difference with increased intertone interval, which is interpreted as arising from hypothesized shifts in the neural locus of the first stimulus during the intertone interval.     

Static items are automatically prioritized in a dynamic environment

Everyday experience provides us with the intuition that dynamic events guide or capture attention—something which has been confirmed in experimental studies. Recently, we showed that there are limitations to the extent to which dynamic items attract attention. In a visual search task where all items, except one, were dynamic, the dynamic items could be ignored and the static item could be efficiently detected. In the present study we investigated whether attention is automatically drawn to the static item. Three visual search experiments, in which the target and the static object were uncorrelated, revealed that the static item was nevertheless prioritized. This result is at odds with some of the current theories on attentional capture, including the “new object” hypothesis. The current study suggests that differences in dynamics, rather than dynamic features per se, determine where attention is allocated.     

Memory in a Whiteheadian Perspective

Whitehead does not provide us with a systematic account of the various types of experience to which the word “memory” is applied. Nevertheless, he does provide us with a way of understanding the world, and living creatures who inhabit it, that places the discussion in a different context from the usual one: the diverse features of human experience that we call memory are developed forms of basic patterns of relationship that characterize all actual entities. I will first review the relevant features of Whitehead's conceptuality, then contrast the resulting view with its usual formulation, and then speculate about some forms of memory in Whiteheadian categories.     

Tasks for Assessing Memory for Temporal Order Versus Memory for Items in Aging

Younger and older adults were compared on new tests for item and temporal memory suitable for use in future electrophysiological or neuroimaging studies. Following a series of 10 simple line drawings, 4-choice panels containing two previously seen targets and two novel distractors appeared. Participants identified which pictures had been seen previously (item), or which of the items was presented earliest (temporal order). Performance of younger adults was superior to that of older adults. Memory for item and temporal order were equivalent in the younger group. In contrast, the item memory of the older group was superior to memory for temporal order, confirming previous evidence of differential impairment of memory for temporal order with age.