Conscious and unconscious influences of memory for object location

The process-dissociation procedure was used to investigate conscious and unconscious influences of memory for object location. In two experiments, subjects worked with drawings of household objects and rooms of a house depicted on a computer monitor to simulate placing objects in various locations. Memory for object locations was tested by having subjects search for those objects. A double dissociation was obtained between estimates of conscious and unconscious influences of memory computed from equations that assumed independence between these two influences: Age-related differences were found in the estimate of conscious influences, but not in the estimate of unconscious influences, whereas manipulation of habit strength affected the unconscious estimate, but not the conscious estimate. These results were closely fit by a multinomial model assuming independence between conscious and unconscious influences of memory.     

Process dissociation procedure reveals age differences in unconscious influences on memory for possible and impossible objects

Abstract

Forty-eight younger and 48 older adults performed inclusion and exclusion tasks for line drawings of possible and impossible objects that were encoded semantically or globally. Participants' performance was transformed into estimates of conscious and unconscious influences on memory via the Process Dissociation Procedure (PDP). Five major findings were obtained. First, developmental differences were observed in the relative strength of conscious and unconscious influences on memory such that conscious influences were stronger for younger than older adults, whereas unconscious influences were stronger for older than younger adults. Second, unconscious influences on memory were demonstrated for possible and impossible objects. Third, unconscious influences on memory were obtained for objects that were encoded in both a global and a semantic fashion. Fourth, age-related differences in conscious and unconscious influences on memory were unaffected by object type. Fifth, estimates of conscious and unconscious influences on memory were unrelated to scores on psychometric measures of visual-spatial ability: Primary Mental Ability-Space (PMA-Space) and Benton Facial Recognition Task (BFRT). Collectively, these findings have implications for our understanding of the relative strength of conscious and unconscious memory processes in younger and older adults as well as the different types of unconscious memory processes that are recruited by the PDP in comparison to the traditional priming methodology.     

Adult Age Differences in Conscious and Unconscious Influences on Memory for Novel Associations

Forty-eight younger and 48 older adults generated sentences under self-paced conditions for semantically unrelated word pairs. Then they completed word + word stem pairs under inclusion and exclusion instructions for items that appeared in the same or different context relative to study. Performance on the inclusion and exclusion tasks was transformed into estimates of conscious and unconscious influences on memory by a series of equations as specified by Jacoby's (1991) Process Dissociation Procedure (PDP). Three notable findings were obtained. First, younger and older adults displayed a context effect when conscious, but not unconscious, influences on memory were considered. Second, age invariance in the strength of unconscious influences on memory was observed when data analysis was performed on the entire subject sample. In contrast, the estimated strength of unconscious contributions to memory was stronger for younger than older adults when data analysis was restricted to participants who made errors on the exclusion task. Third, conscious influences on memory were stronger for younger than older adults regardless of which method of data analysis was used. Taken together, these findings shed light on previous research which has examined the complex relationship between age, test awareness, and the implicit retention of novel verbal associations. They also highlight some of the methodological issues regarding the use of the PDP to measure age-related differences in the strength of unconscious memory processes.     

The impact of different directed forgetting instructions on implicit and explicit memory: New evidence from a modified process dissociation procedure

In contrast to previous research on directed forgetting, the present studies adopted a recent modification of the process dissociation procedure (Jacoby, 1991; Richardson-Klavehn & Gardiner, 1995) to accommodate the cross-contamination of memory test performance by implicit and explicit memorial factors. In Experiment 1, 120 subjects were compared in global directed forgetting, item-by-item directed forgetting, and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. In Experiment 2, 80 subjects were compared in specific directed forgetting and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. Subjects showed significant decrements in voluntary and involuntary conscious memory performance following instructions for directed forgetting in all conditions. None of the directed forgetting conditions showed a decrement in involuntary unconscious memory performance. Results suggest that, regardless of instruction type, directed forgetting prevents the conscious expression of memorial information (both voluntary and involuntary) while leaving unconscious memory intact.     

Conscious and unconscious processes: the effects of motivation

The process-dissociation procedure has been used in a variety of experimental contexts to assess the contributions of conscious and unconscious processes to task performance. To evaluate whether motivation affects estimates of conscious and unconscious processes, participants were given incentives to follow inclusion and exclusion instructions in a perception task and a memory task. Relative to a control condition in which no performance incentives were given, the results for the perception task indicated that incentives increased the participants' ability to exclude previously presented information, which in turn both increased the estimate of conscious processes and decreased the estimate of unconscious processes. However, the results also indicated that incentives did not influence estimates of conscious or unconscious processes in the memory task. The findings suggest that the process-dissociation procedure is relatively immune to influences of motivation when used with a memory task, but that caution should be exercised when the process-dissociation is used with a perception task.     

Does opposition logic provide evidence for conscious and unconscious processes in artificial grammar learning?

The question of whether studies of human learning provide evidence for distinct conscious and unconscious influences remains as controversial today as ever. Much of this controversy arises from the use of the logic of dissociation. The controversy has prompted the use of an alternative approach that places conscious and unconscious influences on memory retrieval in opposition. Here we ask whether evidence acquired via the logic of opposition requires a dual-process account or whether it can be accommodated within a single similarity-based account. We report simulations using a simple neural network model of two artificial grammar learning experiments reported by that dissociated conscious and unconscious influences on classification. The simulations demonstrate that opposition logic is insufficient to distinguish between single- and multiple-system models.     

内隐记忆的证明逻辑与加工分离说（PDP）的修正模型

讨论了内隐记忆的证明逻辑和内隐与外显测验中的意识和无意识影响问题。间接证明内隐记忆的逻辑应用在功能分离实验中。它的前提假设是记忆测验都是＂纯净＂的。直接证明逻辑应用在匹配比较实验中。它认为测验中的意识和无意识影响是并存的,Ｊａｃｏｂｙ等人近期提出的加工分离说（ＰＤＰ）在匹配比较法的基础上,将测验中的意识和无意识影响进行了分离,并借用经典测验理论的公式计算这两种影响。作者认为,按照概率论关于两个随机独立事件之和与积的运算法则,必须把包含测验（ｉｎｃｌｕｓｉｏｎｔｅｓｔ）的公式修正为Ｉｎｃｌｕｓｉｏｎ＝Ｒ（１－ａ）＋Ａ（１－Ｒ）。修正过的ＰＤＰ由四个方程组成。它不仅考虑了原ＰＤＰ忽视的外显条件下的无意识缺失（１－ａ）,而且可以更加确切地估计回忆概率（Ｒ）。这在数学理论上已找到了证据。     

Unconscious influences on direct-test performance

From intense interest in implicit memory there have evolved various methods for separating the respective influence of implicit (unconscious) and explicit (conscious) processes on performance of various tasks. Two experiments are reported, utilizing a levels-of-processing (LOP) approach to manipulate encoding level and comparable indirect (word-stem completion) and direct (cued-completion) retention tests. Confidence ratings of recollection were taken for each direct test response. The aim of these experiments was to explore the role that guessing plays in direct-test performance (Experiments 1 and 2) and to contrast this with performance in a comparable indirect test (Experiment 2). Analysis of correctly guessed responses showed that direct-test performance was reliably influenced by unconscious processes, but differently as a function of LOP. Guessing stems of nonsemantically processed words was found to enhance performance, whereas guessing stems of semantically processed words had no effect on performance. Results are discussed in terms of the similarity between guessing in a direct test and engaging in an indirect test, and subjects' unwitting resourcefulness at being able to retrieve words they cannot explicitly remember.     

Think different: the merits of unconscious thought in preference development and decision making

The role of unconscious and conscious thought in decision making was investigated in 5 experiments. Because of the low processing capacity of consciousness, conscious thought was hypothesized to be maladaptive when making complex decisions. Conversely, unconscious thought was expected to be highly effective. In Experiments 1-3, participants were presented with a complex decision problem in which they had to choose between various alternatives, each with multiple attributes. Some participants had to make a decision immediately after being presented with the options. In the conscious thought condition, participants could think about the decision for a few minutes. In the unconscious thought condition, participants were distracted for a few minutes and then indicated their decision. Throughout the experiments, unconscious thinkers made the best decisions. Additional evidence obtained in Experiments 4 and 5 suggests that unconscious thought leads to clearer, more polarized, and more integrated representations in memory.     

The role of conscious memory in the category-production task

This study reported two experiments using the category-production task to examine the role of conscious memory in the conceptual indirect test of memory. Experiment 1 tested participants on both the category-production and recall tasks and found that, when participants were given ample time to do the production task, their production performance could be fully accounted for by their recall performance. On the other hand, priming was still found in the early production when intentional retrieval was unlikely to occur, indicating the influence of involuntary memory. Experiment 2 replicated the main finding of Experiment 1. More importantly, evidence from the exclusion instruction condition showed that there was no involuntary unconscious memory. These two experiments also demonstrated a dissociation of the delay effect between the category-production and recall tests, as well as a parallel levels-of-processing effect on these two tests. Results are discussed in terms of the nature of priming in the conceptual indirect test.     

Unconscious priming of task sets: The role of spatial attention

Unconscious stimuli activate task sets, mental programs that orchestrate performance of complex tasks, but the role of attention in such effects has not been addressed. In previous studies, unconscious prime stimuli appeared at attended locations and were explicitly specified in the task instructions; spatial attention to the prime and/or a specific conscious attentional set may thus be required for such unconscious activation to arise. In the present experiments, a learning phase established associations between unconscious prime stimuli and performance of two tasks. These associations influenced task performance in a subsequent test phase, even though the primes were not specified in current task instructions. This is the first demonstration that unconscious stimuli can prime task sets independently of a current attentional set that specifies stimulus-task mappings. Such priming was not influenced by spatial attention cues, in contrast to clear attention influences in comparison trials that mimicked conditions employed by previous studies.     

Implicit learning shapes new conscious percepts and representations

We present here the lineaments of a new account of implicit learning, an account that does not rely on the notion of “implicit knowledge.” In this account, improved performance depends on the action of unconscious mechanisms that structure the phenomenal, conscious experience of the world. This integrative view makes groundless the search for dissociations between conscious and unconscious influences that has been at the core of the research on implicit learning and memory. We contrast this view, on the one hand, to Dienes and Berry’s (1997) proposal, which defines implicit learning by analogy with subliminal perception, and, on the other, to Neal and Hesketh’s (1997) episodic account, in which subjective experience is a starting point for inquiry, rather than the phenomenon requiring explanation.     

Unconscious influences revealed. Attention, awareness, and control.

Recent findings of dissociations between direct and indirect tests of memory and perception have renewed enthusiasm for the study of unconscious processing. The authors argue that such findings are heir to the same problems of interpretation as are earlier evidence of unconscious influences--namely, one cannot eliminate the possibility that conscious processes contaminated the measure of unconscious processes. To solve this problem, the authors define unconscious influences in terms of lack of conscious control and then describe a process dissociation procedure that yields separate quantitative estimates of the concurrent contributions of unconscious and consciously controlled processing to task performance. This technique allows one to go beyond demonstrating the existence of unconscious processes to examine factors that determine their magnitude.     

Conscious and unconscious influences on remembering information from the near and distant past: A developmental analysis

We examined adults' memory for the actors and actresses who won Academy Awards for their performances in specific motion pictures between 1992 to 1937. Fifty-six individuals between 41 to 81 years of age completed inclusion and exclusion versions of aMovie Memory Questionnaire in which they were required to identify actors and actresses who were paired with the names of movies they actually appeared in (e.g., Cher—Moonstruck) or they never appeared in (e.g., Robert DeNiro—Annie Hall), respectively. Estimates of the independent contributions of conscious and unconscious influences on recollection were obtained by analyzing subjects' performance on the inclusion and exclusion tasks via Jacoby's (1991)Process Dissociation Procedure. Results indicated that conscious recollection for motion picture information exhibited a typical retention function, whereas unconscious contributions to recollection remained relatively constant over the entire time range that was sampled. When age differences were considered, it was found that young-old participants displayed a higher level of conscious recollection than did middle-age and old-old adults. The role played by unconscious processes in recollection, however, did not vary by age group.     

Effects of divided attention on perceptual and conceptual memory tests: An analysis using a process-dissociation approach

In two experiments, the nature of the relation between attention available at learning and subsequent automatic and controlled influences of memory was explored. Participants studied word lists in full and divided encoding conditions. Memory for the word lists was then tested with a perceptually driven task (stem completion) in Experiment 1 and with a conceptually driven task (category association) in Experiment 2. For recall cued with word stems, automatic influences of memory derived using the process-dissociation procedure remained invariant across a manipulation of attention that substantially reduced conscious recollection for the learning episode. In contrast, for recall cued with category names, dividing attention at learning significantly reduced the parameter estimates representing both controlled and automatic memory processes. These findings were similar to those obtained using indirect test instructions. The results suggest that, in contrast to perceptual priming, conceptual priming may be enhanced by semantic processing, and this effect is not an artifact of contamination from conscious retrieval processes.     

Turning the process-dissociation procedure inside-out: A new technique for understanding the relation between conscious and unconscious influences

While there is now general agreement that memory gives rise to both conscious and unconscious influences, there remains disagreement concerning the process architecture underlying these distinct influences. Do they arise from independent underlying systems (e.g., Jacoby, 1991) or from systems that are interactive (e.g., Joordens & Merikle, 1993)? In the current paper we present a novel “inside-out” technique that can be used with the process-dissociation paradigm to arrive at more concrete conclusions concerning this central question and demonstrate this technique via a meta-analysis of currently published findings. Our results suggest that the data presented in these studies vary in ways most consistent with the assumption that conscious and unconscious influences behave independently.     

Recognition memory for words and pictures at short and long retention intervals

In two experiments, subjects studied a long series of words and pictures for recognition. Retention intervals varied from several minutes to a few months. The complicated testing procedures in Experiment I required the use of a traditional correction for guessing to obtain estimates of subjects' memory performance. A comparable, but simpler, design in Experiment II permitted the calculation of sensitivity and bias measures. In both studies, pictorial memory was superior to verbal memory at all retention intervals tested, and this advantage was essentially constant over time. In addition, the experiments identified an increasing tendency to call verbal test items "old" over time. Bias scores in Experiment H revealed that subjects adopted a more lenient criterion in responding to words than to pictures, and increased leniency was noted for both item types over time. Explanations of the results are offered in terms of differences in initial encoding and of a loss of discrimination between experimental and extraexperimental materials.     

Where creativity resides: the generative power of unconscious thought

In three experiments, the relation between different modes of thought and the generation of "creative" and original ideas was investigated. Participants were asked to generate items according to a specific instruction (e.g., generate place names starting with an "A"). They either did so immediately after receiving the instruction, or after a few minutes of conscious thought, or after a few minutes of distraction during which "unconscious thought" was hypothesized to take place. Throughout the experiments, the items participants listed under "unconscious thought" conditions were more original. It was concluded that whereas conscious thought may be focused and convergent, unconscious thought may be more associative and divergent.     

Cognitive style modulates conscious but not unconscious thought: Comparing the deliberation-without-attention effect in analytics and wholists

Unconscious thought theory (UTT) suggests that conscious thinking is less effective in complex decision-making than unconscious thinking. However, little research has taken individual differences (e.g., cognitive style) into account. Using an adapted UTT paradigm, the present study compared the performances of individuals with a wholist or an analytic cognitive style in both conscious and unconscious thought conditions. After viewing information regarding four hypothetical phones, participants in the conscious thought condition deliberated for three minutes before rating the phones, while participants in the unconscious thought condition were distracted with a 2-back task for three minutes before rating. The results showed that wholists were equally good at differentiating good and bad phones after conscious or unconscious thought, whereas analytics performed well only when thinking unconsciously. The modulation effect of cognitive style appeared only in conscious thought. Implications for UTT and the understanding of cognitive style are discussed.